Node-negative Breast Cancer Research Articles

Recent Advances in the Tracer Technology Used for Sentinel Lymph Node Biopsy in Breast Cancer

The high incidence of breast cancer poses one of the greatest risks to female health worldwide. Sentinel lymph node biopsy (SLNB) is the standard of treatment for patients with axillary lymph node-negative early-stage breast cancer. Herein, the precise use of tracers is the key to ensuring the success of SLNB. However, owing to select-few limitations of traditional tracers, their clinical application is limited. New tracer techniques, such as the near-infrared fluorescent dye method (using indocyanine green), contrast-enhanced ultrasound, and superparamagnetic iron oxide nanoparticles are being applied in clinical practice. In this paper, we review the recent progress in SLNB tracer technology.

The diagnostic contribution of magnetic resonance imaging in the detection of axillary metastasis after neoadjuvant chemotherapy.

Sentinel lymph node dissection (SLND) is a reliable method that provides axillary staging in clinical node-negative (cN0) breast cancer patients before neoadjuvant chemotherapy (NACT). However, it is not a standard method on its own due to the high false-negative rates (FNR) reported in initially clinical node-positive patients (cN1-cN3). The contribution of magnetic resonance imaging (MRI) to SLND after chemotherapy is not well understood. In our study, we aimed to investigate the contribution of post-NACT MRI to SLND in breast cancer patients receiving NACT. Between January 2014 and December 2020, patients who had MRI images including the axilla after NACT and had axillary lymph nodes evaluation performed simultaneously with SLND were included in the study. MRI images of all patients were re-evaluated by 2 experienced clinicians. MRI and SLND results were analyzed to detect axillary lymph node metastasis. 117 patients were included in the study. The median age of the patients was 49 years. Before chemotherapy, 108 patients (92.3%) had tumor metastases in their axilla pathologically confirmed by tru-cut biopsy. Axillary downstage was obtained in 48.1% (n=52) of the patients after NACT. Of the 56 patients with axillary node positivity, 3 patients had no metastasis in the SLND evaluation (FNR=5.4%). The sensitivity of post-NACT MRI in detecting node positivity was 69.6%, the specificity was 90.2%, the positive predictive value (PPV) was 86.7% and the negative predictive value (NPV) was 76.4. SLND together with MRI predicted all node-positive patients (FNR=0%). In summary, SLND may not detect a group of patients with residual axillary lymph node metastases after NACT. We have shown that MRI can contribute to identifying these patients. If no metastases are detected by both methods (SLND and MRI), avoidance of axillary dissection may be an acceptable choice.

Study on intraoperative localization of sentinel lymph nodes using freehand SPECT in breast cancer patients.

The diagnostic and therapeutic approach to axillary lymph nodes is considered indispensable in the treatment of breast cancer patients. To investigate the effectiveness of 3D freehand SPECT (fhSPECT) in sentinel lymph node (SLN) mapping in breast cancer, compared with the use of a conventional gamma probe. We retrospectively compared the fhSPECT lymph node mapping modality, with gamma probe detection in early-stage, clinically node-negative breast cancer patients, with biopsy-confirmed malignancy. The two techniques were compared based on the average number of LNs excised per axilla. The duration of SLN mapping was also compared between the two groups. The performance of the two methods on obese and post-systemic therapy patients was evaluated. FhSPECT was used in 150 cases, while the gamma probe was employed in 50 cases. FhSPECT detected at least 3 nodes in 83.3% of the patients vs. 72.0% with the γ-probe (p = 0.107). The mean number of SLNs excised per axilla was 3.66 using the γ-probe and 4.18 with fhSPECT (p = 0.03). The average surgical time was 39 ±7 min with the γ-probe and 37.54 ±17 min with fhSPECT (p = 0.228). Sentinel lymph node biopsy (SLNB) mean surgical time evolved from 40.2 ±20.77 min to 32.35 ±10.46 min (p = 0.033). In obese patients, a reduction in surgical times was noted from 45.5 ±3.09 min to 44.04 ±20.9 (p = 0.27), in addition to a significant increase in average LN detection in the fhSPECT group (4.26 ±1.44) compared to the γ-probe group (3.2 ±1.65) (p = 0.043). The use of the fhSPECT modality is effective and safe, and, when compared to the γ-probe, has significant advantages in SLN mapping.

