Axillary Lymph Node Metastasis Research Articles

Axillary lymph node metastasis in pure mucinous carcinoma of breast: clinicopathologic and ultrasonographic features

BackgroundThe purpose of this research is to study the sonographic and clinicopathologic characteristics that associate with axillary lymph node metastasis (ALNM) for pure mucinous carcinoma of breast (PMBC).MethodsA total of 176 patients diagnosed as PMBC after surgery were included. According to the status of axillary lymph nodes, all patients were classified into ALNM group (n = 15) and non-ALNM group (n = 161). The clinical factors (patient age, tumor size, location), molecular biomarkers (ER, PR, HER2 and Ki-67) and sonographic features (shape, orientation, margin, echo pattern, posterior acoustic pattern and vascularity) between two groups were analyzed to unclose the clinicopathologic and ultrasonographic characteristics in PMBC with ALNM.ResultsThe incidence of axillary lymph node metastasis was 8.5% in this study. Tumors located in the outer side of the breast (upper outer quadrant and lower outer quadrant) were more likely to have lymphatic metastasis, and the difference between the two group was significantly (86.7% vs. 60.3%, P = 0.043). ALNM not associated with age (P = 0.437). Although tumor size not associated with ALNM(P = 0.418), the tumor size in ALNM group (32.3 ± 32.7 mm) was bigger than non-ALNM group (25.2 ± 12.8 mm). All the tumors expressed progesterone receptor (PR) positively, and 90% of all expressed estrogen receptor (ER) positively, human epidermal growth factor receptor 2 (HER2) were positive in two cases of non-ALNM group. Ki-67 high expression was observed in 36 tumors in our study (20.5%), and it was higher in ALNM group than non-ALNM group (33.3% vs. 19.3%), but the difference wasn’t significantly (P = 0.338).ConclusionsTumor location is a significant factor for ALNM in PMBC. Outer side location is more easily for ALNM. With the bigger size and/or Ki-67 higher expression status, the lymphatic metastasis seems more likely to present.

A nomogram based on conventional and contrast-enhanced ultrasound radiomics for the noninvasively prediction of axillary lymph node metastasis in breast cancer patients

BackgroundThis study aimed to investigate whether quantitative radiomics features extracted from conventional ultrasound (CUS) and contrast-enhanced ultrasound (CEUS) of primary breast lesions can help noninvasively predict axillary lymph nodes metastasis (ALNM) in breast cancer patients.MethodA total of 111 breast cancer patients with 111 breast lesions were prospectively enrolled. All the included patients received presurgical CUS screening and CEUS examination and were randomly assigned to the training and validation sets at a ratio of 7:3 (n = 78 versus 33). Radiomics features were respectively extracted based on CUS and CEUS using the PyRadiomics package. The max-relevance and min-redundancy (MRMR) and least absolute shrinkage and selection operator (LASSO) analyses were used for feature selection and radiomics score calculation in the training set. The variance inflation factor (VIF) was performed to check the multicollinearity among selected predictors. The best performing model was selected to develop a nomogram using binary logistic regression analysis. The calibration and clinical utility of the nomogram were assessed.ResultsThe model combining CUS reported ALN status, CUS radiomics score (CUS-radscore) and CEUS radiomics score (CEUS-radscore) exhibited the best performance. The areas under the curves (AUC) of our proposed nomogram in the training and external validation sets were 0.845 [95% confidence interval (CI), 0.739-0.950] and 0.901 (95% CI, 0.758-1). The calibration curves and decision curve analysis (DCA) demonstrated the nomogram’s robust consistency and clinical utility.ConclusionsThe established nomogram is a promising prediction tool for noninvasive prediction of ALN status. The radiomics features based on CUS and CEUS can help improve the predictive performance.

Longitudinal ultrasound-based AI model predicts axillary lymph node response to neoadjuvant chemotherapy in breast cancer: a multicenter study.

Developing a deep learning radiomics model from longitudinal breast ultrasound and sonographer's axillary ultrasound diagnosis for predicting axillary lymph node (ALN) response to neoadjuvant chemotherapy (NAC) in breast cancer. Breast cancer patients undergoing NAC followed by surgery were recruited from three centers between November 2016 and December 2022. We collected ultrasound images for extracting tumor-derived radiomics and deep learning features, selecting quantitative features through various methods. Two machine learning models based on random forest were developed using pre-NAC and post-NAC features. A support vector machine integrated these data into a fusion model, evaluated via the area under the curve (AUC), decision curve analysis, and calibration curves. We compared the fusion model's performance against sonographer's diagnosis from pre-NAC and post-NAC axillary ultrasonography, referencing histological outcomes from sentinel lymph node biopsy or axillary lymph node dissection. In the validation cohort, the fusion model outperformed both pre-NAC (AUC: 0.899 vs. 0.786, p < 0.001) and post-NAC models (AUC: 0.899 vs. 0.853, p = 0.014), as well as the sonographer's diagnosis of ALN status on pre-NAC and post-NAC axillary ultrasonography (AUC: 0.899 vs. 0.719, p < 0.001). Decision curve analysis revealed patient benefits from the fusion model across threshold probabilities from 0.02 to 0.98. The model also enhanced sonographer's diagnostic ability, increasing accuracy from 71.9% to 79.2%. The deep learning radiomics model accurately predicted the ALN response to NAC in breast cancer. Furthermore, the model will assist sonographers to improve their diagnostic ability on ALN status before surgery. Our AI model based on pre- and post-neoadjuvant chemotherapy ultrasound can accurately predict axillary lymph node metastasis and assist sonographer's axillary diagnosis. Axillary lymph node metastasis status affects the choice of surgical treatment, and currently relies on subjective ultrasound. Our AI model outperformed sonographer's visual diagnosis on axillary ultrasound. Our deep learning radiomics model can improve sonographers' diagnosis and might assist in surgical decision-making.

Abstract PS01-04: To dissect or not to dissect? The surgeon’s perspective on the prediction of ≥ 4 axillary lymph node metastasis in cN0 T1-2 breast cancer: A comparative analysis of the per-protocol population of the SINODAR-ONE clinical trial

Abstract Objectives The role of axillary surgery in the management of breast cancer (BC) has evolved considerably over the past decades, with only a few routine indications for axillary lymph node dissection (ALND) remaining in clinical practice. However, de-escalation of axillary surgery, especially in BC patients with 1-3 positive sentinel lymph nodes (SLNs) challenges the recently established criteria for adjuvant treatment (i.e., combination therapy with abemaciclib, endocrine therapy, and chemotherapy in patients with ≥ 4 positive nodes). The question remains as to whether these patients should undergo further ALND to determine whether ≥ 4 nodes are positive. To further investigate the latest controversies in axillary management of BC patients and predict the presence of ≥ 4 axillary lymph node metastasis, we evaluated and compared patients ≥ 4 positive nodes in the per-protocol population of the SINODAR-ONE clinical trial. Patients in the standard arm (ALND) of the per-protocol population were evaluated, and a comparison of characteristics between patients with ≥ 4 metastatic lymph nodes versus patients with 1-3 metastatic lymph nodes was performed. Categorical variables were compared using the chi-square test or Fisher’s exact test, as appropriate. Multivariable analysis was performed using a logistic regression model to identify independent predictors of ≥4 axillary lymph node metastasis. Results: Overall, 403 cN0 T1-2 BC patients in the per-protocol population were randomized to receive ALND. Of these, 65 and 338 patients presented with ≥ 4 or 1-3 axillary lymph node metastasis, respectively. Invasive lobular BC (26.2% versus 14.5% if other histology, odds ratio (OR)=4.185, 95% confidence interval (95%CI)= 1.284-1.443, p= 0.041), G3 (38.5% versus 21.3% if G1-2, OR=5.930, 95%CI= 2.134-2.289, p= 0.015), pT2 (46.2% versus 30.5% if pT1, OR=5.260, 95%CI= 15.330-16.346, p= 0.022), and 2 positive SLNs (32.3% versus 13.6% if 1 positive SLN, OR=13.188, 95%CI= 1.179-1.280, p&amp;lt; 0.0001) were found to significantly increase the probability to present ≥4 axillary lymph node metastasis at definitive histopathological evaluation. Conclusions: The introduction of abemaciclib and other combination therapies has the potential to impact the surgical management of the axilla. Our results suggest that a minority of cN0 T1-2 BC patients may be understaged if ALND is not performed. However, the improvements and increasing effectiveness of combination therapies may sufficiently control and treat the axillary tumor-burden left behind, potentially reducing the need for extensive axillary surgery, as demonstrated by the promising 3-year oncological outcomes of the SINODAR-ONE trial. Although ALND may still be considered, after multidisciplinary team discussion, in individual patients presenting with specific risk factors for additional axillary disease (lobular, G3, pT2 BC with 2 positive SLNs), our suggestion is that routine ALND is not indicated for systemic therapy decision-making in the upfront surgical setting. Citation Format: Damiano Gentile, Wolfgang Gatzemeier, Andrea Sagona, Erika Barbieri, Alberto Bottini, Alberto Testori, Valentina Errico, Simone Di Maria Grimaldi, Giulia Caraceni, Shadya Darwish, Giuseppe Canavese, Corrado Tinterri. To dissect or not to dissect? The surgeon’s perspective on the prediction of ≥ 4 axillary lymph node metastasis in cN0 T1-2 breast cancer: A comparative analysis of the per-protocol population of the SINODAR-ONE clinical trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS01-04.

