Positive Sentinel Lymph Node Research Articles

Assessing the implications of sentinel lymph node removal in cervical cancer: an immunogenetic perspective – a SENTICOL ancillary study

BackgroundCervical cancer’s lymphatic spread primarily begins from the sentinel lymph nodes (SLNs), underlining their pivotal role in disease metastasis. However, these nodes’ immune gene expression profiles and immunoregulation mechanisms have...

Sentinel lymph node pathological ultrastaging: Final outcome of the Sentix prospective international study in patients with early-stage cervical cancer

ObjectiveTo report the outcome of SLN staging in the SENTIX international prospective trial of SLN biopsy in patients with cervical cancer with an intensive ultrastaging protocol and central quality control and to evaluate how the intensity of pathological assessment correlates with metastatic detection rate in SLNs. MethodsEligible were patients with stages T1a1/LVSI+ to T1b2 (<4 cm, ≤2 cm for fertility sparing), common tumor types, no suspicious lymph nodes on imaging, and bilateral SLN detection. SLNs were examined intraoperatively and processed by an intensive protocol for ultrastaging (paraffin blocks sectioned completely in 150-μm intervals/levels). SLNs from each site were submitted for central quality control. ResultsIn the SENTIX SLN study, 647 out of 733 enrolled patients underwent SLN ultrastaging, identifying 12.5% (81/647) with node positive, N1 cases. Intraoperative detection revealed metastases in 56.8% (46/81) of these cases, categorized into macrometastases (83.7%), micrometastases (26.3%), and isolated tumor cells (9.1%). Ultrastaging identified additional metastatic involvement in 43.2% (35/81) of patients, with detailed sectioning revealing metastases (MAC/MIC) at first level in 20 cases (24.7%), at levels 2–4 in 9 cases (11.1%), and at level ≥5 in 6 cases (7.4%). ConclusionSLN ultrastaging detects additional 43% of N1 (MAC/MIC) in patients with negative LNs by imaging and intraoperative pathological assessment. The detection rate of positive SLN correlates with the intensity (number of levels) of ultrastaging. Examination of four levels from paraffin blocks, which detects >90% of patients with N1, is a reasonable compromise for an international standard for ultrastaging.Study registration:NCT02494063 (ClinicalTrials.gov).

Sentinel Lymph Node Biopsy in Cutaneous Melanoma: Results of a Single-Center Analysis

Sentinel lymph node biopsy (SLNB) in cutaneous melanoma is a staging step in cases of unaffected regional lymph nodes. This method is included in routine practice in many medical facilities of the Russian Federation.Aim. To analyze the results of SLNB in cutaneous melanoma performed using gamma scintigraphy technique with the 99mTc-containing technefit radiopharmaceutical agent.Materials and methods. The prospective study included 97 patients (39.2 % (38/97) men and 60.8 % (59/97) women) with primary cutaneous melanoma who received surgical treatment at the Republican Clinical Oncological Dispensary (Ufa) between February of 2021 and January of 2023. Mean patient age was 57.2 ± 13.2 years (95 % confidence interval (CI) 53.8–61.3 years), mean Breslow thickness per biopsy and histological examination after wide tumor resection was 2.89 ± 2.7 mm (95 % CI 2.2–3.76 mm), median follow-up period was 14 months (interquartile range 8–18 months). 99mTc-containing technefit radiopharmaceutical agent was administered intradermally around melanoma/scar. Accumulation of the radiopharmaceutical in the regional lymph nodes was evaluated using single-photon emission computed tomography/computed tomography (SPECT/CT). Intraoperatively the sentinel lymph node (SLN) was identified using a portable gamma probe. Morphological evaluation was performed in accordance with the protocol approved at the Republican Clinical Oncological Dispensary and based on the updated protocol of the European Organisation for Research and Treatment of Cancer (EORTС) (2019).Results. The percentage of successfully mapped SLNs after radiopharmaceutical administration was 93.8 % (91/97). Mean number of visualized SLNs per SPECT/CT data was 1.7 ± 1.1 SLN (95 % CI 1.5–1.9). SLN biopsy was performed in 91.8 % (89/97) patients. Mean number of identified SLNs during SLNB was 1.9 ± 1.2 (95 % CI 1.6–2.3). Histological and immunohistochemical examinations showed SLN metastases in 22.5 % (20/89) patients; in 77.5 % (69/89) patients, no lymph node metastases were found. SLN biopsy allowed to perform disease staging. During follow-up in 3 patients with negative SLNs metastases in the regional lymph nodes were found, as well as in 2 patients with positive SLNs. The frequency of false negative SLNB results was 13 % (3/23), negative post-test probability was 2.8 % (2/69). V600E mutation in the BRAF gene was found in 42.3 % (22/52) patients.Conclusion. SLN biopsy using the technefit radiopharmaceutical showed satisfactory results: SLNs were identified in 93.8 % of cases. Morphological examination showed SLN metastases in 22.5 % (20/89) of patients.