D-dimer as a safe, convenient and easily available biomarker, when combined with conventional sentinel node biopsy in clinically node negative breast cancer to assess metastatic disease in axilla and reduce false negative results

Background: Breast cancer is frequently associated with activation of the hemostatic system and the extent of this activation correlates with a more advanced tumor stage. D-dimer is a biomarker that indicates the activation of hemostasis and fibrinolysis.Methods: This is a prospective, observational, analytical study in which we compare plasma D-dimer levels among three groups’ i.e., healthy subjects, benign patients and breast cancer patients. We have also evaluated plasma D-dimer levels in patients with lymphadenopathy and in those patients who did not have palpable lymph nodes. Plasma D-dimer levels were further characterized based on TNM classification in breast cancer patients where quantitative D-dimer levels were correlated with clinical stage grouping.Results: Through our study we have observed that D-dimer level is inexpensive and a convenient method for diagnosis and prognosis of breast cancer. We have used a control group so as to evaluate a more accurate result. Comparison between benign and malignant lesions was made and we have achieved a significant p value, which proved our study positive for raised D-dimer levels in cancer breast.Conclusions: D-dimer proves to be a safe, convenient and easily available biomarker which can be combined with conventional sentinel node biopsy in clinically node negative breast cancer to assess metastatic disease in axilla and reduce false negative results. Plasma D-dimer level was positively correlated with clinical stage of solid cancers.

21-Gene Assay to Inform Chemotherapy Benefit in Node-Positive Breast Cancer

BackgroundThe recurrence score based on the 21-gene breast-cancer assay has been clinically useful in predicting a chemotherapy benefit in hormone-receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative, axillary lymph-node–negative breast cancer. In women with positive lymph-node disease, the role of the recurrence score with respect to predicting a benefit of adjuvant chemotherapy is unclear.MethodsIn a prospective trial, we randomly assigned women with hormone-receptor–positive, HER2-negative breast cancer, one to three positive axillary lymph nodes, and a recurrence score of 25 or lower (scores range from 0 to 100, with higher scores indicating a worse prognosis) to endocrine therapy only or to chemotherapy plus endocrine (chemoendocrine) therapy. The primary objective was to determine the effect of chemotherapy on invasive disease–free survival and whether the effect was influenced by the recurrence score. Secondary end points included distant relapse–free survival.ResultsA total of 5083 women (33.2% premenopausal and 66.8% postmenopausal) underwent randomization, and 5018 participated in the trial. At the prespecified third interim analysis, the chemotherapy benefit with respect to increasing invasive disease–free survival differed according to menopausal status (P=0.008 for the comparison of chemotherapy benefit in premenopausal and postmenopausal participants), and separate prespecified analyses were conducted. Among postmenopausal women, invasive disease–free survival at 5 years was 91.9% in the endocrine-only group and 91.3% in the chemoendocrine group, with no chemotherapy benefit (hazard ratio for invasive disease recurrence, new primary cancer [breast cancer or another type], or death, 1.02; 95% confidence interval [CI], 0.82 to 1.26; P=0.89). Among premenopausal women, invasive disease–free survival at 5 years was 89.0% with endocrine-only therapy and 93.9% with chemoendocrine therapy (hazard ratio, 0.60; 95% CI, 0.43 to 0.83; P=0.002), with a similar increase in distant relapse–free survival (hazard ratio, 0.58; 95% CI, 0.39 to 0.87; P=0.009). The relative chemotherapy benefit did not increase as the recurrence score increased.ConclusionsAmong premenopausal women with one to three positive lymph nodes and a recurrence score of 25 or lower, those who received chemoendocrine therapy had longer invasive disease–free survival and distant relapse–free survival than those who received endocrine-only therapy, whereas postmenopausal women with similar characteristics did not benefit from adjuvant chemotherapy. (Funded by the National Cancer Institute and others; RxPONDER ClinicalTrials.gov number, NCT01272037.)

