Omitting Axillary Dissection in Breast Cancer with Sentinel-Node Metastases.

BACKGROUND: Trials evaluating the omission of completion axillary-lymph-node dissection in patients with clinically node-negative breast cancer and sentinel-lymph-node metastases have been compromised by limited statistical power, uncertain nodal radiotherapy target volumes, and a scarcity of data on relevant clinical subgroups. METHODS: We conducted a noninferiority trial in which patients with clinically node-negative primary T1 to T3 breast cancer (tumor size, T1, ≤20 mm; T2, 21 to 50 mm; and T3, >50 mm in the largest dimension) with one or two sentinel-node macrometastases (metastasis size, >2 mm in the largest dimension) were randomly assigned in a 1:1 ratio to completion axillary-lymph-node dissection or its omission (sentinel-node biopsy only). Adjuvant treatment and radiation therapy were used in accordance with national guidelines. The primary end point was overall survival. We report here the per-protocol and modified intention-to-treat analyses of the prespecified secondary end point of recurrence-free survival. To show noninferiority of sentinel-node biopsy only, the upper boundary of the confidence interval for the hazard ratio for recurrence or death had to be below 1.44. RESULTS: Between January 2015 and December 2021, a total of 2766 patients were enrolled across five countries. The per-protocol population included 2540 patients, of whom 1335 were assigned to undergo sentinel-node biopsy only and 1205 to undergo completion axillary-lymph-node dissection (dissection group). Radiation therapy including nodal target volumes was administered to 1192 of 1326 patients (89.9%) in the sentinel-node biopsy-only group and to 1058 of 1197 (88.4%) in the dissection group. The median follow-up was 46.8 months (range, 1.5 to 94.5). Overall, 191 patients had recurrence or died. The estimated 5-year recurrence-free survival was 89.7% (95% confidence interval [CI], 87.5 to 91.9) in the sentinel-node biopsy-only group and 88.7% (95% CI, 86.3 to 91.1) in the dissection group, with a country-adjusted hazard ratio for recurrence or death of 0.89 (95% CI, 0.66 to 1.19), which was significantly (P<0.001) below the prespecified noninferiority margin. CONCLUSIONS: The omission of completion axillary-lymph-node dissection was noninferior to the more extensive surgery in patients with clinically node-negative breast cancer who had sentinel-node macrometastases, most of whom received nodal radiation therapy. (Funded by the Swedish Research Council and others; SENOMAC ClinicalTrials.gov number, NCT02240472.).

Completion axillary lymph node dissection for the identification of pN2-3 status as an indication for adjuvant CDK4/6 inhibitor treatment: a post-hoc analysis of the randomised, phase 3 SENOMAC trial.