A nomogram to predict the risk of axillary upstaging in patients with Z0011-eligible breast cancer.

e12606 Background: ACOSOG Z0011 trial showed that in early cT1-2N0 breast cancer patients with 1-2 positive lymph nodes in sentinel lymph node biopsy (SLNB) can safely omit axillary lymph node dissection (ALND) without compromising local control and long-term survival. Although it is widely accepted worldwide, controversy and concerns remain that the incidence of non-sentinel lymph node metastasis may lead to pathological lymph node (pN) upstaging and insufficient systemic treatment. This study aims to identify risk factors for having ≥4 metastatic lymph node (pN2-3) in patients who met Z0011 criteria and received SLNB. Methods: This is a retrospective study enrolled 733 cT1-2N0 breast cancer patients with 1-2 positive SLNs treated between 2011-2022 at Sun Yat-sen Memorial Hospital. All patients had received SLNB followed by ALND. Patients included were divided into the training and validation sets at a 7:3 ratio. Differences were compared between pN1(1-3 LN+) and pN2-3(≥4 LN+) in training set using either t test or chi-squared test. Multivariate logistic regression was conducted to identify risk factors for pN upstaging and to form the basis of a predictive nomogram. The validation was processed in the other validation set and nomogram performance was evaluated using the area under ROC curve (AUC). Results: Among the 733 patients enrolled, 127 (17.3%) patients had pN upstaging (pN2-3) after ALND. There was a big difference of pN upstaging between the patients with 1 (47/511, 9.2%) and 2 (80/222, 36%) positive SLNs. 488 patients were allocated to the training set, among which 18.2% had pN upstaging. In univariate analysis, pN were differed by cT stage, axillary ultrasound appearance, histological grade, molecular subtype, Ki67, lymph vascular invasion, pathological tumor size, SLN metastasis type (micrometastasis or macrometastasis), positive SLN numbers and negative SLN numbers. Multivariate logistic analysis resulted six independent risk factors associated to pN upstaging: ultrasound suspicious node (OR=1.93; 95% CI: 1.08-3.47), positive lympho-vascular invasion (OR=2.27; 95% CI: 1.25-4.13), larger tumor size (OR=2.07; 95% CI: 1.15-3.73), SLN macro-metastasis (OR= 9.15; 95% CI: 1.07-78.13), two positive SLNs (OR= 6.59; 95% CI:3.70-11.76) and less negative SLN number (OR=1.54; 95% CI: 1.22-1.89). These factors were used to construct a predictive nomogram, exhibiting excellent performance with AUC values of 0.819 and 0.827 in the training and validation cohorts respectively. Conclusions: The Z0011-eligible patients with two positive SLNs may have a high risk of pN upstaging and need to be cautious to spare ALND. A practical nomogram is helpful to identify patients at high risk of pN upstaging and avoid insufficient systemic treatment.

Is a completion axillary dissection in patients with early breast cancer with a positive sentinel node necessary? An NCDB-based trial emulation of ACOSOG Z0011.

e12592 Background: The ACOSOG Z0011 Study is a practice-changing phase III clinical trial that promotes the de-escalation of axillary surgery in early breast cancer patients, which supports no completion axillary lymph node dissection (ALND) in clinically node negative patients with 1 or 2 positive sentinel lymph nodes (pSLN). Strong evidence for patients with 3 positive SLN was still lacking. We emulated the Z0011 trial using the National Cancer Database (NCDB) to validate the post-trial evidence in the real-world setting followed by a deeper investigation in the subgroups by the number of pSLN. Methods: NCDB PUF 2020 was queried for clinical T1-2 N0 M0 breast cancer patients diagnosed 2010-2017. The inclusion and exclusion criteria were the same as in the Z0011 trial except for the inclusion of 3 positive sentinel lymph nodes. Sentinel lymph node biopsy (SLNB) alone and ALND were defined using Site-Specific Factor 19. The primary endpoint, overall survival (OS), was modeled by the Cox proportional hazard model. The propensity score-based average treatment effect on the treated (ATT) weighting schema was implemented to generate pseudo samples based on this eligible study population and its subgroups as pSLN = 1, 2, and 3, where covariate balance between the two cohorts was achieved for all observed demographic and disease characteristics. Results: 25,774 patients were included in the analysis. 20311 (78.8%) patients were in the SLNB alone group, and 5463 (21.2%) patients were in the ALND group respectively. The utility rate of SLNB increased steadily over the years from 53.7% in 2010 to 91.0% in 2017. The median age was 60, which was older than that in the Z0011 trial (55). The median follow-up time was 6.78 [95% CI: 4.98-8.81] years. By multivariable analysis using the original sample, SLNB alone and the ALND group had similar survival (HR = 0.99 [95% CI: 0.90-1.09]; P = 0.83). By ATT weighting, the SLNB group had significantly improved survival (HR= 0.88 [95% CI: 0.82-0.95]; P = 0.001). The magnitude of HR is close to that in the Z0011 trial (HR= 0.87 [95% CI: 0.62-1.23]), but the statistical significance was mainly driven by a much larger sample size in this study. In the subgroup ATT weighting analysis for pSLN = 1, the SLNB group had significantly better survival compared to the ALND group (HR = 0.85 [95% CI: 0.79-0.93]; P &lt; 0.001). Survival was equivalent for subgroup patients with pSLN = 2 (HR = 1.04 [95% CI: 0.91-1.19]; P = 0.54), while in the subgroup of pSLN = 3 patients, the SLNB group had a significantly worse survival when compared to the ALND group (HR, 1.22 [95% CI, 1.04-1.45]; P = 0.02). Conclusions: This NCDB-based Trial-Emulation study validates the result of the ACOSOG Z0011 clinical trial through a post-trial and real-world setting, where we confirmed that patients with 1 or 2 pSLN are suitable for SLNB alone, but for patients with 3 pSLN, ALND may still maintain a viable option.