Predicting oncotype DX recurrence scores using locally available immunohistochemical markers: experience in a district general hospital

AimsOncotype DX testing is a reliable widely used gene assay to determine whether chemotherapy is of additional value in oestrogen receptor (ER) positive Human Epidermal Growth Factor receptor 2 (HER2)...

Impact of TAILORx on chemotherapy prescribing and 21-gene recurrence score-guided treatment costs in a population-based cohort of patients with breast cancer.

The trial assigning individualized options for treatment (Rx) (TAILORx) confirmed the predictive value of the 21-gene recurrence score (RS) assay in hormone receptor (HR)-positive, HER2-negative, node-negative breast cancer and established thresholds for chemotherapy benefit in younger and older patients. Real-world chemotherapy use and RS-guided treatment costs in British Columbia post-TAILORx were examined. The authors assembled 3 cohorts of HR-positive, HER2-negative, node-negative patients with breast cancer defined by diagnosis: before RS funding (cohort 1 [C1]: January 2013-December 2013), after introduction of public RS funding (cohort 2 [C2]: July 2015-June 2016), and after TAILORx results (cohort 3 [C3]: July 2018-June 2019). Chemotherapy use was compared between cohorts by age and RS. Budgetary impacts of RS testing on chemotherapy costs were evaluated pre- and post-TAILORx. Among the 2066 patients included, chemotherapy use declined by 19% after RS funding was introduced and by an additional 23% after TAILORx publication (P = .001). Reduction in chemotherapy use was significant for RS 11-20 tumors (C3 vs C2, P = .004). There was no significant change in chemotherapy use in patients >50 years old (C2:12% vs C3:10%, P = .22). RS testing was associated with higher cost savings post-TAILORx, except in patients 70 to 80 years old, where testing led to excess costs when adjusting for the low rate of RS-concordant chemotherapy prescribed. TAILORx has had population-based impacts on chemotherapy prescribing in intermediate RS tumors and patients ≤50 years old. The lower clinical use of RS and increased spending in patients 70-80 years old highlights the importance of careful selection of older candidates for high-cost genomic testing. The 21-gene recurrence score (RS) test helps predict whether patients with hormone-positive, HER2-negative, lymph node-negative breast cancer are likely to benefit from chemotherapy. The recent trial assigning individualized options for treatment (Rx) (TAILORx) found that patients with intermediate RS tumors did not benefit from chemotherapy. The authors assessed whether TAILORx results translated to real-world changes in chemotherapy prescribing patterns. In this study, chemotherapy use decreased by 23% after TAILORx, with the greatest reductions seen among intermediate RS tumors and younger patients. In contrast, RS testing had lower clinical value and increased treatment costs in elderly patients, which requires further study to ensure optimal care for this age group.

Association Between Neutrophil-Lymphocyte Ratio and Oncotype Dx Recurrence Score in Early-Stage Hormonal Receptor-Positive, HER2-Negative, Node-Negative Breast Cancer.

PurposeThe correlation between the preoperative neutrophil-to-lymphocyte ratio (NLR) and Oncotype DX® (ODX) recurrence score (RS) has not yet been established. We aimed to investigate the association between NLR and ODX RS in patients with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2−) early-stage breast cancer (BC).Patients and MethodsThis retrospective study included consecutive patients with HR+/HER2−, node-negative primary BC who underwent surgical tumor resection from 2011 to 2019. Receiver operating characteristic curve analysis was used to obtain an optimal NLR cutoff value. Logistic regression analyses were used to estimate associations between various parameters and ODX RS. Furthermore, the factors significantly associated with the ODX RS in multivariable analysis were incorporated in a separate model and estimated using logistic regression.ResultsA total of 160 patients were enrolled. The optimal preoperative NLR cutoff was 2.15. Multivariable analysis revealed that NLR and tumor grade (G1/G2 vs G3) were independent predictive factors of high RS cutoff (≥26). Moreover, including the two variables yielded a stronger association; patients with low NLR and low-grade tumors were unlikely to have high RS (≥26; odds ratio [OR] = 0.03, 95% confidence interval [CI]: 0.006–0.154; p < 0.001). Conversely, the presence of any of the following factors made patients unlikely to have low RS (<16; OR = 0.34, 95% CI: 0.16–0.73; p = 0.006): high NLR, high grade, or high Ki-67 levels (>20).ConclusionNLR is a promising independent predictor of RS. Furthermore, in addition to tumor grade and Ki-67 level, they together are also a potential indicator of high and low RS. However, further studies are required to validate this hypothesis.