BACKGROUND: In luminal breast cancer, adjuvant CDK4/6 inhibitors (eg, abemaciclib) improve invasive disease-free survival. In patients with T1-2, grade 1-2 tumours, and one or two sentinel lymph node metastases, completion axillary lymph node dissection (cALND) is the only prognostic tool available that can reveal four or more nodal metastases (pN2-3), which is the only indication for adjuvant abemaciclib in this setting. However, this technique can lead to substantial arm morbidity in patients. We aimed to pragmatically describe the potential benefit and harm of this strategy on the individual patient level in patients from the ongoing SENOMAC trial. METHODS: In the randomised, phase 3, SENOMAC trial, patients aged 18 years or older, of any performance status, with clinically node-negative T1-T3 breast cancer and one or two sentinel node macrometastases from 67 sites in five European countries (Denmark, Germany, Greece, Italy, and Sweden) were randomly assigned (1:1), via permutated block randomisation (random block size of 2 and 4) stratified by country, to either cALND or its omission (ie, they had a sentinel lymph node biopsy only). The primary outcome is overall survival, which is yet to be reported. In this post-hoc analysis, patients from the SENOMAC per-protocol population, with luminal oestrogen-receptor positive, HER2-negative, T1-2, histological grade 1-2 breast cancer, with tumour size of 5 cm or smaller were selected to match the characteristics of cohort 1 of the monarchE trial who would only have an indication for adjuvant abemaciclib if found to have 4 or more nodal metastases. The primary study objective was to determine the number of patients who developed patient-reported severe or very severe impairment of physical arm function after cALND (as measured by the Lymphedema Functioning, Disability, and Health [Lymph-ICF] Questionnaire) 1 year after surgery to avoid one invasive disease-free survival event at 5 years with 2 years of adjuvant abemaciclib, using invasive disease-free survival event data from cohort 1 of the monarchE trial. The SENOMAC trial is registered with ClincialTrials.gov, NCT02240472, and is closed to accrual and ongoing. FINDINGS: Between Jan 31, 2015, and Dec 31, 2021, 2766 patients were enrolled in SENOMAC and randomly assigned to cALND (n=1384) or sentinel node biopsy only (n=1382), of whom 2540 were included in the per-protocol population. 1705 (67%) of 2540 patients met this post-hoc study's eligibility criteria, of whom 802 (47%) had a cALND and 903 (53%) had a sentinel lymph node biopsy only. Median age at randomisation was 62 years (IQR 52-71), 1699 (>99%) of 1705 patients were female, and six (<1%) were male. Among 1342 patients who responded to questionnaires, after a median follow-up of 45·2 months (IQR 25·6-59·8; data cutoff Nov 17, 2023), patient-reported severe or very severe impairment of physical arm function was reported in 84 (13%) of 634 patients who had cALND versus 30 (4%) of 708 who had sentinel lymph node biopsy only (χ2 test p<0·0001). To avoid one invasive disease-free survival event at 5 years with adjuvant abemaciclib, cALND would need to be performed in 104 patients, and would result in nine patients having severe or very severe impairment of physical arm function 1 year after surgery. INTERPRETATION: As a method to potentially identify an indication for abemaciclib, and subsequently avoid invasive disease-free survival events at 5 years with 2 years of adjuvant abemaciclib, cALND carries a substantial risk of severe or very severe arm morbidity and so cALND should be discouraged for this purpose. FUNDING: Swedish Research Council, the Swedish Cancer Society, the Nordic Cancer Union, and the Swedish Breast Cancer Association.

Micrometastases in axillary lymph nodes in breast cancer, post-neoadjuvant systemic therapy.

INTRODUCTION: The significance of minimal residual axillary disease, specifically micrometastases, following neoadjuvant systemic therapy (NST) remains largely unexplored. Our study aimed to elucidate the prognostic implications of micrometastases in axillary and sentinel lymph nodes following NST. METHODS: This retrospective study analyzed primary breast cancer patients who underwent surgery after NST from September 2006 through February 2018. All patients received axillary lymph node dissection (ALND), either with or without sentinel lymph node biopsy. Recurrence-free survival (RFS)-associated variables were identified using a multivariate Cox proportional hazard model. RESULTS: Of the 978 patients examined, 438 (44.8%) exhibited no pathologic lymph node involvement (ypN0) after NST, while 89 (9.1%) had micrometastases (ypN1mi) and 451 (46.7%) had macrometastases (ypN+). Notably, 51.1% of the patients with sentinel lymph node micrometastases (SLNmi) had additional metastases, nearly triple that of SLN-negative patients (P < 0.001), and 29.8% of SLNmi patients were upstaged with the ALND. Although ypN1mi was not associated with RFS in patients post-NST (HR, 1.02; 95% CI, 0.42-2.49; P = 0.958), SLNmi patients experienced significantly worse RFS compared to SLN-negative patients (hazard ratio [HR], 2.23; 95% confidence intervals [CI], 1.12-4.46; P = 0.023). Additional metastases in SLNmi were more prevalent in patients with larger residual breast disease greater than 20 mm, HR-positive/HER2-negative subtype, and low Ki-67 LI (< 14%). CONCLUSIONS: SLNmi is a negative prognostic factor significantly associated with additional non-SLN metastases, while ypN1mi does not influence the prognosis compared to ypN0. Hence, additional ALND may be warranted to confirm axillary nodal status in patients with SLNmi.

Should patients with hormone receptor-positive, HER2-negative breast cancer and one or two positive sentinel nodes undergo axillary dissection to determine candidacy for adjuvant abemaciclib?