Personalizing Locoregional Therapy in Patients With Breast Cancer in 2024: Tailoring Axillary Surgery, Escalating Lymphatic Surgery, and Implementing Evidence-Based Hypofractionated Radiotherapy.

The management of axillary lymph nodes in breast cancer is continually evolving. Recent data now support omitting axillary lymph node dissection (ALND) in most patients with metastases in up to two sentinel lymph nodes (SLNs) during upfront surgery and those with residual isolated tumor cells after neoadjuvant chemotherapy (NACT). In the upfront surgery setting, ALND is still indicated, however, in patients with clinically node-positive breast cancer or more than two positive SLNs and, after NACT, in case of residual micrometastases and macrometastases. Omission of the sentinel lymph node biopsy (SLNB) can be considered in many postmenopausal patients with small luminal breast cancer, particularly when axillary ultrasound is negative. Several randomized controlled trials (RCTs) are currently aiming at eliminating the remaining indications for ALND and also establishing omission of SLNB in a broader patient population. The movement to deescalate axillary staging is in part because of the association between ALND and lymphedema, which is swelling of an extremity because of lymphatic damage and obstructed lymphatic drainage. To reduce the risk of developing this condition, patients undergoing ALND can undergo reverse mapping of the axilla and immediate reconstruction or bypass of the lymphatics from the involved extremity. Decongestion and compression are the foundation of conservative treatment for established lymphedema, while lymphovenous bypass and lymph node transfer are surgical procedures to address the physiologic dysfunction. Radiotherapy is an essential component of breast locoregional therapy: more than three decades of radiation research has optimized treatment according to patient's risk of local recurrence while substantially reducing the number of treatment visits. High-quality RCTs have shown the efficacy and safety of hypofractionation-more than 2Gy radiation dose per treatment (fraction)-significantly reducing the burden of radiotherapy treatment for many patients with breast cancer. In 2024, guidelines recommend no more than 15-16 fractions for whole-breast and nodal radiotherapy, with some recommending five fractions for whole-breast radiotherapy. In addition, simultaneous integrated boost (SIB) has been shown to be noninferior to sequential boost with regards to ipsilateral breast tumor recurrence with similar or reduced long-term side effects, also reducing overall treatment length. Further RCTs are underway investigating other indications for five fractions, including SIB and regional node irradiation, such that, in future, it may be possible for the majority of breast radiotherapy patients to be treated with a 1-week course. This manuscript serves to outline the latest updates on axillary surgical staging, lymphatic surgery, and evidence-based radiotherapy in the treatment of breast cancer.

The MARIANE-trial: Multicenter phase 1b/2 trial testing safety and efficacy of neoadjuvant intradermal ipilimumab and nivolumab in high-risk stage II melanoma.

TPS9615 Background: Adjuvant anti-PD1 (nivolumab or pembrolizumab) has been shown to improve relapse free survival for patients with high-risk stage II melanoma (IIB-C). However, this therapy probably won’t be reimbursed as standard of care in most European countries due to high costs, and the benefit-risk-ratio. For macroscopic stage III melanoma, neoadjuvant ipilimumab (IPI; anti-CTLA4) plus nivolumab (NIVO; anti-PD1) has been shown to induce high pathologic response rates in the resected lymph nodes, long-term event free survival, and this schedule is currently being compared to adjuvant NIVO in a phase 3 study (NCT04949113). This combination schedule, however, is unsuitable for earlier disease stages, due to high costs and clinical toxicity. In preclinical models, a local tumor draining lymph node directed delivery of anti-PD-1 plus anti-CTLA-4 has been demonstrated to outperform systemic administration on induction of T-cell proliferation and tumor control. In patients, local delivery of anti-PD-1 or anti-CTLA-4 has been suggested to be equally effective in tumor control with a reduction of adverse events. These data have formed the rationale for testing intradermal injections at the excision site of the primary tumor with IPI and NIVO prior to the re-excision and sentinel node procedure in high-risk stage II melanoma patients. Methods: This multicenter, dose-escalating phase Ib/II trial, using a Simon’s two-stage design, is the first trial to test feasibility and efficacy of intradermal IPI plus NIVO in high-risk stage II melanoma patients. In total 21 to 80 patients, diagnosed with a stage T3-4 cutaneous melanoma with ≥ 50% chance of positive sentinel node, naïve for re-excision, sentinel node surgery and immunotherapy, will be included in this trial. Patients will receive 2 cycles of intradermal IPI 0.5 mg + NIVO 1 mg at the excision site of the primary melanoma (every 3 weeks; arm A); 6 cycles intradermal IPI 0.5 mg + NIVO 1 mg (every week; arm B); 2 cycles intradermal IPI 10 mg + NIVO 20 mg (every 3 weeks, arm C); or 2 cycles of intravenous nivolumab 240 mg every 3 weeks combined with the most optimal intradermal regimen of IPI + NIVO (based on the results of arm A, B or C) in arm D. In week 6, patients will undergo sentinel node surgery, whereafter only patients with a non-MPR (&gt;10% vital tumor) will be treated with adjuvant anti-PD1 according to current standard of care. We expect the first patient to be enrolled in March 2024and to be accruing for 1-1.5 years. Clinical trial information: NCT06240143 .