Efficacy of the Management of Node Negative Early Stage Breast Cancer Using 1% Methylene Blue in Sentinel Lymph Node Biopsy:prospective study, kasrAlaini University Hospital

Background:Accurate staging and proper management of axillary lymph nodes are important for the treatment of breast cancer. Sentinel lymph node biopsy (SLNB) provides accurate assessment of nodal status.Aimof work:Evaluation the safety, the accuracy and the cost of the application of SLNB using methylene blue 1% (MB 1%) in cases of node negative early stage breast cancer.Patients and methods:This study was conducted at Kasr Al-Ainy university Hospitals, Faculty of Medicine, Cairo University. Fifty-two female patients with node negative early stage breast cancer who agreed on undergoing breast conservative surgery( BCS), SLNB using 1% methylene blue and frozen section examination then managed according to ACOSOG Z0011 criteria .Results:Identification in 50 surgical specimens (identification rate 96.15%). By evaluating frozen section examination of the lymph nodes in relation to paraffin section examination we found that the sensitivity of the frozen section examination was 100% and specificity was 97.5% with positive predictive value 90.9%, negative predictive value 100% and overall accuracy was 98%.Conclusion:One % MB dye is very effective as a single agent in SLNB in node negative early stage breast cancer with very high identification rate compared to patent blue and radiocolloids. Implementation of ACOSOG Z0011 criteria proved its validity throughout our study as average 12 months follow up showed no locoregional recurrence

Hypofractionated whole breast radiation: how low can you go?

: Breast conserving therapy (BCT), consisting of breast conserving surgery (BCS) followed by whole breast radiation therapy (WBRT), is a well-established standard for the treatment of women with ductal carcinoma in situ (DCIS) and early-stage invasive breast cancer. While the original trials establishing this paradigm utilized conventionally fractionated (CF-WBRT) treatment delivered with daily fractions over 5–7 weeks, there is a significant amount of level I evidence in support of standardly using hypofractionated (HF-WBRT) regimens delivered over 3–4 weeks, and now there is data supporting even shorter courses. This article reviews the historical basis for CF-WBRT and subsequent radiobiological reasoning for attempting HF-WBRT. Summarized herein are the major clinical trials that have established the safety and efficacy of HF-WBRT as the standard of care in almost all women receiving BCT for early stage, node-negative breast cancer which form the basis of the American Society for Radiation Oncology (ASTRO) consensus statements. Completed and ongoing clinical trials that are attempting to establish the role of hypofractionated (HF) regimens for patients who require regional nodal irradiation as part of post-mastectomy radiation therapy (PMRT) are presented. Recently, published data on ultra-hypofractionated courses are reviewed. Finally, there is a discussion of adoption of hypofractionation globally. The goal of this review is to provide a rationale for the routine use of HF courses to improve patient access and convenience, healthcare resource utilization, and potentially decreasing patient exposure in the setting of the ongoing global pandemic.

Axillary Recurrence in Sentinel Lymph Node-Negative Breast Cancer Patients in a Tertiary Referral Cancer Centre

Axillary Recurrence in Sentinel Lymph Node-Negative Breast Cancer Patients in a Tertiary Referral Cancer Centre

Risk Factors, Prognostic Factors, and Nomogram for Distant Metastasis in Breast Cancer Patients Without Lymph Node Metastasis.