BACKGROUND: The monarchE trial demonstrated improved outcomes with the use of adjuvant abemaciclib in patients with high-risk hormone receptor-positive, HER2-negative (HR+/HER2-) breast cancer defined as ≥4 positive lymph nodes (+LNs) or one to three +LNs with one or more additional high-risk features (HRFs). The proportion of patients with one or two positive sentinel lymph nodes (+SLNs) without HRFs who had ≥4 +LNs at the time of completion axillary lymph node dissection (cALND), and who therefore qualified for receipt of abemaciclib, was investigated. METHODS: Females with pathologically node-positive nonmetastatic HR+/HER2- breast cancer stratified by the number of +SLNs and +LNs and the presence of one or more HRFs were identified from the National Cancer Database (2018-2019). The proportion of patients meeting the criteria for abemaciclib both before and after ALND was assessed. RESULTS: Of the 22,048 patients identified, 1578 patients underwent upfront surgery, had one or two +SLNs without HRFs, and went on to cALND. Only 213 (13%) of these patients had ≥4 +LNs; thus, cALND performed solely to determine abemaciclib candidacy would have constituted surgical overtreatment in 1365 patients (87%). When stratified by the number of +SLNs, only 10% of those with one +SLN and 24% of those with two +SLNs had ≥4 +LNs after cALND, which meets the criteria for abemaciclib. CONCLUSIONS: Patients with one +SLN without HRFs are unlikely to have ≥4 +LNs and should not be subjected to the morbidity of ALND in order to inform candidacy for abemaciclib. An individualized multidisciplinary discussion should be undertaken about the risk:benefit ratio of ALND and abemaciclib for those with two +SLNs.

An ultrasound-based nomogram for predicting axillary node pathologic complete response after neoadjuvant chemotherapy in breast cancer: Modeling and external validation.

INTRODUCTION: The staging and treatment of axillary nodes in breast cancer have become a focus of research. For breast cancer patients with fine-needle aspiration-or core needle biopsy-confirmed positive nodes, axillary lymph node dissection (ALND) after neoadjuvant chemotherapy (NAC) is still a standard treatment. However, some patients achieve an axillary pathologic complete response (pCR) after NAC. In this study, the authors sought to construct a model to predict axillary pCR in patients with positive axillary lymph nodes (cN+) breast cancer. METHODS: Data from patients with pathologically proven cN+ breast cancer treated with NAC followed by ALND between January 2010 and April 2019 at the Peking University Cancer Hospital were reviewed. Axillary lymph node status was assessed using ultrasonography before and after NAC. The patient cohort was assigned to the construction and internal validation cohorts according to admission time. A nomogram was constructed based on the significant factors associated with axillary pCR. The predictive performance of the model was externally validated using data from Peking University First Hospital. RESULTS: This study included 953 and 267 patients from Peking University Cancer Hospital and Peking University First Hospital, respectively. In the construction cohort, 39.7% (238 of 600) of patients achieved axillary pCR after NAC. The result of multivariate logistic regression analysis showed that tumor grade, clinical nodal response, NAC regimen, tumor pCR, lymphovascular invasion, and tumor biologic subtype were significant independent predictors of ypN0 (p < 0.05). The areas under the receiver operating characteristic curves for the construction, validation, and independent testing cohorts were 0.87 (95% confidence interval [CI], 0.84-0.90), 0.83 (95% CI, 0.79-0.87), and 0.84 (0.79-0.89), respectively. CONCLUSIONS: A nomogram was constructed to predict the pCR of axillary lymph nodes after NAC for breast cancer. Validation of both the internal and external cohorts achieved good predictive performance, indicating that the model has preliminary clinical application prospects.

Rethinking surgical revisions: impact of the MonarchE trial on axillary dissection in hormone-positive HER2-negative early breast cancer patients potentially eligible for abemaciclib.

INTRODUCTION: The MonarchE trial explored the use of abemaciclib, a CDK4/6 inhibitor, as an adjuvant treatment in high-risk early-stage luminal-like breast cancer. The study's inclusion criteria, especially the N2 status, may require revisiting surgical interventions, including invasive axillary lymph node dissection (ALND)-a procedure that current guidelines generally do not recommend. METHODS: We conducted a single-centre, retrospective, observational cohort study on non-metastatic breast cancer patients managed from 2002 to 2011, at the Institut Curie. Data collection involved clinical and histological characteristics plus treatment follow-up. RESULTS: Out of 8715 treated patients, 721 met the inclusion criteria. Overall, 12% (87) were classified as N2 ( ≥ 4 positive lymph nodes), thus eligible for abemaciclib per "node criterion." Tumour size, positive sentinel lymph nodes, and lobular histology showed a significant correlation with N2 status. Approximately 1000 ALNDs would be required to identify 120 N2 cases and prevent four recurrences. CONCLUSION: The MonarchE trial may significantly affect surgical practices due to the need for invasive procedures to identify high-risk patients for adjuvant abemaciclib treatment. The prospect of unnecessary morbidity demands less invasive N2 status determination methods. Surgical decisions must consider patient health and potential treatment benefits.