Abstract PO4-07-10: Validation of An Ultrasound-Based Scoring System of Axillary Metastasis in Breast Cancer

Abstract Introduction: Ultrasound is the imaging modality of choice in the evaluation of axillary involvement in breast cancer. Our group previously created a scoring method to predict axillary lymph node metastasis (ALNM) based on ultrasound characteristics. In this study we validated the model and tested it among different Memorial Sloan Kettering Breast Cancer Sentinel Lymph Node Metastasis Nomogram1 (MSK) subgroups. Methods: The ultrasound score (table 1) was previously developed using data collected at a single institution from 2019 – 2021 by allocating points based on the regression coefficients of variables found to significantly predict ALNM. Subsequent evaluation of the discrimination of this model found it was robust to different patient demographic and tumor characteristics based on receiver operating characteristic curve analysis2. In this study, we validated the test statistics of our score at an outside institution. We also pooled patients from both institutions and evaluated the score performance in different MSK subgroups by the likelihood for sentinel node metastasis based off of clinical and pathologic data without accounting for imaging findings. Results: Between 2019-2021, 140 patients with breast cancer were analyzed for validation of the axillary ultrasound scoring system and when combined with the dataset of patients from the index institution, 358 pooled patients were stratified by predicted ALNM positivity according to MSK. In the validation cohort, the NPV for low risk (0-1) scores was 87%, while the PPV for high-risk (5+) scores was 71%. Overall in the combined cohort, 241 (67%) patients had low risk (0-1) axillary ultrasound scores and 33 (9%) had high risk (5+) scores. In this combined cohort, NPV was 84% (203/241 low-risk score patients were node negative), while PPV for high-risk scores was 85% (28/33 high risk score patients were node positive). When analyzed according to level of MSK predicted ALNM rates, for patients with &amp;lt; 50% predicted ALNM positivity, the NPV of low-risk scores was 87-89% and the PPV for high-risk axillary scores was 100%. For patients with &amp;gt;50% predicted ALNM positivity, the NPV of low-risk scores was 66% and the PPV of high-risk scores was 82%. Conclusions: A scoring system to predict ALNM among biopsy proven breast cancer patients undergoing upfront surgery was successfully developed from a multivariate model based on axillary ultrasound characteristics. This model was validated at a separate institution. The scoring system shows advantageous negative and positive predictive values for axillary node metastasis, especially among patients with &amp;lt; 50% predicted nodal involvement based on the MSK nomogram. This data may help foster better communication about ALNM risk between radiologists and treating clinicians to inform treatment decisions. Table. Scoring System for Likelihood of ALNM based on Ultrasound Characteristics Citation Format: Spencer Van Decar, Elizabeth Carpenter, Alexandra Adams, Jason Shore, Iulian Dragusin, Erika Davis, Craig Tork, Robert Krell, Troy Graybeal, Katherine Clifton, Arianna Buckley, Guy Clifton. Validation of An Ultrasound-Based Scoring System of Axillary Metastasis in Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-07-10.

Abstract PO3-23-03: Radar reflectors for marking of target lymph nodes in patients receiving neoadjuvant chemotherapy for breast cancer – a subgroup analysis of the prospective AXSANA (EUBREAST-03) trial

Abstract Background: Surgical staging procedures of the axilla in breast cancer patients converting from a clinically positive (cN+) to a clinically negative (ycN0) lymph node status during neoadjuvant chemotherapy (NACT) vary across countries and within individual countries. The international prospective AXSANA (EUBREAST-03) study aims at comparatively evaluating long-term outcomes of different staging procedures such as axillary lymph node dissection (ALND), sentinel lymph node biopsy (SLNB), target lymph node biopsy (TLNB) and targeted axillary dissection (TAD). The comparison of marking techniques for the target lymph node (TLN) is a secondary endpoint. In this subgroup analysis, we report on the largest yet prospective cohort of patients receiving a radar reflector for marking of the TLN prior to NACT. Methods: The AXSANA study is an international prospective cohort study including cN+ patients converting to ycN0 status and treated with different axillary staging techniques according to the standard at their treating institution. The study was initiated by the EUBREAST network and started enrollment in August 2020. Eligible patients have cT1-4c tumors, initially present with axillary lymph node metastasis and receive neoadjuvant chemotherapy. Patients converting to ycN0 status are followed up for 5 years irrespectively of the ypN status. In the present subgroup analysis, only patients with a TLN marked by a radar reflector were included. We prospectively examined the retrieval rate of radar reflectors and the identification rate of the TLN (defined as unequivocal removal of the lymph node, i.e., the presence of lymphatic tissue in the TLN specimen and/or pathological confirmation of post-NACT changes typical for metastatic lymph nodes responding to treatment). Results: A TLN was marked using a radar reflector in 74 patients prior to NACT. The median age was 52 years (range: 32-77). The most common subtype was no special type in 68 (92%) patients and invasive lobular cancer in 7 (7%) patients. Most patients (n = 44, 59%) had one suspicious node at time of diagnosis, followed by two (n = 15, 20%), three (n = 10, 14%) or ≥ four suspicious nodes (n = 5, 5%). Only one TLN was marked in 73 (99%) patients and two nodes were marked in one patient (1%). Fifteen patients (20%) had a MRI between marker placement and surgery. In 4 out of 15 cases (27%), MRI artifacts were described. However, the assessment of MRI was limited due to artifacts only in one out of these four patients (25%). Out of the 74 patients with radar reflector marked TLN, 45 (61%) had undergone final surgery at the time of analysis and 29 (39%) are still under NACT. 36 out of 45 patients (80%) who received final surgery converted to ycN0. Most patients had undergone a TAD (n = 41, 91%), followed by TLNB in 7% (n = 3) and upfront ALND in 2% of cases (n = 1). All radar reflectors were successfully removed. In 44 out of 45 patients (98%) the TLN was unequivocally identified and removed. In one patient the tissue specimen containing radar reflector consisted of fat tissue and no lymphatic tissue was identifiable, so it remains unclear whether the TLN was excised, or the reflector might have dislocated. 29 patients (65%) had converted to ypN0 status. Conclusion: To the best of our knowledge this is the largest prospective series of patients receiving a radar reflector for the marking of TLN prior to NACT for breast cancer. The removal rate of the marker and the detection rate of the target node were very high. Our data demonstrate that radar reflectors are a reliable tool for marking of target lymph nodes before neoadjuvant treatment. Citation Format: Maggie Banys-Paluchowski, Steffi Hartmann, Jana de Boniface, Oreste Davide Gentilini, Timo Basali, Elmar Stickeler, Michael Untch, Franziska Ruf, Sarah Fröhlich, Marc Thill, Michael P. Lux, Florentia Peintinger, Guldeniz Karadeniz Cakmak, Isabel Rubio, Michalis Kontos, Rosa Di Micco, Dawid Murawa, Ellen Schlichting, Bilge Aktas Sezen, Achim Rody, Dagmar Langanke, Nana Bündgen, Jose Ignacio Sanchez-Mendez, Renu Buss-Steidle, Christine Mau, Nana Buchmann, Sabine Riemer, Marit Helene Hansen, Nina Ditsch, Thorsten Kühn. Radar reflectors for marking of target lymph nodes in patients receiving neoadjuvant chemotherapy for breast cancer – a subgroup analysis of the prospective AXSANA (EUBREAST-03) trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-23-03.