BackgroundLymph node negative (N0) breast cancer can be found coexisting with distant metastasis (DM), which might consequently make clinicians underestimate the risk of relapse and insufficient treatment for this subpopulation.MethodsThe clinicopathological characteristics of N0 breast cancer patients from the Surveillance, Epidemiology, and End Results (SEER) database between January 2010 and December 2015 were retrospectively reviewed. Multivariate logistic and Cox analyses were used to identify independent risk factors in promoting DM and the 1-, 3-, and 5- year cancer-specific survival (CSS) in this subpopulation.ResultSeven factors including age (<40 years), tumor size (>10 mm), race (Black), location (central), grade (poor differentiation), histology (invasive lobular carcinoma), and subtype (luminal B and Her-2 enriched) were associated with DM, and the area under curve (AUC) was 0.776 (95% CI: 0.763–0.790). Moreover, T1-3N0M1 patients with age >60 years at diagnosis, Black race, triple-negative breast cancer subtype, no surgery performed, and multiple DMs presented a worse 1-, 3-, and 5-year CSS. The areas under the ROC for 1-, 3-, and 5- year CSS in the training cohort were 0.772, 0.741, and 0.762, respectively, and 0.725, 0.695, and 0.699 in the validation cohort.ConclusionThe clinicopathological characteristics associated with the risk of DM and the prognosis of female breast cancer patients without lymph node metastasis but with DM are determined. A novel nomogram for predicting 1-, 3-, 5- year CSS in T1-3N0M1 patients is also well established and validated, which could help clinicians better stratify patients who are at a high-risk level for receiving relatively aggressive management.

Underutilisation of prophylactic G-CSF in breast cancer patients receiving adjuvant docetaxel/cyclophosphamide chemotherapy

Docetaxel/cyclophosphamide (TC) is a widely used adjuvant chemotherapy regimen, especially in patients with node-negative or low-risk node-positive breast cancer. Guidelines recommend the use of prophylactic granulocyte colony-stimulating factor (G-CSF) to prevent febrile neutropenia. In this study, we aimed to explore the use of G-CSF as a primary prophylactic and determine the factors influencing its use. This retrospective study used nationwide claims data from the National Inpatient Sample compiled by the Health Insurance Review and Assessment Service in South Korea from 2018. The claims data included 10% of inpatients admitted at least once in 2018 and 1% of outpatients who were not admitted. Female patients with breast cancer who received an adjuvant TC regimen after surgery were selected. Primary prophylactic G-CSF was defined as G-CSF prescribed within two days of the first cycle of TC. The factors influencing its utilisation were investigated using the chi-square test and a multiple logistic regression model. A total of 229 patients were included in the analysis. The proportion of patients who received primary prophylactic G-CSF treatment after the first cycle of TC was 55.5%. The factors positively influencing G-CSF utilization were patients’ age ≥65 years, location (i.e. metropolitan areas), and the type of healthcare facility (i.e. non-tertiary hospitals). The use of prophylactic G-CSF in patients with breast cancer who received the adjuvant TC regimen was insufficient. The use of primary G-CSF prophylaxis should be emphasised to reduce the risk of febrile neutropenia among patients receiving a myelosuppressive TC regimen.

Adjuvant treatment with paclitaxel plus trastuzumab for node-negative breast cancer: real-life experience.

Background: In node-negative HER2-overexpressedbreast cancers, adjuvant paclitaxel plus trastuzumab treatment is a successful de-escalation approach with excellent survival outcomes. Methods: All patients with HER2+ breast cancer treated in our centers were retrospectively reviewed. Results: We analyzed 173 patients who were treated with adjuvant paclitaxel plus trastuzumab. The mean tumor size was 2.2cm. There were eight invasive disease events or death: four distant recurrences (2.3%), three locoregional recurrences (1.7%)and one death without documented recurrence after a52monthfollow-up. The 3-year disease-free survival and recurrence-free interval rate was 96.6%. Conclusion: This real-life experience with adjuvant paclitaxel plus trastuzumab demonstrated few distant recurrences and iscompatible with theAPT trial findings.