A non-invasive artificial intelligence model for identifying axillary pathological complete response to neoadjuvant chemotherapy in breast cancer: a secondary analysis to multicenter clinical trial.

BACKGROUND: This study aims to develop a stacking model for accurately predicting axillary lymph node (ALN) response to neoadjuvant chemotherapy (NAC) using longitudinal MRI in breast cancer. METHODS: We included patients with node-positive breast cancer who received NAC following surgery from January 2012 to June 2022. We collected MRIs before and after NAC, and extracted radiomics features from the tumour, peritumour, and ALN regions. The Mann-Whitney U test, least absolute shrinkage and selection operator, and Boruta algorithm were used to select features. We utilised machine learning techniques to develop three single-modality models and a stacking model for predicting ALN response to NAC. RESULTS: This study consisted of a training cohort (n = 277), three external validation cohorts (n = 313, 164, and 318), and a prospective cohort (n = 81). Among the 1153 patients, 60.62% achieved ypN0. The stacking model achieved excellent AUCs of 0.926, 0.874, and 0.862 in the training, external validation, and prospective cohort, respectively. It also showed lower false-negative rates (FNRs) compared to radiologists, with rates of 14.40%, 20.85%, and 18.18% (radiologists: 40.80%, 50.49%, and 63.64%) in three cohorts. Additionally, there was a significant difference in disease-free survival between high-risk and low-risk groups (p < 0.05). CONCLUSIONS: The stacking model can accurately predict ALN status after NAC in breast cancer, showing a lower false-negative rate than radiologists. TRIAL REGISTRATION NUMBER: The clinical trial numbers were NCT03154749 and NCT04858529.

Radiotherapy to regional nodes in early breast cancer: an individual patient data meta-analysis of 14 324 women in 16 trials.

BACKGROUND: Radiotherapy has become much better targeted since the 1980s, improving both safety and efficacy. In breast cancer, radiotherapy to regional lymph nodes aims to reduce risks of recurrence and death. Its effects have been studied in randomised trials, some before the 1980s and some after. We aimed to assess the effects of regional node radiotherapy in these two eras. METHODS: In this meta-analysis of individual patient data, we sought data from all randomised trials of regional lymph node radiotherapy versus no regional lymph node radiotherapy in women with early breast cancer (including one study that irradiated lymph nodes only if the cancer was right-sided). Trials were identified through the EBCTCG's regular systematic searches of databases including MEDLINE, Embase, the Cochrane Library, and meeting abstracts. Trials were eligible if they began before Jan 1, 2009. The only systematic difference between treatment groups was in regional node radiotherapy (to the internal mammary chain, supraclavicular fossa, or axilla, or any combinations of these). Primary outcomes were recurrence at any site, breast cancer mortality, non-breast-cancer mortality, and all-cause mortality. Data were supplied by trialists and standardised into a format suitable for analysis. A summary of the formatted data was returned to trialists for verification. Log-rank analyses yielded first-event rate ratios (RRs) and confidence intervals. FINDINGS: We found 17 eligible trials, 16 of which had available data (for 14 324 participants), and one of which (henceforth excluded), had unavailable data (for 165 participants). In the eight newer trials (12 167 patients), which started during 1989-2008, regional node radiotherapy significantly reduced recurrence (rate ratio 0·88, 95% CI 0·81-0·95; p=0·0008). The main effect was on distant recurrence as few regional node recurrences were reported. Radiotherapy significantly reduced breast cancer mortality (RR 0·87, 95% CI 0·80-0·94; p=0·0010), with no significant effect on non-breast-cancer mortality (0·97, 0·84-1·11; p=0·63), leading to significantly reduced all-cause mortality (0·90, 0·84-0·96; p=0·0022). In an illustrative calculation, estimated absolute reductions in 15-year breast cancer mortality were 1·6% for women with no positive axillary nodes, 2·7% for those with one to three positive axillary nodes, and 4·5% for those with four or more positive axillary nodes. In the eight older trials (2157 patients), which started during 1961-78, regional node radiotherapy had little effect on breast cancer mortality (RR 1·04, 95% CI 0·91-1·20; p=0·55), but significantly increased non-breast-cancer mortality (1·42, 1·18-1·71; p=0·00023), with risk mainly after year 20, and all-cause mortality (1·17, 1·04-1·31; p=0·0067). INTERPRETATION: Regional node radiotherapy significantly reduced breast cancer mortality and all-cause mortality in trials done after the 1980s, but not in older trials. These contrasting findings could reflect radiotherapy improvements since the 1980s. FUNDING: Cancer Research UK, Medical Research Council.