Abstract PO4-22-12: Robot-assisted nipple-sparing mastectomy using da Vinci SP single-port system: primary results from the pilot trial RASPIM-01

Abstract Background Robot-assisted breast surgery was developed in 2014 for nipple-sparing mastectomy through a concealable lateral chest wall incision smaller. Although successful experiences have been reported using a multi-arm surgical robotic system, collisions between robotic arms and instruments often result in the discontinuation of console workflow and limit the performance of the surgical robot. Compared to multi-armed robot systems, the SP system is single-armed, equipped with flexible instruments containing multiple joints that may avoid instrument collision, a controllable camera reducing visual dead spots, and a designated non-third-party port that allows single-port entry and full deployment of the instrument. The RASPIM-01 trial (NCT05448963) is a single-armed pilot study assessing the feasibility of robot-assisted nipple-sparing mastectomy (NSM) using a new SP system. Method This study is a pilot trial conducted in a single-arm, non-randomized design with a recruitment of 30 participants. The SP surgical robot is used in NSM through the lateral chest wall incisions. The major inclusion criteria are 1) Breast cancer with preoperative clinical tumor sizes less than 5 cm, with an adequate tumor-skin distance of at least 3mm, and without nipple-areolar involvement in at least 1cm around the nipple by image, 2) Breast cancer up to clinical stage IIIA (T3, N1-2) showing adequate response to neoadjuvant therapy and meeting criteria 1), 3) Germline pathogenic/likely pathogenic BRCA1 or 2 variant carriers with or without a breast cancer diagnosis, requiring unilateral or bilateral therapeutic mastectomy or prophylactic mastectomy. Exclusion criteria include extensive breast skin or nipple involvement such as inflammatory breast cancer, Paget’s disease, nipple discharge associated with malignancy, image suggestive of cancer involvement of the nipple and subareolar tissue, and stage III breast cancer without response to neoadjuvant therapy, and previous radiotherapy of the surgical side breast. The endpoint measurements include Primary endpoint: The ability to complete nipple-sparing mastectomy with an SP system in the per-protocol population without additional assistant port or conversion to open surgery. Statistical analysis includes point estimation with a 95% confidence interval to analyze the mean or proportion of key performance parameters. No interim analysis will be performed due to the limited number intended to recruit. Results The study recruited 30 breast cancer patients and conducted 30 NSMs, while no prophylactic mastectomy case was recruited. The median age was 44 years old, BMI was 22.4 (18.9-30.0) kg/m2. Median tumor size was 3.0 (1.0-14.6) cm, and axillary lymph node metastases were present in 7 cases (23.3%). T2 (13 cases, 43.3%) tumors were the majority, followed by Tis (10 cases, 33.3%), T1 (5 cases, 16.7%), and T3 (2 cases, 6.7%). The anatomical stages of invasive cancer were Ia (16.7%), IIa (26.7%), IIb (16.7%), and IIIa (6.7%), among them 9 (30.3%) received neoadjuvant chemotherapy before surgery. All NSMs met the primary endpoint of successful completion using the SP robot system without conversion to open mastectomy or the addition of an assistant port. Median console time was 108.5 (73-285) min and docking time was 2.5 (1-9) min. Specimen weight was 311.6 (107-838) gm, while 2 (6.7%) cases had their nipple excised due to cancer-involved margin reported from the frozen section. Twenty-six (86.6%) cases received autologous free flap reconstruction, among which 25 (83.3%) cases received DIEP, and 1 (3.3%) received PAP reconstruction. Four cases received implant (2 cases, 6.7%) or tissue expander (3 cases, 6.7%). Conclusion This is the first NSM clinical trial operated with SP surgical robot system and met its primary endpoint showing the feasibility to conduct NSM. Secondary and exploratory endpoints data will be reported after the completion of clinical follow-ups. Citation Format: Wen-Ling Kuo, Chia-Huei Chu, Jung-ju Huang. Robot-assisted nipple-sparing mastectomy using da Vinci SP single-port system: primary results from the pilot trial RASPIM-01 [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-22-12.

Abstract PO5-27-12: TALL CELL CARCINOMA WITH REVERSED POLARITY: A RARE SUBTYPE OF INVASIVE BREAST CARCINOMA WITH UNUSUAL ONCOGENIC DRIVER MUTATION R132C IN IDH1 GENE

Abstract Introduction: Tall cell carcinoma with reversed polarity (TCCRP) is a rare subtype of invasive breast carcinoma with a distinguishing morphogical feature, which is the predilection of nuclei to polarize to the apical pole of tall columnar epithelial cells. These tumours are most commonly associated with IDH2 p.Arg172 hotspot mutations. All reported cases of TCCRP affected women ranging from 39 to 89 years (mean age of 64 years). The tumours presented as a mammographic or palpable mass, only rarely associated with axillary lymph node metastases. TCCRP are usually associated with an indolent clinical course and a favourable prognosis. Morphologically, TCCRP is composed of circumscribed nests of epithelial cells often exhibiting delicate fibrovascular cores, conveying a solid papillary pattern. True papillae and cystic structures containing colloid-like material may be observed in some cases. The tumour cells are tall and columnar, with abundant eosinophilic cytoplasm, containing bland, round to ovoid nuclei disposed at the apical pole of the columnar epithelial cells. Mitotic figures are rare. Most TCCRPs exhibit a triple-negative phenotype and a low (&amp;lt; 20%) Ki-67 proliferation index. Molecular features of TCCRP comprise IDH2 p.Arg172 hotspot mutations, reported in about 84% of the cases studied, as well as PIK3CA missense mutations, identified in about 68% of these tumours. Only one case of TCCRP was associated with IDH1 gene mutations according to the literature. Case report: A 62 year old woman presented with a palpable mass and no axillary adenopathy was identified. Hematoxylin-eosin (HE) stain showed an invasive breast carcinoma, with epithelial tumour cells arranged in a solid and papillary pattern with thin fibrovascular cores. Neoplastic cells are tall and columnar, with abundant eosinophilic cytoplasm and round to ovoid nuclei, exhibiting no pleomorphism and disposed in the apical pole of the cells. Mitotic figures were not detected. Considering the highly suggestive morphology on HE stain, biopsy sample was sent for molecular analysis by next generation sequencing (NGS). Results and discussion: Molecular analysis by NGS using the TruSight Oncology 500 panel (Illumina) revealed the presence of the oncogenic mutations R132C and H1047R in IDH1 and PIK3CA genes, respectively. Contrary to what occurs in almost all cases of Tall cell carcinoma with reversed polarity (TCCRP), in which an oncogenic mutation is described in codon R172 of the IDH2 gene, in this case a mutation was observed in the IDH1 gene. Such a mutation has been described in only one case diagnosed with TCCRP according to the literature, this being the second reported case. Conclusion: This case report aims to warn of the possibility that other driver mutations may be associated with the diagnosis of TCCRP, such as IDH1 R132 and not just IDH2 R172, and that a comprehensive testing approach of the IDH1/2 genes might be more accurate in these cases. Citation Format: Karla Prigenzi, Luiz Gustavo Ferreira Cortes, Paulo Vidal Campregher, João Bosco de Oliveira Filho, Nestor Andrade Piva. TALL CELL CARCINOMA WITH REVERSED POLARITY: A RARE SUBTYPE OF INVASIVE BREAST CARCINOMA WITH UNUSUAL ONCOGENIC DRIVER MUTATION R132C IN IDH1 GENE [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-27-12.