Long-Term Survival Outcomes of Patients with Small (≤1 cm) Node-Negative HER2-Positive Breast Cancer Not Treated with Adjuvant Anti-HER2-Targeted Therapy: A 10-Year Follow-Up Study

Introduction: Human epidermal growth factor receptor 2 (HER2) expression is considered an unfavourable prognostic factor in early breast cancer when the patients are not treated with HER2-targeted therapy. However, the long-term prognostic importance of HER2 expression in small (≤1 cm, stage pT1a-b), node-negative HER2+ breast cancer is still incompletely known. Methods: A retrospective analysis was performed based on a prospectively collected database including patients with pT1 breast cancer operated at the Helsinki University Hospital, Finland, between March 2000 and April 2006. In this database, 44 patients with pT1a-bN0M0, HER2+ cancer, not treated with adjuvant anti-HER2-targeted therapy (the HER2+ group) and 291 pT1a-bN0M0, hormone receptor-positive, HER2-negative cancers (the ER+/HER2– group) were identified and included in the study. Survival outcomes were analysed using the Kaplan-Meier method. Results: The median follow-up time was 9.7 years after primary breast surgery. Ten-year distant disease-free survival (DDFS) was 84.0% in the HER2+ group and 98.2% in the ER+/HER2– group (p < 0.001). Ten-year overall survival was only 78.5% in the HER2+ group, but 91.7% in the ER+/HER2– group (p = 0.09). Conclusions: Cancer HER2 status is strongly associated with unfavourable DDFS during the first decade of follow-up in patients with small (pT1a-bN0M0) breast cancer when adjuvant anti-HER2-targeted treatment is not administered.

Disease Control After Hypofractionation Versus Conventional Fractionation for Triple Negative Breast Cancer: Comparative Effectiveness in a Large Observational Cohort

Questions remain about whether moderately hypofractionated whole-breast irradiation is appropriate for patients with triple-negative breast cancer. Using the prospective database of a multicenter, collaborative quality improvement consortium, we identified patients with node-negative, triple-negative breast cancer who received whole-breast irradiation with either moderate hypofractionation or conventional fractionation. Using inverse probability of treatment weighting (IPTW), we compared outcomes using the Kaplan-Meier product-limit estimation method with Cox regression models estimating the hazard ratio for time-to-event endpoints between groups. The sample included 538 patients treated at 18 centers in 1 state in the United States, of whom 307 received conventionally fractionated whole-breast irradiation and 231 received moderately hypofractionated whole-breast irradiation. The median follow-up time was 5.0 years (95% confidence interval [CI], 4.77-5.15 years). The 5-year IPTW estimates for freedom from local recurrence were 93.6% (95% CI, 87.8%-96.7%) in the moderate hypofractionation group and 94.4% (95% CI, 90.3%-96.8%) in the conventional fractionation group. The hazard ratio was 1.05 (95% CI, 0.51-2.17; P=.89). The 5-year IPTW estimates for recurrence-free survival were 87.8% (95% CI, 81.0%-92.4%) in the moderate hypofractionation group and 88.4% (95% CI 83.2%-92.1%) in the conventional fractionation group. The hazard ratio was 1.02 (95% CI, 0.62-1.67; P=.95). The 5-year IPTW estimates for overall survival were 96.6% (95% CI, 92.0%-98.5%) in the moderate hypofractionation group and 93.4% (95% CI, 88.7%-96.1%) in the conventional fractionation group. The hazard ratio was 0.65 (95% CI, 0.30-1.42; P=.28). Analysis of outcomes in this large observational cohort of patients with triple-negative, node-negative breast cancer treated with whole-breast irradiation revealed no differences by dose fractionation. This adds evidence to support the use of moderate hypofractionation in patients with triple-negative disease.