Current axillary management of patients with early breast cancer and low-volume nodal disease undergoing primary surgery: results of a United Kingdom national practice survey.

PURPOSE: UK NICE guidelines recommend axillary node clearance (ANC) should be performed in all patients with biopsy-proven node-positive breast cancer having primary surgery. There is, however, increasing evidence such extensive surgery may not always be necessary. Targeted axillary dissection (TAD) may be an effective alternative in patients with low-volume nodal disease who are clinically node negative (cN0) but have abnormal nodes detected radiologically. This survey aimed to explore current management of this group to inform feasibility of a future trial. METHODS: An online survey was developed to explore current UK management of patients with low-volume axillary disease and attitudes to a future trial. The survey was distributed via breast surgery professional associations and social media from September to November 2022. One survey was completed per unit and simple descriptive statistics used to summarise the results. RESULTS: 51 UK breast units completed the survey of whom 78.5% (n = 40) reported performing ANC for all patients with biopsy-proven axillary nodal disease having primary surgery. Only 15.7% of units currently performed TAD either routinely (n = 6, 11.8%) or selectively (n = 2, 3.9%). There was significant uncertainty (83.7%, n = 36/43) about the optimal surgical management of these patients. Two-thirds (n = 27/42) of units felt an RCT comparing TAD and ANC would be feasible. CONCLUSIONS: ANC remains standard of care for patients with low-volume node-positive breast cancer having primary surgery in the UK, but considerable uncertainty exists regarding optimal management of this group. This survey suggests an RCT comparing the outcomes of TAD and ANC may be feasible.

Superparamagnetic iron oxide (SPIO) for axillary mapping in patients with ductal carcinoma in situ undergoing mastectomy: single-institution experience.

PURPOSE: Unnecessary axillary surgery can potentially be avoided in patients with DCIS undergoing mastectomy. Current guidelines recommend upfront sentinel lymph node biopsy during the index operation due to the potential of upstaging to invasive cancer. This study reviews a single institution's experience with de-escalating axillary surgery using superparamagnetic iron oxide dye for axillary mapping in patients undergoing mastectomy for DCIS. METHODS: This is a retrospective single-institution cross-sectional study. All medical records of patients who underwent mastectomy for a diagnosis of DCIS from August 2021 to January 2023 were reviewed and patients who had SPIO injected at the time of the index mastectomy were included in the study. Descriptive statistics of demographics, clinical information, pathology results, and interval sentinel lymph node biopsy were performed. RESULTS: A total of 41 participants underwent 45 mastectomies for DCIS. The median age of the participants was 58 years (IQR = 17; range 25 to 76 years), and the majority of participants were female (97.8%). The most common indication for mastectomy was diffuse extent of disease (31.7%). On final pathology, 75.6% (34/45) of mastectomy specimens had DCIS without any type of invasion and 15.6% (7/45) had invasive cancer. Of the 7 cases with upgrade to invasive disease, 2 (28.6%) of them underwent interval sentinel lymph node biopsy. All sentinel lymph nodes biopsied were negative for cancer. CONCLUSION: The use of superparamagnetic iron oxide dye can prevent unnecessary axillary surgery in patients with DCIS undergoing mastectomy.

A systematic review and meta-analysis of diagnostic performance of fluorescein-guided sentinel lymph node biopsy in early breast cancer.