Abstract PO2-28-07: Artificial Intelligence-based Computer-aided Diagnosis for Mammography: Predicting Occult Invasive Cancer in Women with Biopsy-proven Ductal Carcinoma in Situ

Abstract Background: Ductal carcinoma in situ (DCIS) is a noninvasive breast cancer confined within the basement membrane. Due to the increase in breast cancer screening, DCIS is increasingly being diagnosed on biopsy. Active surveillance is a novel and evolving treatment strategy for DCIS to reduce overtreatment. Currently ongoing clinical trials of active surveillance include only mammographic findings in their eligibility criteria, however mammography has limited ability to detect occult invasive cancer. The objective of this study was to investigate whether an artificial intelligence-based computer-aided diagnosis (AI-CAD) application for mammography can improve the prediction of occult invasive cancer in women with percutaneous needle biopsy-proven DCIS. Methods: A retrospective search of our database identified consecutive women with percutaneous needle biopsy-proven DCIS who underwent surgery at Seoul National University Hospital (Seoul, Korea) between June 2019 and May 2021. Two board-certified breast radiologists reviewed preoperative mammographic findings of the primary tumor in consensus according to the Breast Imaging Reporting and Data System. Using a commercially available AI-CAD (Lunit INSIGHT for Mammography, Lunit Inc.), quantitative abnormality scores of 0 to 100% of the ipsilateral breast were obtained. Data were collected on age at diagnosis, symptoms, biopsy methods, DCIS grade on biopsy, and presence or absence of invasive cancer and axillary lymph node metastases on surgical pathology. Multivariable logistic regression models were used to evaluate factors associated with prediction of occult invasive cancer. Results: Of 692 biopsy-proven DCIS in 692 women (mean age, 53 years ± 11 [standard deviation]), 298 (43%) presented as calcifications only, 160 (23%) as mass or asymmetry, and 111 (16%) as masses with calcifications. The other 123 (18%) cancers were not demonstrable on mammography. Surgical pathology revealed occult invasive cancer in 278 (40%) women and 18 (3%) had axillary metastasis. Women with occult invasive cancer showed higher abnormality scores on AI-CAD than women with pure DCIS (mean, 70% vs. 51%; P &amp;lt; .001), and women with axillary metastasis had higher abnormality scores on AI-CAD than women without axillary metastasis (mean, 88% vs. 58%; P = .002). High ( &amp;gt;75%) abnormality score on AI-CAD (Odds ratio [OR], 1.8 [95% CI: 1.3, 2.6]; P &amp;lt; .001), age of 55 years or higher (OR, 1.6 [95% CI: 1.2, 2.3]; P =.005), present symptoms in the ipsilateral breast (OR, 2.7 [95% CI: 1.9, 4.0]; P &amp;lt; .001), biopsy performed with a 14-gauge automated gun (OR, 2.5 [95% CI: 1.7, 3.6]; P &amp;lt; .001), and high-grade DCIS at biopsy (OR, 2.5 [95% CI: 1.7, 3.5]; P &amp;lt; .001] were independent predictors of occult invasive cancer with a C-index of 0.75 (95% CI: 0.72, 0.78). Conclusion: The quantitative score of preoperative mammography obtained from a commercially available AI-CAD was able to predict occult invasive cancer in an easy and simple manner. AI-CAD applications for preoperative mammography may be useful in predicting occult invasive cancer in women with biopsy-proven DCIS, especially in those without preoperative breast MRI. Citation Format: Su Hyun Lee, Hajung Kim, Su Min Ha, Soo-Yeon Kim, Jung Min Chang, Nariya Cho, Woo Kyung Moon. Artificial Intelligence-based Computer-aided Diagnosis for Mammography: Predicting Occult Invasive Cancer in Women with Biopsy-proven Ductal Carcinoma in Situ [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-28-07.

Abstract PO1-23-01: A novel nomogram for predicting the possibility of omitting axillary lymph node dissection after neoadjuvant chemotherapy for clinical node-positive breast cancer

Abstract Purpose: Currently, there is no validated strategy established for omitting axillary lymph node dissection (ALND), when axillary node metastases are expected to disappear with neoadjuvant chemotherapy (NAC) for clinical node-positive (cN+) breast cancers. In contrast, it was reported that the axillary pathological complete response (pCR) rate to NAC for cN+ breast cancer is approximately 40%. Therefore, it is necessary to develop a more accurate method for predicting nodal pCR (ypN0) to select patients who can omit ALND after NAC for cN+ breast cancer. Methods: This is a single-centered, retrospective clinical study conducted in 128 patients with cN+ primary breast cancer who underwent ALND after NAC between January 2014 and July 2021 at Saitama Medical Center. Clinical complete response (cCR) was defined as the disappearance of the primary tumor or axillary node metastasis, as confirmed by the findings of imaging. The pCR was defined as the absence of microscopic evidence of residual invasive carcinoma in primary breast tumor or axillary nodes. Clinicopathological variables were compared using Fisher’s exact test or logistic regression, as appropriate. Statistical significance was set at p&amp;lt; 0.05. Results: The median age of the patients was 52 years; 48.4% were premenopausal, 38.3% had cT3 or higher, 22.7% had cN2 or higher, and 50% had stage III disease. Estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) positivity accounted for the patients were 58.6%, 50%, and 31.3%, respectively. NAC included sequential taxanes and anthracyclines in 47.7% of the patients, and anti-HER2 therapy was used in all patients of HER2-positive breast cancer. Breast primary tumor cCR (ypT0) was 29.7% and ypN0 was 44.5%. The ypN0 rate was 19.5% higher than the ypT0 rate in all patients (p &amp;lt; 0.001); it was 4.8% higher in the luminal subtype (p=0.009), 25.5% higher in the triple-negative subtype (p &amp;lt; 0.001), and 29.3% higher in the HER2 subtype (p=0.015). Additionally, the ypN0 rate was 3.9% higher than the axillary node cCR (ycN0) rate in all patients (p &amp;lt; 0.001), 7.6% lower in luminal type (p &amp;lt; 0.001), 13.6% higher in triple-negative type (p &amp;lt; 0.001), and 5% higher in the HER2 subtype (p=0.006). When ycN0 was predicted to be ypN0, the negative predictive value (NPV) was 77.2% and the false negative rate (FNR) was 19.7% (Table 1). In the association between ypN0 and preoperative clinico-pathological factors in cN+ breast cancer treated with NAC, univariate analysis showed significant differences in ER negativity (ER-) [hazard ratio (HR): 0.186, 95% confidence interval (CI): 0.086–0.401, p&amp;lt; 0.001], PgR negativity (HR: 0.360, 95% CI: 0.176–0.736, p=0.005), HER2 positivity (HER2+) (HR: 4.394, 95% CI: 1.941–9.949, p&amp;lt; 0.001), ycT0 (HR: 10.667, 95% CI: 4.020–28.304, p&amp;lt; 0.001), and ycN0 (HR: 9.966, 95% CI: 4.399–922.576, p&amp;lt; 0.001). The multivariate analysis revealed that ER, ycT0, and ycN0 were independent predictive factors for ypN0 after NAC in the patients with cN+ breast cancer (Table 2). These independent factors in multivariate analysis were used to create a nomogram for ypN0 prediction. The points added were 82 if the patient was ER-, 56 if the patient was ycT0, and 100 if the patient was ycN0, and the total of these scores was used to predict whether the patient had ypN0. When the Receiver Operating Characteristic curve was used to determine the cut-off value of the total points, 119 or more points were predicted to be ypN0, the NPV was 92.9%, and the FNR was 4.5%, which demonstrated an approximately 15% improvement over the prediction of ypN0 by ycN0 alone (Table 3). Conclusion: ER, ycT0, and ycN0 are independent predictive factors of ypN0 in cN+ breast cancer, suggesting that ypN0 prediction using a nomogram may contribute to individualized axillary treatment. Table 1. Accuracy of ypN0 prediction with ycN0 after NAC for clinical node-positive breast cancer Table2. Univariate and multivariate analyses of the relationship between preoperative clinicopathological factors and pathologically axillary node-negative after neoadjuvant chemotherapy in clinical node-positive breast cancer Table 3. Accuracy of ypN0 prediction after NAC for clinical node-positive breast cancer using Nomogram Citation Format: Hirohito Seki, Yuki Ishiguro, Ken Shimizu, Akitsugu Makino, Yoshiharu Ishizaka, Ai Tsuchiya, Hirotsugu Isaka, Shigeru Imoto. A novel nomogram for predicting the possibility of omitting axillary lymph node dissection after neoadjuvant chemotherapy for clinical node-positive breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-23-01.