A phase 1/2 study of vusolimogene oderparepvec (RP1) in primary melanoma (mel) to reduce the risk of sentinel lymph node (SLN) metastasis.

TPS9614 Background: The majority of the 80,000 newly diagnosed mel patients in the US have localized early-stage disease and undergo wide local excision (WLE) with or without SLN biopsy. The SLN is a critical prognostic marker and pivotal to immune response initiation, and fosters tumor-mediated immune suppression and pre-metastatic niches. Thus, SLN is a key target for local immune intervention. Vusolimogene oderparepvec (RP1), a locally administered oncolytic immunotherapy, provides a unique opportunity for intervention following mel diagnosis, prior to definitive surgical management. Derived from the HSV1 strain RH018A, RP1 exhibits superior killing on human tumor cell lines, designed with deletions in neurovirulence factors (ICP34.5 and ICP47) and immune-stimulating elements (increased US11 expression, GM-CSF and GALV-GP R-) to maximize oncolytic potency and induce cell death. Preclinical and clinical data demonstrate RP1's robust antitumor efficacy in advanced mel. This trial addresses a crucial gap in understanding RP1's impact on SLN dynamics, holding promise for preventing disease recurrence in this high-risk population. We hypothesize that in mel patients with high risk, clinically node negative disease (pT3b-T4b), administration of RP1 will reduce rates of SLN positivity compared to a historic control by favorably reshaping the immune landscape of the primary tumor, SLN and peripheral blood. Methods: This investigator-initiated, single site, open label, non-randomized phase 1/2 pilot study (NCT06216938) will enroll 25 patients with high-risk, clinically node-negative mel (pT3b-T4b). Major eligibility criteria include diagnosis of pT3b, T4a, or T4b non-uveal mel with visible residual tumor or positive initial biopsy margins, ECOG 0 or 1 and adequate organ function on screening labs. Patients will receive 3 doses (1ml/dose) of RP1, locally injected at the primary tumor site before standard WLE and SLN biopsy (SLNB). The first dose on day 1 will be 10e6 pfu/ml, followed by 10e7 pfu/ml for the next two doses on days 15 and 21, administered over 4-5 weeks before WLE and SLNB. Surgery occurs within 35 days of the 1st RP1 injection to avoid delays in definitive treatment. Biopsies and blood samples are obtained pre- and post-treatment. Patients will be followed for up to 3 years. Safety assessments include physical exams, labs, and adverse events (AE) monitoring. The primary endpoint is the rate of SLN positivity in the overall cohort, calculated by comparing the observed rates to the expected number of positive SLNs for that cohort using the Melanoma Institute of Australia's Prediction Tool. Secondary endpoints include safety and tolerability of RP1, RFS and OS. Exploratory correlative assays will compare the immunophenotype in primary tumor and the SLN (IHC) and in peripheral blood (flow cytometry) between baseline and on treatment. Clinical trial information: NCT06216938 .

New Proposal Strategy of Sentinel Lymph Node Navigation Surgery for Endoscopic Curability C-2: A Retrospective Study.

The purpose of this study was to evaluate the outcomes of the sentinel node navigation surgery (SNNS) followed by limited gastrectomy for early gastric cancer (EGC) with Endoscopic Curability C-2 (eCuraC-2). Between 2001 and 2018, 33 patients were included in this study. Following sentinel node (SN) biopsy using indocyanine green combined with an infrared ray laparoscopic system, limited gastrectomy (LG) [wedge resection (WR), or segmental gastrectomy (SG)] was performed without extended lymphadenectomy. SN detection rate was 97% (32/33). The mean number of SNs per case was 7.8. Three patients (9.1%) with lymph node metastasis (LNM) had a positive SN identified by intraoperative pathological examination. When intraoperative pathologic examination showed SN to be LNM negative, 11 patients underwent WR, and seven were subjected to SG. Postoperative pathological examinations showed no false negatives for LNM, and four patients (12%) had residual cancer in their resected stomachs. Overall survival and disease-specific survival five years after SNNS were 87.9% and 100%, respectively. SNNS followed by LG with lymphatic basin resection may be one of the ideal procedures for patients with eCuraC-2 due to the accurate diagnosis of LNM and favorable disease-specific prognosis.