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 or alternative to isotope like Indocyanine green (ICG). Both are very resource-intensive; which has prompted development of low-cost technique of Fluorescein Sodium (FS)-guided SLNB. This systematic review and meta-analysis evaluate the diagnostic performance of FS-guided SLNB in early breast cancer. OBJECTIVES: The objective was to evaluate the diagnostic performance of FS for sentinel lymph node biopsy. METHODS: Eligibility criteria: Studies where SLNB was performed using FS. 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 Sentinel Lymph Node Identification Rate (SLN-IR) and pooled False Negative Rate (FNR) using random-effects model. RESULTS: A total of 45 articles were retrieved by the initial systematic search. 7 out of the 45 studies comprising a total of 332 patients were included in the meta-analysis. The pooled SLN-IR was 93.2% (95% confidence interval [CI], 0.87-0.97; 87% to 97%). Five validation studies were included for pooling the false negative rate and included a total of 211 patients. The pooled FNR was 5.6% (95% confidence interval [CI], 2.9-9.07). CONCLUSION: Fluorescein-guided SLNB is a viable option for detection of lymph node metastases in clinically node negative patients with early breast cancer. It achieves a high pooled Sentinel Lymph Node Identification Rate (SLN-IR) of 93% with a false negative rate of 5.6% for the detection of axillary lymph node metastasis.

Targeted axillary dissection: worldwide variations in clinical practice.

PURPOSE: Targeted axillary dissection (TAD) for the axillary staging of clinically node-positive (cN +) breast cancer patients converting to clinically node negative post neoadjuvant chemotherapy (NAC), has gained popularity due to its minimal false negative rate and low arm morbidity. The aim of this study is to shed more light on the variation in the clinical practice globally in terms of indications and perceived limitations of TAD. METHODS: A panel of expert breast surgeons constructed a structured questionnaire comprising of 18 questions and asked surgeons worldwide for their opinions and routine practice on TAD. The questionnaire was electronically distributed and answers were collected between May 1st and August 1st 2022. RESULTS: Responses included 137 entries from 36 countries. Of them, 73.7% consider TAD for cN + patients planned to receive NAC. Among them, the greatest number of respondents (45%) perform the procedure for tumours up to T3, whereas 27% regardless of T-stage. The majority (42%) perform TAD on patients with 1-3 positive nodes and only 30% consider TAD when matted nodes are present. HER2 positive and Triple Negative subtypes are more likely to undergo TAD than Luminal A and B (86%, 79.1%, 39.5%, and 62.8%, respectively). Maximum acceptable lymph node burden is median 3 nodes for any subtype with a tendency to accept more positive nodes for Triple Negative. CONCLUSION: This study demonstrates the differences in current practice regarding TAD as well as the fact that the biology of the tumour heavily affects the method of axillary staging.

Long-term outcome in patients with nodal-positive breast cancer treated with sentinel lymph node biopsy alone after neoadjuvant chemotherapy.

PURPOSE: Sentinel lymph node biopsy (SLNB) has yet to be accepted as the standard staging procedure in node positive (cN1) breast cancer patients who had clinical complete response in the axilla (cN0) following neoadjuvant chemotherapy (NAC), due to the presumed high false negative rate associated with SLNB in such scenario. This study aimed to determine whether there is a significant difference in the axillary recurrence rate (ARR) and long-term survival in this group of patients, receiving SLNB alone versus axillary lymph node dissection (ALND). METHODS: A retrospective cohort of cN1 patients who were rendered cN0 by NAC from January 2014 to December 2018 were identified from the Asan Medical Center database. Patients' characteristics and outcomes were collected and analyzed. RESULTS: 902 cN1 patients treated with NAC and turned cN0 were identified. 477 (52.9%) patients achieved complete pathological response in the axilla (ypN0). At a median follow up of 65 months, ARR was 3.2% in the SLNB only group and 1.8% in the ALND group (p = 0.398). DFS and OS were significantly worse in patients with ALND as compared to patients with SLNB only (p = 0.011 and 0.047, respectively). We noted more patients in the ALND group had T3-4 tumor. In the subgroup analysis, we showed that in the T1-2 subgroup (n = 377), there was no statistically significant difference in DFS and OS (p = 0.242 and 0.671, respectively) between SLNB only and ALND group. CONCLUSION: Our findings suggest that cN1 patients who were converted to ypN0 following NAC may be safely treated with SLNB only.

Gene expression profiles in clinically T1-2N0 ER+HER2- breast cancer patients treated with breast-conserving therapy: their added value in case sentinel lymph node biopsy is not performed.