Abstract PO5-05-13: Clinical utility of whole body low dose computed tomography for detecting bone metastasis in breast cancer patients: A cross sectional study

Abstract Clinical utility of Whole Body Low Dose CT scan for detecting bone metastasis in Breast cancer patients: A cross sectional study Background: Skeletal scintigraphy (Bone scan) is the imaging of choice to detect bone metastasis in locally advanced and metastatic breast cancer patients. Nuclear medicine facilities are however limited in their availability. As an alternative diagnostic modality to bone scan, we studied the diagnostic capability of Whole-Body Low Dose CT (WBLDCT) scan for detection of bone metastasis in these patients. Materials and Method: This cross-sectional study was conducted from November 2021 to May 2023 at a tertiary healthcare center in India with an aim to study the clinical applicability of whole-body low dose computed tomography scan for detecting bone metastasis in patients with breast cancer. Breast cancer patients with primary tumor measuring 5cm or more, pathologically proven axillary lymph node metastasis, Stage III/IV disease, symptoms attributable to metastasis and suspected disease recurrence were included. All patients underwent WBLDCT and Bone scan within a period of about 2 weeks. WBLDCT was done during the same time as conventional dose CT scan was being done as part of metastatic workup. WBLDCT acquisition protocol was set in CT scan machine by modulating the technical parameters like Care dose 4D-automated, Care kV semi, rotation time &amp; noise index. The image analysis was performed by Radiologist and Nuclear medicine experts in a blinded fashion. Data was recorded in MS Excel sheet. Sensitivity, specificity, positive and negative predicative value, and concordance rates were calculated using SPSS software ver 25.0. Agreement amongst WBLDCT and Bone scan was calculated using Inter-rater agreement. p value &amp;lt; 0.05 was taken as significant. Results: 110 patients were enrolled in this study. The mean age of participants was 48.5 years and three fourth had stage III disease at presentation. Estrogen receptor positive disease was seen in 43.64% participants while 30% were triple negative. Her2neu positive disease was seen in 27.27% patients. Bone scan couldn’t be done in 03 patients who deferred treatment (these had no bone metastasis on WBLDCT). Both bone scan and WBLDCT detected bone metastasis in 19 patients. Bone scan picked up additional metastasis in three patients which were missed on WBLDCT. WBLDCT detected bone metastasis additionally in three patients which were not detected on Bone scan. Multiple lesions were most seen in vertebrae in 38.5% and 28.6% on bone scan and WBLDCT respectively. The sensitivity and specificity of WBLDCT for detection of bone metastasis was 86.36% and 96.47% respectively. The concordance rate between Bone scan and WBLDCT scan was 94.39% with an Inter-rater Kappa(k) quotient for agreement of 0.828 (p&amp;lt; 0.0001). Conclusion: WBLDCT scan has comparable diagnostic capability to skeletal scintigraphy in detecting bone metastasis in breast cancer and may be a useful alternative specially in resource limited settings. Table 1: Sensitivity, specificity, positive predictive value and negative predictive value of WBLDCT for detection of metastasis Variables Values Sensitivity (95% CI) 86.36% Specificity (95% CI) 96.47% AUC (95% CI) 0.91 Positive Predictive Value (95% CI) 86.36% Negative Predictive Value (95% CI) 96.47% Diagnostic accuracy 94.39% Inter-rater agreement (kappa) 0.828 Citation Format: Lipton Mitra, Suhani Suhani, Ankur Goyal, Rakesh Kumar, Mohit Joshi, Hemanga Bhattacharjee, Haresh KP, Raju Sharma, Rajinder Parshad. Clinical utility of whole body low dose computed tomography for detecting bone metastasis in breast cancer patients: A cross sectional study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-05-13.

Abstract PO4-27-10: A Systematic Review and Meta-analysis of Diagnostic Performance of Fluorescein Guided Sentinel Lymph Node Biopsy in Early Breast Cancer

Abstract Background: Evaluation of axillary lymph nodes status in cN0 axilla is performed by sentinel lymph node biopsy (SLNB) utilizing a combination of radioactive isotope and blue dye. There is a paucity of radioactive tracer in many countries of transitional economies. Hence, alternatives to isotope have been explored, viz. indocyanine green (ICG), superparamagnetic iron oxide nanoparticles and Fluorescein Sodium (FS). This systematic review and meta-analysis, evaluates the diagnostic performance of Fluorescein Sodium guided SLNB. Objectives: The objective was to evaluate the diagnostic performance of Fluorescein Sodium for sentinel lymph node biopsy in early breast cancer. Methods: PRISMA 2020 guidelines were followed for this meta-analysis. Eligibility criteria: Studies where SLNB was performed using Fluorescein Sodium for breast carcinoma. Information sources: PubMed, EMBASE, Cochrane library and online clinical trial registers Risk of bias: Articles were assessed for risk of bias using the QUADAS-2 tool. Synthesis of results: The main summary measures were pooled detection rate and pooled false negative rate using random effects model. In order to describe heterogeneity, we constructed summary receiver operating characteristic (SROC) curves with 95% prediction regions, estimated using bivariate meta-analysis with a test level random effect only, and forest plots. Calculations were performed using the Meta-Disc v1.4 program (available from https://metadisc.software.informer.com/1.4/). Results: Out of 45 studies found on initial systematic search, 7 studies were found eligible and were included in the meta-analysis based on data on 332 patients. The pooled detection rate was 93.2% (95% confidence interval [CI] 87% to 97%).). The heterogeneity (I2 value) of the pooled detection rate was 71%. Five validation studies were included for pooling the false negative rate (FNR) and included a total of 211 patients. The pooled FNR was 5.6% (95% CI; 2.9 to 9.07). Five validation studies were included for sensitivity, specificity, diagnostic odds ratio, LR+ and LR- meta-analysis. With regards to the identification of SLN the pooled sensitivity was 80% [(95% CI, 68% to 89%); I2=79.8]; specificity was 98% [(95% CI, 95% to 100%); I2=0.0]. The likelihood ratio for a positive test LR+ was 23.2 [(95% CI, 5.91 to 95.18); I2=0.0] and likelihood ratio for a negative test a LR- of 0.41 [(95% CI, 0.16 to 1.05); I2=88.1]. The diagnostic Odds ratio OR was 76.94 (95% CI, 15.88 to 372.79). Diagnostic accuracy as measured by SROC was 99.08%. Q index was 0.96. Publication bias for pooled detection rate as per Egger’s test was -2.2 (p= 0.66) and for FNR was 1.85 (p=0.29). Visual inspection of summary ROC curve and of forest plots did not show significant heterogeneity. Conclusion: Fluorescein guided SLNB is an affordable option for detection of lymph node metastases in cN0 patients with early breast cancer. It achieves a high detection rate of 93% with a false negative rate of 5.6% for the detection of axillary lymph node metastasis. We recommend larger multinational trials to confirm its high detection rate with low false negativity. Citation Format: Sanjay Kumar Yadav, Bharath S, Sarada Khadka, Dhananjaya Sharma, Chandan Kumar Jha, Gaurav Agarwal, Manju Singh, Anurag Srivastava, Amit Goyal. A Systematic Review and Meta-analysis of Diagnostic Performance of Fluorescein Guided Sentinel Lymph Node Biopsy in Early Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-27-10.

Abstract PO4-19-04: AXSANA – EUBREAST-3: An international prospective multicenter cohort study to evaluate different surgical methods of axillary staging in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy

Abstract Background The optimal surgical staging procedure of the axilla in patients who convert from a clinically positive (cN+) to a clinically negative node status (ycN0) through neoadjuvant chemotherapy is still controversial. Widely diverse techniques such as full Axillary Lymph Node Dissection (ALND), Targeted Axillary Dissection (TAD), Targeted Lymph Node Biopsy (TLNB) and Sentinel Lymph Node Biopsy (SLNB) alone are given preference in different international guidelines. So far, no comparative data on the oncological outcome or the morbidity of the different procedures are available. Further research is needed to safely de-escalate the extent of axillary surgery in this patient group. Trial design The AXSANA study is an international prospective cohort study including cN+ patients converting to ycN0 status and treated with different axillary staging techniques according to the standard at their treating institution. The study was initiated by the EUBREAST network. The trial includes patients with cT1-4c tumors, who present initially with axillary lymph node metastasis scheduled for neoadjuvant chemotherapy. According to an amendment in 2020 the inclusion of patients with highly suspicious nodes without confirmation using a minimally invasive biopsy is allowed. All patients converting to ycN0 status undergo follow-up for 5 years irrespectively of the ypN status. Primary endpoints: Invasive disease-free survival, axillary recurrence rate and health-related quality of life (HRQoL). HRQoL are evaluated using four standardized questionnaires (EORTC QLQ-C 30, EORTC QLQ-BR 23, Lymph ICF and SOC-13) at baseline and after 1, 3 and 5 years after surgery. Secondary endpoints are the feasibility and performance of different axillary staging techniques (detection rate, number of removed lymph nodes and association with complications, arm morbidity and quality of life, operating time and use of clinical and economic resources); impact of learning curve, and the detailed mapping of surgical and oncological treatment standards in different countries. The impact on different regional treatment strategies (radiotherapy, ALND) in patients with ypN0(i+), ypN1(mi) and ypN1 is assessed. Current status of the study: 4336 patients from 284 study sites and 26 countries were enrolled in the study between June 2020 and June 2023. Among 3722 patients with a defined surgical concept 1631 women were scheduled for TAD, 1483 for ALND, 469 for SLNB, 25 for TLNB and 109 for other procedures. A target lymph node was marked in 2309 patients, most frequently using clips/coils (1850, 80.1%), followed by magnetic seeds (219, 9.5%), carbon ink (171, 7.4%), radar marker (80, 3.5%), radioactive seeds (4, 0.2%) and other techniques (24, 1.0%). Funding: AGO-B, GBG, Claudia-von Schilling Foundation, Ehmann Foundation, Eugen und Irmgard Hahn Foundation, AWOgyn, Merit Medical, Endomagnetics, Mammotome Contact information: Prof. Dr. Thorsten Kühn Department of Gynecology and Obstetrics University of Ulm, Germany Baumreute 37 D-73730 Esslingen Germany E-Mail: kuehn.thorsten@t-online.de Citation Format: Thorsten Kühn, Steffi Hartmann, Elmar Stickeler, Jana de Boniface, Oreste Davide Gentilini, Sarah Fröhlich, Franziska Ruf, Marc Thill, Michael Hauptmann, Guldeniz Karadeniz Cakmak, Isabel Rubio, Maria Luisa Gasparri, Michalis Kontos, Eduard-Alexandru Bonci, Laura Niinikoski, Bilge Aktas Sezen, Rosa Di Micco, Dawid Murawa, Geeta Kadayaprath, David Pinto, Florentia Peintinger, Matilda Appelgren, Janine M. Simons, Marjolein Smidt, Ellen Schlichting, Lukas Dostalek, Elisabeth Thiemann, Markus Hahn, Michael Schrauder, Semra Gunay, Gunay Gurleyik, Nina Helidon, Hagigat Valiyeva, Ashutosh Kothari, Marian Vanhoeij, Andraz Perhavec, Tsvetomir Ivanov, Dov Zippel, Lia Rebaza, Sarun Thongvitokomarn, Sibylle Loibl, Maggie Banys-Paluchowski. AXSANA – EUBREAST-3: An international prospective multicenter cohort study to evaluate different surgical methods of axillary staging in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-19-04.

Abstract PO4-02-10: Predictive Factors of Nodal Upstaging at Time of Surgery in Clinically Node Negative Patients Undergoing Neoadjuvant Chemotherapy

Abstract Introduction: Neoadjuvant chemotherapy (NAC) can be given with the intent of downstaging breast cancer or to provide prognostic information prior to any surgical intervention in both node negative (N0) and node positive patients (pts). Residual nodal disease following neoadjuvant chemotherapy generally indicates poorer overall prognosis relative to those who are node negative. Several risk factors have been postulated to predict the presence of occult lymph node metastasis: age at diagnosis, tumor size, status of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor (HER-2), and BMI. NAC has been shown to eradicate axillary lymph node metastasis in up to 40% of pts. This study aims to evaluate characteristics of clinically N0 pts who underwent NAC and were upstaged to node positive status at the time of surgery. We hope to identify patient related factors that may help predict the presence of occult nodal disease as well compare pathological complete response rate (PCR) in the breast between N0 and patients who were upstaged. Methods: Data was collected through retrospective chart review of the Stroger Cook County electronic medical records system (CERNER). Pts treated at John H. Stroger Hospital from 2017-2021 with a new diagnosis of cT2-T3 invasive breast cancer who were clinically and radiologically node negative and received NAC were included. We compared demographic data, staging information, cancer characteristics and pathologic complete response rates (PCR) in the breast between those who remained node negative and those who had positive sentinel lymph nodes at the time of surgery. Pts with prior breast cancer diagnosis and those who underwent treatments at an outside institution were excluded. Statistical analysis included 2-tailed t-test and 2-tailed fisher’s (p&amp;lt; 0.05). Results: A total of 98 pts were identified, 62 with complete data for analysis,11 were upstaged at the time of surgery. When comparing pts who had nodal upstaging to those that remained node negative at time of surgery there was no significant difference between average BMI (28.5), age of diagnosis (58 years). Most pts (73%) were T2 at presentation, of those with nodal upstaging at time of surgery, 20% were T3 or higher, while only 5% of those who were not upstaged at surgery were greater than T3 (NS). Upstaged pts had an average tumor size of 4.16 cm while non-upstaged on average were 2.85 cm (P&amp;lt; 0.01). ER positive pts (ER+) and PR positive (PR+) were more likely to have nodal upstaging post op (P&amp;lt; 0.0012, P&amp;lt; 0.0013) when compared to ER negative (ER-) and PR negative (PR-) respectively. The distribution of receptor status was significantly different between groups, the most common receptor status in upstaged patients was triple positive (63%) while triple negative was most common in non-upstaged (41%). Triple positive pts were more likely to be upstaged than those with other receptor statuses (64% vs 40%, p 0.0004). There was a 100% PCR rate in the breast among non-upstaged pts compared to 10% of upstaged patients (P&amp;lt; 0.0001). Among all triple negative pts, 42% had PCR, of ER-/PR-/HER2+, 60% had a PCR, ER+/HER 2 negative had a 40% PCR. Conclusion: Pts with larger presenting tumor size who are node negative at presentation and have undergone chemotherapy are more likely to have occult positive nodes at the time of surgery. ER positive pts and triple positive pts are also more likely to have occult positive nodes at time of surgery. While our sample is small, our breast PCR rate is consistent with other published literature. Further investigation confirming this with larger samples and multi-institutional investigation may help to establish these relationships and elucidate a predictive model. The optimal management of these patients is worthy of further study. Citation Format: Rangel Melissa, Julia Alexieva, Alison Coogan, Elizabeth Marcus, Julie Wecsler. Predictive Factors of Nodal Upstaging at Time of Surgery in Clinically Node Negative Patients Undergoing Neoadjuvant Chemotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-02-10.

Abstract PS05-01: Accuracy and safety of fibroblast activation protein inhibitor (FAPI) PET/CT in diagnosis of axillary lymph node metastasis in early breast cancer patients: a prospective cohort study (PFB-01&amp;02 study)