Impact of an Online Risk Calculator for Sentinel Node Positivity on Management of Patients with T1 and T2 Melanomas

BackgroundPredicting which patients with American Joint Committee on Cancer (AJCC) T1–T2 melanomas will have a positive sentinel lymph node (SLN) is challenging. Melanoma Institute Australia (MIA) developed an internationally validated SLN metastatic risk calculator. This study evaluated the nomogram’s impact on T1–T2 melanoma patient management at MIA.MethodsSLN biopsy (SLNB) rates were compared for the pre- and post-nomogram periods of 1 July 2018–30 June 2019 and 1 August 2020–31 July 2021, respectively.ResultsOverall, 850 patients were identified (pre-nomogram, 383; post-nomogram, 467). SLNB was performed in 29.0% of patients in the pre-nomogram group and 34.5% in the post-nomogram group (p = 0.091). The overall positivity rate was 16.2% in the pre-nomogram group and 14.9% in the post-nomogram group (p = 0.223). SLNB was performed less frequently in T1a melanoma patients in the pre-nomogram group (1.1%, n = 2/177) than in the post-nomogram group (8.6%, n = 17/198) [p ≤ 0.001]. This increase was particularly for melanomas with a risk score ≥ 5%, with an SLN positivity rate of 11.8% in the post-nomogram group (p = 0.004) compared with zero. For T1b melanomas with a risk score of > 10%, the SLNB rate was 40.0% (8/20) pre-nomogram and 75.0% (12/16) post-nomogram (p = 0.049).ConclusionsIn this specialized center, the SLN risk calculator appears to influence practice for melanomas previously considered low risk for metastasis, with increased use of SLNB for T1a and higher-risk T1b melanomas. Further evaluation is required across broader practice settings. Melanoma management guidelines could be updated to incorporate the availability of nomograms to better select patients for SLNB than previous criteria.

Nomograms for metastasis of non-sentinel lymph nodes or more than three lymph nodes in patients with one or two positive sentinel lymph nodes.

The purpose of this study was to provide advice for the indication of regional nodal irradiation (RNI) in patients with one to two positive sentinel lymph nodes (SLNs) without axillary lymph node dissection (ALND). We conducted a retrospective study in Shandong Cancer Hospital, Fudan University Shanghai Cancer Center, and West China Hospital. Logistic analysis was performed in order to explore the influencing factors of positive non-SLNs (NSLNs) and >3 positive nodes among patients with one to two SLNs+. Then, nomograms were constructed. Between May 2010 and 2020, among the 2,845 patients with one to two SLNs+ undergoing ALND (1,992 patients in the training set and 853 patients in the validation set), there were 34.3% harbored NSLNs+ and 15.6% harbored >3 positive nodes. Multivariate analysis showed that cN stage, the number of positive/negative SLN, pathological tumor stage, lympho-vascular invasion (LVI), multicenter, and molecular subtypes were significantly associated with NSLN metastasis. Similarly, multivariate analysis also showed that cN stage, the number of positive/negative SLNs, pathological tumor stage, and LVI could be independent predictors of >3 positive nodes. Then, nomograms for NSLN metastasis and >3 positive nodes were constructed using these parameters, respectively. The nomograms will be useful in estimating positive NSLNs and >3 positive nodes, and they might provide advice for the optimization of RNI.

Intraoperative spectroscopic evaluation of sentinel lymph nodes in breast cancer surgery

Background and objectivesSentinel lymph node (SLN) biopsy is a standard procedure for patients with breast cancer and normal axilla on imaging. Positive SLNs on histological examination can lead to a subsequent surgery for axillary lymph node clearance (ALNC). Here we report a non-destructive technique based on autofluorescence (AF) imaging and Raman spectroscopy for intra-operative assessment of SLNs excised in breast cancer surgery.MethodsA microscope integrating AF imaging and Raman spectroscopy modules was built to allow scanning of lymph node biopsy samples. During AF-Raman measurements, AF imaging determined optimal sampling locations for Raman spectroscopy measurements. After optimisation of the AF image analysis and training of classification models based on data from 85 samples, the AF-Raman technique was tested on an independent set of 81 lymph nodes comprising 58 fixed and 23 fresh specimens. The sensitivity and specificity of AF-Raman were calculated using post-operative histology as a standard of reference.ResultsThe independent test set contained 66 negative lymph nodes and 15 positive lymph nodes according to the reference standard, collected from 78 patients. For this set of specimens, the area under the receiver operating characteristic (ROC) curve for the AF-Raman technique was 0.93 [0.83–0.98]. AF-Raman was then operated in a regime that maximised detection specificity, producing a 94% detection accuracy: 80% sensitivity and 97% specificity. The main confounders for SLN metastasis were areas rich in histiocytes clusters, for which only few Raman spectra had been included in the training dataset.DiscussionThis preliminary study indicates that with further development and extension of the training dataset by inclusion of additional Raman spectra of histiocytes clusters and capsule, the AF-Raman may become a promising technique for intra-operative assessment of SLNs. Intra-operative detection of positive biopsies could avoid second surgery for axillary clearance.

Between Pathological Prostate Cancer Lymph Nodes and Sentinel Nodes: Which Information Is the Leader?