PURPOSE: Omitting sentinel lymph node biopsy (SLNB) in breast cancer treatment results in patients with unknown positive nodal status and potential risk for systemic undertreatment. This study aimed to investigate whether gene expression profiles (GEPs) can lower this risk in cT1-2N0 ER+ HER2- breast cancer patients treated with BCT. METHODS: Patients were included if diagnosed between 2011 and 2017 with cT1-2N0 ER+ HER2- breast cancer, treated with BCT and SLNB, and in whom GEP was applied. Adjuvant chemotherapy recommendations based on clinical risk status (Dutch breast cancer guideline of 2020 versus PREDICT v2.1) with and without knowledge on SLNB outcome were compared to GEP outcome. We examined missing adjuvant chemotherapy indications, and the number of GEPs needed to identify one patient at risk for systemic undertreatment. RESULTS: Of 3585 patients, 2863 (79.9%) had pN0 and 722 (20.1%) pN + disease. Chemotherapy was recommended in 1354 (37.8% guideline-2020) and 1888 patients (52.7% PREDICT). Eliminating SLNB outcome (n = 722) resulted in omission of chemotherapy recommendation in 475 (35.1% guideline-2020) and 412 patients (21.8% PREDICT). GEP revealed genomic high risk in 126 (26.5% guideline-2020) and 82 patients (19.9% PREDICT) in case of omitted chemotherapy recommendation in the absence of SLNB. Extrapolated to the whole group, this concerns 3.5% and 2.3%, respectively, resulting in the need for 28-44 GEPs to identify one patient at risk for systemic undertreatment. CONCLUSION: If no SLNB is performed, clinical risk status according to the guideline of 2020 and PREDICT predicts a very low risk for systemic undertreatment. The number of GEPs needed to identify one patient at risk for undertreatment does not justify its standard use.

Positive predictive value of axillary lymph node cortical thickness and nodal, clinical, and tumor characteristics in newly diagnosed breast cancer patients.

PURPOSE: Axillary lymph nodes (LNs) with cortical thickness > 3 mm have a higher likelihood of malignancy. To examine the positive predictive value (PPV) of axillary LN cortical thickness in newly diagnosed breast cancer patients, and nodal, clinical, and tumor characteristics associated with axillary LN metastasis. METHODS: Retrospective review of axillary LN fine needle aspirations (FNAs) performed 1/1/2018-12/31/2019 included 135 axillary FNAs in 134 patients who underwent axillary surgery. Patient demographics, clinical characteristics, histopathology, and imaging features were obtained from medical records. Hypothesis testing was performed to identify predictors of axillary LN metastasis. RESULTS: Cytology was positive in 72/135 (53.3%), negative in 61/135 (45.2%), and non-diagnostic in 2/135 (1.5%). At surgery, histopathology was positive in 84 (62.2%) and negative in 51 (37.8%). LN cortices were thicker in metastatic compared to negative nodes (p < 0.0001). PPV of axillary LNs with cortical thickness ≥ 3 mm, ≥ 3.5 mm, ≥ 4 mm and, ≥ 4.25 mm was 0.62 [95% CI 0.53, 0.70], 0.63 [0.54, 0.72], 0.67 [0.57, 0.76] , and 0.74 [0.64, 0.83], respectively. At multivariable analysis, abnormal hilum (OR = 3.44, p = 0.016) and diffuse cortical thickening (OR = 2.86, p = 0.038) were associated with nodal metastasis. CONCLUSION: In newly diagnosed breast cancer patients, increasing axillary LN cortical thickness, abnormal fatty hilum, and diffuse cortical thickening are associated with nodal metastasis. PPV of axillary LN cortical thickness ≥ 3 mm and ≥ 3.5 mm is similar but increases for cortical thickness ≥ 4 mm. FNA of axillary LNs with cortex < 4 mm may be unnecessary for some patients undergoing sentinel LN biopsy.

Investigating the role of tumour-to-skin proximity in predicting nodal metastasis in breast cancer.