Evaluating anthracycline\u2009+\u2009taxane versus taxane-based chemotherapy in older women with node-negative triple-negative breast cancer: a SEER-Medicare study

PurposeAdjuvant chemotherapy reduces recurrence in early-stage triple-negative breast cancer (TNBC). However, data are lacking evaluating anthracycline + taxane (ATAX) versus taxane-based (TAX) chemotherapy in older women with node-negative TNBC, as they are often excluded from trials. The purpose of this study was to evaluate the effect of adjuvant ATAX versus TAX on cancer-specific (CSS) and overall survival (OS) in older patients with node-negative TNBC.Patients and methodsUsing the SEER-Medicare database, we selected patients aged ≥ 66 years diagnosed with Stage T1-4N0M0 TNBC between 2010 and 2015 (N = 3348). Kaplan–Meier survival curves and adjusted Cox proportional hazards models were used to estimate 3-year OS and CSS. Multivariant Cox regression analysis was used to identify independent factors associated with use of ATAX compared to TAX.ResultsApproximately half (N = 1679) of patients identified received chemotherapy and of these, 58.6% (N = 984) received TAX, 25.0% (N = 420) received ATAX, and 16.4% (N = 275) received another regimen. Three-year CSS and OS was improved with any adjuvant chemotherapy from 88.9 to 92.2% (p = 0.0018) for CSS and 77.2% to 88.6% for OS (p < 0.0001). In contrast, treatment with ATAX compared to TAX was associated with inferior 3-year CSS and OS. Three-year CSS was 93.7% with TAX compared to 89.8% (p = 0.048) for ATAX and OS was 91.0% for TAX and 86.4% for ATAX (p = 0.032).ConclusionWhile adjuvant chemotherapy was associated with improved clinical outcomes, the administration of ATAX compared to TAX was associated with inferior 3-year OS and CSS in older women with node-negative TNBC. The use of adjuvant ATAX should be considered carefully in this patient population.

EP.TH.930Contemporary trends in the management of micrometastatic axillary disease in the setting of mastectomy – a 5 year single institution experience

Abstract Background Since the ACOSOG Z0011 trial, rates of axillary node clearance (ANC) for micrometastatic axillary disease have declined among women undergoing breast conservation surgery (BCS). However, for women undergoing mastectomy, it remains unclear whether omission of ANC is a safe and feasible option. Aims Identify current practice relating to management of the axilla in women with early stage, clinically node negative breast cancer, found to have micrometastatic disease on SNB, who undergo mastectomy Methods From 2013 to 2017 patients with clinical T1-T2Nmi breast cancer undergoing upfront surgery were identified from a prospective institutional database. Receipt of adjuvant radiotherapy or subsequent ANC were assessed. Patients who received neoadjuvant chemotherapy or BCS were excluded. Results 47 patients undergoing mastectomy for ESBC had micrometastasis identified on SNB. The majority of tumours had invasive ductal histology. 16/27 women underwent completion ANC (34%). Six patients had further nodal disease identified in the ANC specimen. 2 had &amp;gt;5 nodes positive. During the study period 31 patients (65%) received adjuvant radiotherapy. Of the patients who did not undergo ANC, 21 (67.7%) received adjuvant radiotherapy. Conclusion At this institution the majority of patients requiring mastectomy with micrometastatic disease on SNB do not undergo subsequent ANC (&amp;gt;60%). Although this is a small patient cohort, these data indicate the rate of residual axillary disease is low, and are in keeping with trends in the literature, and may help inform management decisions in this patient group.

MRI-Guided APBI Using Brachytherapy PTV Margins is Well Tolerated With Low Ipsilateral Breast Tumor Recurrence Risk