On the basis of the concept of sentinel lymph node biopsy (SLNB), SLNs should contain decisive information for clinical outcomes. In localized prostate cancer patients, this study assessed retrospectively clinical outcome after radical laparoscopic prostatectomy associated with SLNB and extensive pelvic lymph node dissection. A total of 231 consecutive patients of intermediate to high risk were analyzed. Recurrence-free survival (RFS) was assessed with Kaplan-Meier curves. Various pathological parameters were analyzed using univariable and multivariable analyses through Cox regression analysis. The study was approved and registered under 2007-R41. The median follow-up was 7.1 years (95% confidence interval, 6.6-7.5). In total, 38/231 (16.5%) patients were pN1. Of these 38 patients, 27 had only SLN involvement (SLNI), 10 patients had both SLN and non-SLNI, and 1 patient had isolated non-SLNI, indicating a false-negative (FN). If the updated Briganti nomogram threshold set at >7% for recommending extensive pelvic lymph node dissection had been applied to these patients, we would have missed 44% (12/27) of patients with SLNI and 50% (5/10) of patients with SLNI and non-SLNI, as well as the FN patient. At the time of final follow-up, 84/231 (36.5%) patients had recurrence. In multivariable analysis, and regarding node status, the most significant prognostic factor was SLN with macrometastases and/or micrometastases, respectively, P = 10-3 and P < 10-3. No more information was obtained with non-SLN status. Probabilities of RFS between negative and positive SLN patients presented a major significant difference (P < 10-15) with a risk of event 8.75 times more frequent if SLN was involved than if it was metastasis-free. SLNB seems to contain decisive information for the clinical outcome of patients with localized intermediate- and high-risk prostate cancer patients. The question raised is thus whether immediate additional postoperative treatment should be offered to patients with metastatic SLN.

Factors Associated With Additional Axillary Disease in Patients With Positive Sentinel Lymph Nodes After Neoadjuvant Chemotherapy for Breast Cancer.

Background: In previous studies, breast cancer patients with positive sentinel lymph node(s) (SLN) after neoadjuvant chemotherapy (NAC) frequently had additional nonSLN involvement. Per guidelines, residual SLN disease warrants completion axillary lymph node dissection (cALND), which has increased morbidity. Given recent improvements in NAC, we hypothesized that nonSLN positivity may be lower than previously reported for certain subgroups.Methods: We retrospectively reviewed breast cancer patients who received NAC and had positive lymph nodes on SLN biopsy or targeted axillary dissection and underwent cALND at one institution in 1/2018-8/2023. Associations between nonSLN positivity and clinicopathologic factors were assessed with Fisher's exact test and multivariable logistic regression.Results: There were 122 female patients. Median age was 48years. Initially, 15 patients (12.3%) were cN0 and 107 patients (87.7%) were cN1. Largest SLN deposit was macrometastasis in 96 patients (78.7%), micrometastasis in 23 patients (18.9%), and isolated tumor cells in 3 patients (2.5%). Overall, 53 patients (43.4%) had nonSLN involvement. NonSLN positivity was higher in patients with cN1, ER+ HER2-, ypT2-3, SLN macrometastasis, and multiple positive SLN. On multivariable analysis, cN1 and ER+ HER2- remained associated with nonSLN positivity.Discussion: Among patients with positive SLN after NAC, clinically node positive and ER+ HER2- patients were more likely to have nonSLN involvement. Our findings support guidelines to consider omitting cALND in clinically node negative patients. With improving NAC, optimal axillary sampling, and radiation, omitting cALND may be safe in some clinically node positive triple negative or HER2+ patients with low volume residual disease, but further research is needed.

Abstract PO3-02-08: Risk factors and a new predictive nomogram for predicting the Non-sentinel Lymph Node Metastasis in 708 early-stage Breast Cancer Patients with Positive Sentinel Nodes in China