Abstract Background Axillary lymph node (ALN) is the most common metastatic site of breast cancer (BC) and the status of ALN determines the staging, treatment and prognosis for BC patients. Traditional imaging techniques, including ultrasound (US), mammography, MRI, and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) were still unsatisfactory to evaluate the status of ALN non-invasively. Fibroblast activation protein (FAP) is highly expressed in cancer-associated fibroblasts and FAP inhibitor (FAPI) PET has been found quite promising in BC. Well-designed prospective large cohort study concerning the diagnostic performance and safety profile of FAPI PET/CT in detection of ALN metastasis of BC is still lacking. Furthermore, FAPI could be radio-labeled with different radio-nuclides including 68Ga and 18F, and there is yet no data concerning the 18F-labeled FAPI in BC. In this study, we investigated the accuracy of FAPI (both 68Ga-FAPI-04 and Al18F-FAPI-04) PET/CT in newly diagnosed BC patients for assessing ALN metastasis. We also compared the diagnostic performance of FAPI PET/CT with that of 18F-FDG PET/CT and US. Methods This prospective study was approved by the Peking Union Medical College Hospital Ethics Committee and was registered online at NIH ClinicalTrials.gov (NCT05574907, NCT05574920). The inclusion criteria were as follows: (1) age 18-80 years old; (2) newly diagnosed BC confirmed by biopsy or with BI-RADS category 4C or 5 lesions by US. The exclusion criteria were as follows: (1) pregnancy or lactation; (2) patients unwilling to undergo PET/CT scans. All patients received biopsy or surgery on breast lesion and ALN. Patients received FAPI and 18F-FDG PET/CT after enrollment. The safety profile of FAPI PET was monitored after injection using the Common Terminology Criteria for Adverse Events. Two experienced nuclear medicine physicians, who were blinded to the pathological diagnosis and other imaging results, assessed the PET/CT images. It was defined as visually positive if the radioactive uptake of the ALN was higher than that of the adjacent normal tissue. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each diagnostic test. The McNemar test was applied to compare the differences of sensitivity and specificity between FAPI PET/CT, 18F-FDG PET/CT, and US. All statistical tests were performed two-sided, and P&amp;lt; 0.05 was considered statistically significant. Results In total, 113 patients (27-79 years old, median age 66) were enrolled. 53 patients underwent 68Ga-FAPI-04 PET/CT, and the other 60 patients underwent Al18F-FAPI-04 PET/CT. All patients underwent 18F-FDG PET/CT and US. A total of 53/113 (46.9%) patients were finally diagnosed with ALN metastasis. The sensitivity, specificity, accuracy, PPV, and NPV were 90.6%, 90.0%, 90.3%, 88.9%, and 91.5% for FAPI PET/CT, 84.9%, 73.3%, 78.8%, 73.8%, and 84.6% for 18F-FDG PET/CT, 83.0%, 76.7%, 79.6%, 75.9%, and 83.6% for US, respectively (Table 1). The specificity of FAPI PET/CT was significantly higher than that of 18F-FDG PET/CT (P &amp;lt; 0.05) and US (P &amp;lt; 0.05). The sensitivity of FAPI PET/CT was higher than that of 18F-FDG PET/CT (P= 0.45) and US (P= 0.29). There was no significant difference of sensitivity and specificity between 18F-FDG PET/CT and US (P &amp;gt; 0.05). The sensitivity, specificity, accuracy, PPV, and NPV were 92.0%, 92.9%, 92.5%, 92.0%, and 92.9% for 68Ga-FAPI-04 PET/CT, and 89.3%, 87.5%, 88.3%, 86.2%, and 90.3% for Al18F-FAPI-04 PET/CT, respectively (Table 2). The 68Ga-FAPI-04 PET/CT and Al18F-FAPI-04 PET/CT procedures were well tolerated in all patients. The only adverse event was injection pain in 12/53 (22.6%) patients injected with 68Ga-FAPI-04, and 7/69 (10.1%) patients injected with Al18F-FAPI-04, which might relate to the ethanol in the imaging agent. Conclusion The FAPI PET/CT outperformed 18F-FDG PET/CT and US in the diagnosis of ALN metastasis among early breast cancer patients. The 68Ga-FAPI-04 and Al18F-FAPI-04 PET/CT have similar diagnostic performance. The FAPI PET/CT procedures were well tolerated in all patients. Table 1 Diagnostic performance of FAPI PET/CT, 18F-FDG PET/CT, and ultrasound in the diagnosis of ALN metastasis Table 2 Diagnostic performance of 68Ga-FAPI-04 and Al18F-FAPI-04 PET/CT in diagnosis of ALN metastasis Citation Format: Bo Pan, Zhixin Hao, Chao Ren, Lifan Zhang, Yidong Zhou, Qiang Sun, Li Huo. Accuracy and safety of fibroblast activation protein inhibitor (FAPI) PET/CT in diagnosis of axillary lymph node metastasis in early breast cancer patients: a prospective cohort study (PFB-01&amp;02 study) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS05-01.

Survival After Contralateral Axillary Metastasis in Breast Cancer.

Despite stage IV categorization, survival outcomes for breast cancer patients who experience contralateral axillary lymph node metastasis (CAM) remain uncertain. This study aimed to investigate the clinical outcomes for patients with metachronous CAM to provide insights into its prognosis and treatment recommendations. This study retrospectively reviewed medical records of patients who underwent curative surgery for breast cancer and experienced CAM as the first site of distant metastasis (DM) during the follow-up period between January 2001 and April 2023. Survival outcomes of the CAM patients were compared with those of breast cancer patients with other DM via propensity score-matching (PSM). The study identified 40 breast cancer patients with metachronous CAM. The estimated 5-year overall survival (OS) was 39.6%, and the progression-free survival was 39.4%. The patients with CAM exhibited marginally better OS than the patients with DM (p = 0.071), but survival similar to that of the patients with isolated supraclavicular node recurrence (SCN) (p = 0.509). Moreover, matching of CAM with DM using two PSM models showed a consistently insignificant survival difference (hazard ratio [HR], 1.47; p = 0.124 vs. HR, 1.19; p = 0.542). Ipsilateral breast tumor recurrences (IBTRs) were experienced by 12 patients before or concurrently with the CAM. These patients exhibited significantly better survival than the remaining patients (HR, 0.28; p = 0.024). The breast cancer patients with CAM showed survival similar to that for the patients with DM, supporting the current stage IV classification of the CAM. However, CAM associated with IBTR exhibited superior survival outcomes, suggesting that this subset of CAM may benefit from treatments with curative intent.

Abstract PO3-17-09: Outcome after the introduction of personalized treatment for axilla in patients with clinically node-negative early breast cancer

Abstract Background : After the results of ACOSOG Z0011 and AMAROS trials were reported, axillary treatment has been promoted to de-escalation. For clinically negative cases of axillary lymph node metastasis (cN0), axillary dissection (Ax) has been the standard treatment when sentinel lymph node (SN) metastasis is positive. In our hospital, for patients with cN0, if SN macro metastasis is positive, Ax or irradiation (RT) is selected after sufficient explanation to the patients. Five years have passed since the introduction of treatment selection for the axilla, we examined treatment outcomes retrospectively. Methods : The subjects were 1376 patients who underwent SN biopsy for primary breast cancer with cN0 at our hospital from October 2004 to December 2018 (median observation period 79 months). Cases who underwent preoperative chemotherapy were excluded. We have introduced the treatment choice system since December 2015, and compared prognosis (local recurrence, distant recurrence and breast cancer specific death) before and after introduction using the log-rank test. Results : There were 947 cases before introduction of treatment choice system (pre group) and 429 cases after introduction (post group). The median observation period for each group was 91 months and 41 months. The maximum observation period post group was 67 months, then we compared the number of events in patients with observation period less than 67 months in pre group. There was no significant difference between two groups (Pre/Post) in terms of age (p=0.52), menopausal status (p=0.90), invasion of primary lesion (p=0.19), biology and SN metastasis status (p=0.41). There were 54 patients (12.6%) in pre group and 135 (14.3%) patients in post group had positive sentinel lymph nodes. In post group, 33 patient (61.1%) were macrometastasis of SN, 28 of whom underwent Ax and 5 underwent RT. Local recurrence was 4 cases (1.7%) in pre group, 9 cases (2.1%) in post group (p=0.84), distant recurrence was 13 cases (5.6%) and 5 cases (1.2%) (p=0.0002), and breast cancer specific death was 8 cases (0.8%) and 1 case (0.2%) (p=0.0003), respectively. Discussion : There was no significant difference in local recurrence rate within 67 months, but were poor prognosis in pre introduction group for distant metastasis and breast cancer specific survival. In the results of this study, there was no significant difference in local recurrence, but the prognosis for distant recurrence and breast cancer-specific death was poor in the before introduction group. The median observation period in the post introduction group was 47 months, and late recurrence of ER-positive breast cancer occurs later. It is necessary to continue the study by extending period and accumulation cases. Conclusion : For cN0 cases, if the case is suitable, we introduced the treatment choice system that allows omitting Ax by performing radiotherapy in SN macrometastasis positive patients. After introduction, there was no increase in the relapse rate after introduction in the short term. Appropriate case selection allowed the safety introduction of individualizes treatment for axilla. Citation Format: Mai Tomiguchi, Kaori Hidaka, Lisa Goto-Yamaguchi, Ayako Kajiwara, Kanako Nishikido, Toko Inao, Yutaka Yamamoto. Outcome after the introduction of personalized treatment for axilla in patients with clinically node-negative early breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-17-09.