External beam accelerated partial breast irradiation (APBI) utilizes Planning Target Volume (PTV) expansions of 2 to 2.5 cm beyond the surgical cavity to assure treatment of target breast tissue. Decreasing the volume of irradiated breast with external beam accelerated partial breast irradiation (APBI) is a potential way to minimize dose to organs at risk and adverse cosmetic outcomes. Magnetic resonance guided radiation therapy (MRgRT) allows detailed pre-fraction imaging and continuous intrafraction monitoring which allows for external beam APBI treatments using a brachytherapy-style 1 cm surgical bed to PTV margin. We have previously shown that MRgRT APBI results in an average 52% reduction in PTV. In this study we report the outcomes of patients treated with reduced-margin APBI via MRgRT.Patients included women with early stage, node negative breast cancers treated with breast conserving surgery and adjuvant MRgRT APBI from March 2014 to July 2019. PTV was defined as the surgical cavity plus a uniform 1-cm margin of breast tissue (excluding chest wall, pectoral muscles, and 5mm from skin). The PTV received 38.5 Gy in ten fractions over five treatment days. Volumetric MR imaging was acquired prior to each fraction to localize the surgical cavity and a sagittal cine MR imaging during each treatment to monitor intrafraction motion; gating to the surgical bed was used as needed.242 patients were treated with MRgRT APBI with reduced margins. Eighty-one (33.5%) patients had pure DCIS and 161 (66.5%) patients had pT1N0 disease. Seventy-three (90.1%) patients with pure DCIS had hormone sensitive disease and 141 (87.6%) patients with invasive disease had hormone sensitive, her2/neu negative disease. Stratifying by ASTRO APBI Consensus guidelines, 36% of patients were categorized as Cautionary and one patient was Unsuitable solely due to age < 40. At a median follow up of 36 months (range, 14 - 82), two patients (0.8%) had biopsy-proven in-breast tumor recurrence (IBTR), both of whom were successfully salvaged. Per the Aaronson-modified Harris scale, providers reported 100% of patients had good/excellent cosmesis prior to APBI and at last follow-up. Nearly two thirds of patients experienced no acute skin toxicity with the remaining having small regions of grade 1 erythema. There were no observed CTCAEv4.0 grade 3+ toxicities following APBI.APBI with reduced margins using MR-IGRT is safe and has excellent cosmetic outcomes with acceptably low initial rates of IBTR.

A Comparison of Outcomes in Early-Stage Breast Cancer After External Beam Radiotherapy, Endocrine Therapy, Both, or Neither: A Retrospective Cohort Study Across a Large Health System

Several trials have compared endocrine therapy (ET) alone vs. ET and radiotherapy (RT) in low-risk early-stage ER+ breast cancer and have shown that the addition of RT to ET modestly reduces the rate of loco-regional recurrence (LRR) without altering survival. ET alone has thus become a standard strategy in managing these patients. Data evaluating the efficacy of RT alone is scarce. However, the toxicity of ET is not trivial, so as RT courses become ever shorter and safer, a re-evaluation of the strategy of RT alone is warranted. This analysis reports on outcomes of early-stage node-negative breast cancer treated with RT, ET, both, or neither at a multi-hospital health system. We hypothesized that RT alone yields comparable LRR to ET alone in ER+ positive early-stage breast cancer.The shared electronic health record of multiple facilities within a university health system was queried to identify women with pathologic T1-2 N0 breast cancer treated with breast-conserving surgery between 2007 and 2016. Data collection included demographic features, tumor characteristics, treatment type, and evidence of LRR. Analysis was restricted to those patients with ER+ disease. Five-year LRR were compared across groups using the Kaplan-Meier method. A multivariate analysis was performed to identify factors associated with LRR.1340 patients met inclusion criteria. Of these, 84 were treated with RT alone, 155 with ET alone, 1042 with both RT and ET, and 59 received breast conserving surgery only. Demographic and tumor variables are listed below. The 5-year rates of LRR for RT, ET, both, and neither, respectively, were 4.2% (95% CI 1.4-12.7), 5.6% (95% CI 2.6-11.7), 0.6% (95% CI 0.2-1.4), and 31.9% (95% CI 19.8-48.6). While not receiving any adjuvant therapy was associated with significantly higher rate of LRR (P < 0.001), the difference between RT and ET alone was not significant (P = .395). On multivariate analysis, age < 50 (HR 3.3; 95% CI 1.5-7.1), high grade (HR 2.5; 95% CI 1.1-5.8), and observation (HR 9.8; 95% CI 3.2-29.6) were associated with higher LRR, whereas receipt of both RT and ET was associated with lower LRR (HR 0.2; 95% CI 0.1-0.5).RT yielded LRR equivalent to ET in this population, while the combination was superior to either treatment alone. For patients with early-stage ER+ breast cancer, a prospective randomized trial comparing RT to ET and evaluating quality of life (QoL) is needed. In light of new trial data, a five-day course of RT can be considered; this treatment may yield equivalent LRR and better QoL than a five-year course of ET.