Abstract Objective: The management of positive sentinel lymph node biopsies (SLNB) in patients with early-stage breast cancer remains a matter of controversy. Some studies have shown that not all breast cancer patients with positive sentinel lymph nodes (SLNs) benefit from further axillary lymph node dissection (ALND). Our study aims to analyse the risk factors and construct a new nomogram to predict non-sentinel lymph node (NSLN) metastasis in Chinese early-stage breast cancer patients with positive sentinel lymph nodes. Methods: The clinical data of 708 patients with early-stage breast cancer who attended The Fourth Hospital of Hebei Medical University for surgical treatment from January 2016 to December 2021 was retrospectively analyzed. All of them were female breast cancer patients with positive sentinel lymph nodes and underwent ALND. The patients were divided into modeling group and validation group according to the time of treatment. The patients in the modeling group were divided into a positive NSLN group and a negative NSLN group. The characteristics: age, maximum tumor diameter, the number of positive SLNs, proportion of positive SLNs, vessel carcinoma embolus, nerve invasion, status of ER, PR, HER-2 and Ki-67 were included in the analysis. And the independent risk factors of NSLN metastasis were screened by univariate (chi-square test) and multivariate (logistic regression) analysis. A nomogram model was established according to the screened independent risk factors, and the model was externally validated by the validation group. The ROC curve was plotted to calculate the area under the curve (AUC) and evaluate the predictive power of the nomogram model. A calibration curve and decision curve analysis (DCA) were used to evaluate the performance of the model. Results: Among the 708 patients, (modeling group n=410, validation group n=298), the average age, average number of positive SLNs, and NSLN positive rate were 50.9±11.1, 1.55±0.87 and 25.71%. The univariate analysis revealed statistically significant differences in the number of positive SLNs (P&amp;lt; 0.001), the proportion of positive SLNs (P &amp;lt; 0.001), vessel carcinoma embolus (P=0.001), nerve invasion (P=0.012), and ER status (P=0.029) in the NSLN-positive group compared with the negative group. The multifactorial logistic regression analysis revealed that the number of positive SLN (P=0.002; OR: 1.700; 95% CI: 1.219-2.370), the proportion of positive SLN (P=0.048; OR: 3.214; 95% CI: 1.001-10.490), vessel carcinoma embolus (P=0.010; OR: 2.076; 95% CI: 1.194-3.612), nerve invasion (P=0.024; OR: 2.119; 95% CI: 1.221-3.678), and ER status (P=0.045; OR: 2.978; 95% CI: 1.022-8.675) were independent risk factors for NSLN positivity. Furthermore, the nomogram was built using these 5 factors and validated on 298 patients in the validation group. The AUC was 0.728 (P&amp;lt; 0.001; 95%CI: 0.673-0.784) in the modeling group and 0.810 (P&amp;lt;0.001; 95%CI: 0.735-0.886) in the validation group. The calibration curves of the modeling and validation groups were close to the ideal curve, and DCA also showed that the model could be applied in clinical practice. Conclusion: For early-stage breast cancer with positive SLNs, these factors as the positive number of SLNs &amp;gt; 2, the ratio of positive SLNs &amp;gt; 50%, vessel carcinoma embolus, nerve invasion and ER-positive could predict NSLN metastasis well. The proposed nomogram appears to accurately estimate the likelihood of positive NSLNs and may greatly help the surgeon to decide intraoperatively whether to perform further ALND and avoid non-essential ALND as well as postoperative complications. Citation Format: Zhenchuan Song, Xueyi Zhao, Liu Yang. Risk factors and a new predictive nomogram for predicting the Non-sentinel Lymph Node Metastasis in 708 early-stage Breast Cancer Patients with Positive Sentinel Nodes in China [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 PO3-02-08.

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 PO5-20-01: SENTINOT2- Use of superparamagnetic iron oxide tracer to avoid unnecessary sentinel lymph node biopsies

Abstract Background/Purpose: The use of superparamagnetic nanoparticles of iron oxide tracers (Magtrace) and electromagnetometers (SentiMag) for the detection of sentinel lymph nodes (SLN) during breast cancer surgery has been demonstrated to be noninferior to traditional radioisotope (RI) and blue dye detection, with additional safety benefits. Previous work has shown that transcutaneous detection of SLN with Magtrace/Sentimag is possible for over 30 days. Because of the safety, efficacy, and long detection window of Magtrace, we aim to investigate the use of Magtrace to prevent unnecessary SLN biopsies (SLNB) in breast cancer surgery. SLNB are commonly performed during breast conserving surgeries (BCS) or mastectomy for patients with a preoperative diagnosis of ductal carcinoma in-situ (DCIS). Because metastasis is not expected in patients diagnosed with DCIS, SLNB may be unnecessary and potentially harmful. However, in 15-25% of cases, unexpected invasive carcinoma is found during the post-surgical histopathological analysis of the resected breast tissue. For these cases, if SLNB are forgone during the initial surgery, SLNB during a second (delayed) procedure is the usual standard of care to evaluate SLN for metastasis. However, potential changes to lymphatic drainage following the initial resection may affect tracer localization to SLN. Consequently, we aim to compare SLN detection rates during delayed SLNB with Magtrace administered prior to initial BCS or mastectomy and subsequent RI tracer administered prior to delayed SLNB. Methods: SENTINOT2 is an ongoing international trial with BCM as the sole US site. For eligible patients with a preoperative diagnosis of DCIS, Magtrace will be administered prior to BCS or mastectomy. If invasive carcinoma is found from the post-surgical histopathological analysis, patients will receive delayed SLNB within 4 weeks of their initial surgery. Prior to delayed SLNB, patients will be randomized into two groups differing in the order of modality used for SLN detection (Magtrace or RI). Subjects with the following conditions will be excluded from the study: hypersensitivity to Magtrace, iron overload disease, pregnancy, and lactation. The total expected accrual for this study is 538 subjects globally and 50 subjects at BCM. Results: Currently, 19 patients have been enrolled in SENTINOT2. The subject population is 11% Asian, 26% Black/African American, and 47% Caucasian with non-Hispanic ethnicity. 5% of subjects identified as Hispanic Caucasian and 11% of subjects declined to report their race or ethnicity. 79% of patients had mastectomies, while 21% had BCS. After post-surgical histopathological analysis, 21% (4/19) patients were determined to have invasive carcinoma and received delayed SLNB. 50% (2/4) of these patients were randomized to have Magtrace as their first SLN detection modality (Mag-RI) while the other 50% (2/4) had RI as their first SLN detection modality (RI-Mag). Table 1 shows comparable SLN detection rates between Magtrace and RI for patients who received delayed SLNB. Only 1/4 patients showed SLN metastasis. For this patient, the positive SLN was successfully detected by both modalities. Conclusion: Magtrace has shown potential in delayed SLN detection and the use of Magtrace has prevented 79% (15/19) of enrolled patients from receiving unnecessary SLNB. Table 1. Number of Lymph Nodes (LN) Detected by Magtrace/Radioisotope, Biopsied and Positive for Metastasis Citation Format: Mary Bajomo, Ivan Marin, Jessica Montalvan, Margarita Riojas-Barrett, Logan Healy, Elizabeth Bonefas, Stacey Carter, Alastair Thompson. SENTINOT2- Use of superparamagnetic iron oxide tracer to avoid unnecessary sentinel lymph node biopsies [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 PO5-20-01.