Abstract PS05-03: MagSense® HER2, a Molecularly Targeted Magnetic Resonance Imaging Agent for the Detection of Axillary Nodal Metastasis in Subjects with Human Epidermal Growth Factor Receptor 2 Positive (HER2+) Breast Cancer

Abstract Background Precise nodal staging is critical in guiding systemic and regional treatments including surgery in the management of breast cancer. Regional nodal assessment includes axillary imaging (mostly by ultrasound) and lymph node sampling. Since imaging findings suggestive of nodal metastasis are based on size and morphologic changes and not specific to tumor type, pathologic confirmation through either biopsy or removal of sentinel lymph node (SLN) remains the gold standard. Imagion is developing the MagSense® HER2 Imaging Agent (MSH2IA), an anti-human epidermal growth factor receptor 2 (HER2) conjugated with iron oxide nanoparticles, for the detection of nodal metastasis in HER2+ breast cancer patients. MSH2IA is currently being investigated in a first-in-human phase 1 study (ACTRN12621000126819) in HER2+ breast cancer patients who are diagnosed to have suspicious nodes by conventional imaging. Methods The key objectives of the phase 1 study are safety and tolerability of MSH2IA and confirmation that MSH2IA drains to the axillary lymph nodes. The study also explores MSH2IA’s ability to detect metastatic nodes when used with magnetic resonance imaging (MRI), with tumor status assessed by standard tissue histopathology. All eligible subjects receive a 22.5 mg (iron equivalent) subareolar or peritumoral injection of MSH2IA. MRI of the axilla are obtained before and 24 to 72 hours after MSH2IA injection. Core biopsy or dissection of a node suspicious by ultrasound is obtained for histopathology assessments. After completing the first cohort of 6 subjects, the protocol was amended to include the insertion of an MRI compatible clip in a node suspicious by ultrasound to localize the suspicious node for core biopsy and postdose MRI scan. Review of MRI scans and histopathology are performed in respective central laboratories. Results Thirteen participants with HER2+ breast cancer have completed the study. MSH2IA appears safe and well tolerated. The imaging agent, as administered, is detectable by MRI and pathology, confirming that MSH2IA drains to the lymph nodes via the chosen route of administration. In postdose MRI scans, study central radiologists reported distinct and differentiable MRI appearance in morphologically normal and suspicious nodes. The presence of a distinct postdose MR image appearance was confirmed by a group of independent radiologists in a separate blinded review. While normal nodes appeared with homogeneous hypointensity, morphologically suspicious nodes showed partial irregular darkening and/or speckled heterogeneous hypointensity. In evaluable subjects, histopathology of the core biopsies obtained from the clipped nodes confirmed the presence of HER2+ nodal metastasis, providing preliminary evidence for node-level concordance between MRI vs pathology observations. Safety, imaging, and pathology results from all available subjects will be presented. This phase 1 study in Australia will be closing enrollment by July 31, 2023. A phase 2 study in the United States and elsewhere is being planned with the objectives of optimizing dose, schedule, and imaging parameters for best diagnostic performance for clinical utility. Conclusion Available data from the ongoing phase 1 study show that MSH2IA appears safe and drains to the axillary lymph nodes. MSH2IA displays a distinct and differentiable MRI appearance in nodes morphologically highly suspicious for tumor, which is confirmed to be HER2+ metastasis by histopathology by node level concordance. This data provides preliminary proof of principle for the mechanism of molecularly targeted MR imaging and suggests that MSH2IA has the potential to provide tumor-specific MR imaging not currently available in conventional axillary imaging. Citation Format: Jane Fox, Shanta Velaiutham, Natalie Yang, Eddie lau, Kowsi Murugappan, Beena Kumar, Alex Laslowski, Koushik Govindarajan, Steven Reich, Stephen Thomas, Nitika Neha, Marie Zhang, Isaac Bright. MagSense® HER2, a Molecularly Targeted Magnetic Resonance Imaging Agent for the Detection of Axillary Nodal Metastasis in Subjects with Human Epidermal Growth Factor Receptor 2 Positive (HER2+) Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS05-03.

Clinical and Imaging Characteristics of Contrast-enhanced Mammography and MRI to Distinguish Microinvasive Carcinoma from Ductal Carcinoma In situ

Rationale and ObjectivesThe prognosis of ductal carcinoma in situ with microinvasion (DCISM) is more similar to that of small invasive ductal carcinoma (IDC) than to pure ductal carcinoma in situ (DCIS). It is particularly important to accurately distinguish between DCISM and DCIS. The present study aims to compare the clinical and imaging characteristics of contrast-enhanced mammography (CEM) and magnetic resonance imaging (MRI) between DCISM and pure DCIS, and to identify predictive factors of microinvasive carcinoma, which may contribute to a comprehensive understanding of DCISM in clinical diagnosis and support surveillance strategies, such as surgery, radiation, and other treatment decisions. Materials and MethodsForty-seven female patients diagnosed with DCIS were included in the study from May 2019 to August 2023. Patients were further divided into two groups based on pathological diagnosis: DCIS and DCISM. Clinical and imaging characteristics of these two groups were analyzed statistically. The independent clinical risk factors were selected using multivariate logistic regression and used to establish the logistic model [Logit(P)]. The diagnostic performance of independent predictors was assessed and compared using receiver operating characteristic (ROC) analysis and DeLong's test. ResultsIn CEM, the maximum cross-sectional area (CSAmax), the percentage signal difference between the enhancing lesion and background in the craniocaudal and mediolateral oblique projection (%RSCC, and %RSMLO) were found to be significantly higher for DCISM compared to DCIS (p = 0.001; p < 0.001; p = 0.008). Additionally, there were noticeable statistical differences in the patterns of enhancement morphological distribution (EMD) and internal enhancement pattern (IEP) between DCIS and DCISM (p = 0.047; p = 0.008). In MRI, only CSAmax (p = 0.012) and IEP (p = 0.020) showed significant statistical differences. The multivariate regression analysis suggested that CSAmax (in CEM or MR) and %RSCC were independent predictors of DCISM (all p < 0.05). The area under the curve (AUC) of CSAmax (CEM), %RSCC (CEM), Logit(P) (CEM), and CSAmax (MR) were 0.764, 0.795, 0.842, and 0.739, respectively. There were no significant differences in DeLong's test for these values (all p > 0.10). DCISM was significantly associated with high nuclear grade, comedo type, high axillary lymph node (ALN) metastasis, and high Ki-67 positivity compared to DCIS (all p < 0.05). ConclusionThe tumor size (CSAmax), enhancement index (%RS), and internal enhancement pattern (IEP) were highly indicative of DCISM. DCISM tends to express more aggressive pathological features, such as high nuclear grade, comedo-type necrosis, ALN metastasis, and Ki-67 overexpression. As with MRI, CEM has the capability to help predict when DCISM is accompanying DCIS.

The use of longitudinal CT-based radiomics and clinicopathological features predicts the pathological complete response of metastasized axillary lymph nodes in breast cancer

BackgroundAccurate assessment of axillary status after neoadjuvant therapy for breast cancer patients with axillary lymph node metastasis is important for the selection of appropriate subsequent axillary treatment decisions. Our objectives were to accurately predict whether the breast cancer patients with axillary lymph node metastases could achieve axillary pathological complete response (pCR).MethodsWe collected imaging data to extract longitudinal CT image features before and after neoadjuvant chemotherapy (NAC), analyzed the correlation between radiomics and clinicopathological features, and developed models to predict whether patients with axillary lymph node metastasis can achieve axillary pCR after NAC. The clinical utility of the models was determined via decision curve analysis (DCA). Subgroup analyses were also performed. Then, a nomogram was developed based on the model with the best predictive efficiency and clinical utility and was validated using the calibration plots.ResultsA total of 549 breast cancer patients with metastasized axillary lymph nodes were enrolled in this study. 42 independent radiomics features were selected from LASSO regression to construct a logistic regression model with clinicopathological features (LR radiomics-clinical combined model). The AUC of the LR radiomics-clinical combined model prediction performance was 0.861 in the training set and 0.891 in the testing set. For the HR + /HER2 − , HER2 + , and Triple negative subtype, the LR radiomics-clinical combined model yields the best prediction AUCs of 0.756, 0.812, and 0.928 in training sets, and AUCs of 0.757, 0.777 and 0.838 in testing sets, respectively.ConclusionsThe combination of radiomics features and clinicopathological characteristics can effectively predict axillary pCR status in NAC breast cancer patients.