Abstract PO4-19-07: Tailored Axillary Surgery (TAS) in Patients with Clinically Node-Positive Breast Cancer in the Upfront Surgery Setting: A Prospective, Single-Arm, Multicenter Trial

Abstract A brief background discussion: Axillary lymph node dissection (ALND), which can induce lymphedema, has been omitted in clinically node-negative(cN0) patients with positive sentinel lymph nodes (SLNs) if they meet the eligibility criteria of ACOSOG Z0011. Furthermore, the omission of ALND has been attempted through targeted axillary dissection (TAD) in patients whose clinically node-positive(cN+) status converts to ycN0 after neoadjuvant chemotherapy. However, ALND remains the standard of care in patients with cN+ who undergo upfront surgery. Trial design: This is a prospective, single-arm, multicenter phase II feasibility trial with the participation of 41 hospitals belonging to the breast cancer study group of Japan Clinical Oncology Group (JCOG). Tailored axillary surgery (TAS) removes labeled lymph node (LN) with clip, wire, or tattoo, palpable LNs, and SLNs. ALND is performed after TAS. These LNs removed by ALND other than TAS are defined as non-TAS LNs. Eligibility criteria: The eligibility criteria are as follows: 1) histologically-proven invasive breast cancer, 2) upfront surgery is planned, 3) pathologically diagnosed metastatic LN (cytology or core needle biopsy), 4) 1-3 LN metastases in level I by imaging, 5) cT1-3, and 6) females aged ≥18 and ≤74 years on the enrollment date. Specific aims: This trial aims to establish a surgical method of tailored axillary surgery (TAS) among patients with cN+ who undergo upfront surgery and to determine the appropriate criteria for the next phase III TAS trial, which omits ALND by TAS safely. The primary endpoint is the non-TAS LNs positive rate. Clinicopathological factors (the number of suspected metastases by imaging, the number of metastases in LNs resected by TAS, tumor size, and invasive ductal/lobular carcinoma) are analyzed to predict the non-TAS LN metastasis rate (e.g., &amp;lt; 10%). The secondary endpoints are the TAS LNs identification rate, marked LN resection rate, arm edema incidence rate, and QOL (FACT-B, QuickDASH). Statistical methods: In this trial, among the combinations of factors involved in treatment selection, the objective is to narrow down the combinations that will result in a non-TAS metastasis-positive rate of less than 10% when TAS is performed. For a single combination, 167 cases need to be considered to reject a non-TAS metastasis-positive rate of 10% or more (5% one-sided alpha error, 70% power, and 5% expected value). However, performing these studies for all combinations lacks feasibility. Therefore, we decided to improve the estimation accuracy by using a regression model with the non-TAS metastasis-positive rate as the outcome variable and the factors involved in treatment selection as explanatory variables and to search for combinations of factors with a non-TAS metastasis-positive rate less than 10%. Based on the rule of thumb that a sample size of at least ten times the number of factors is required when using regression methods, a regression model is used when 60 cases are accumulated. The combinations with a 90% confidence upper limit of less than 10% of non-TAS metastasis positivity as the predictive value of the regression model will be selected as candidate combinations that fulfill the conditions. If the accuracy of the predictive value is considered insufficient, 60 cases will be added sequentially up to a maximum of 300 cases. Present accrual and target accrual: The patient recruitment was started in April 2023. Up to 300 patients will be enrolled over a 2-year recruitment period. Twenty-one patients were already enrolled until July 2023. Citation Format: Kaori Terata, Yasuaki Sagara, Tadahiko Shien, Takehiko Sakai, Shin Takayama, Dai Kitagawa, Tsuguo Iwatani, Takahiro Tsukioki, Mami Ogita, Naoko Sanuki, Masayuki Yoshida, Hitoshi Tsuda, Seiichiro Yamamoto, Hiroji Iwata. Tailored Axillary Surgery (TAS) in Patients with Clinically Node-Positive Breast Cancer in the Upfront Surgery Setting: A Prospective, Single-Arm, Multicenter 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 PO4-19-07.

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 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.