BACKGROUND: Understanding the factors influencing nodal status in breast cancer is vital for axillary staging, therapy, and patient survival. The nodal stage remains a crucial factor in prognostication indices. This study investigates the relationship between tumour-to-skin distance (in T1-T3 tumours where the skin is not clinically involved) and the risk of nodal metastasis. METHODS: We retrospectively reviewed data from 100 patients who underwent neoadjuvant chemotherapy (NACT). Besides patient demographics and tumour variables, a radiologist retrospectively reviewed pre-operative MRI to measure tumour-to-skin distance. R core packages were used for univariate (χ2 and T-Wilcoxon tests) and bivariate logistic regression statistical analysis. RESULTS: Of 95 analysable datasets, patients' median age was 51 years (IQR: 42-61), 97% were symptomatic (rest screen detected), and the median tumour size was 43 mm (IQR, 26-52). On multivariate analysis, increasing invasive tumour size (p = 0.02), ER positivity (p = 0.007) and shorter tumour-to-skin distance (p = 0.05) correlated with nodal metastasis.  HER2 was not included in multivariate analysis as there was no association with nodal status on univariate analysis. In node-positive tumours, as tumour size increased, the tumour-to-skin distance decreased (r = - 0.34, p = 0.026). In node-negative tumours, there was no correlation (r = + 0.18, p = 0.23). CONCLUSION: This study shows that non-locally advanced cancers closer to the skin (and consequent proximity to subdermal lymphatics) are associated with a greater risk of nodal metastasis. Pre-operative identification of those more likely to be node positive may suggest the need for a second-look USS since a higher nodal stage may lead to a change in therapeutic strategies, such as upfront systemic therapy, node marking, and axillary clearance without the need to return to theatre following sentinel node biopsy.

Omission of axillary lymph node dissection for breast cancer patients with three or more positive sentinel lymph nodes.

PURPOSE: The ACOSOG Z0011 (Z11) trial assessed the benefit of axillary dissection (ALND) for breast cancer patients with sentinel lymph node (SLN) metastases; however, Z11 excluded patients with ≥ 3 positive SLNs. We analyzed trends in ALND omission in patients with ≥ 3 positive SLNs. METHODS: Women with ≥ 3 positive SLNs who underwent breast-conserving surgery (BCS) or mastectomy between 2018 and 2020 in the National Cancer Database were included using SLN codes initiated in 2018. Patients with stage IV disease, recurrent breast cancer, and who underwent neoadjuvant chemotherapy were excluded. A multivariable logistic regression model was utilized to determine the proportion who received ALND and factors associated with ALND omission. A subgroup analysis was performed among patients who met the remainder of the Z11 inclusion criteria (BCS, T1/T2 breast cancer). RESULTS: We identified 3654 patients with ≥ 3 positive SLNs. ALND was omitted in 37% of patients, and omission significantly increased from 2018 to 2020 (29% vs. 41%, p < 0.0001). Older age, lower grade tumors, no radiation, non-academic facility, BCS, more SLNs examined and fewer positive SLNs were significantly associated with ALND omission. 942 patients with ≥ 3 positive SLNs met the remainder of the Z11 inclusion criteria. ALND was omitted in 49% of these patients, and omission increased from 2018 to 2020 (44% vs. 49%, p = 0.22). CONCLUSION: Approximately one-third of patients with ≥ 3 positive SLNs do not undergo ALND; omission of ALND increased from 2018 to 2020. Studies assessing oncologic outcomes of patients with ≥ 3 positive SLNs who do and do not receive ALND are required.

Characteristics and risk factors of axillary lymph node metastasis of microinvasive breast cancer.

PURPOSE: To select patients who would benefit most from sentinel lymph node biopsy (SLNB) by investigating the characteristics and risk factors of axillary lymph node metastasis (ALNM) in microinvasive breast cancer (MIBC). METHODS: This retrospective study included 1688 patients with MIBC who underwent breast surgery with axillary staging at the Asan Medical Center from 1995 to 2020. RESULTS: Most patients underwent SLNB alone (83.5%). Seventy (4.1%) patients were node-positive, and the majority had positive lymph nodes < 10 mm, with micro-metastases occurring frequently (n = 37; 55%). Node-positive patients underwent total mastectomy and axillary lymph node dissection (ALND) more than breast-conserving surgery (BCS) and SLNB compared with node-negative patients (p < 0.001). In the multivariate analysis, independent predictors of ALNM included young age [odds ratio (OR) 0.959; 95% confidence interval (CI) 0.927-0.993; p = 0.019], ALND (OR 11.486; 95% CI 5.767-22.877; p < 0.001), number of lymph nodes harvested (≥ 5) (OR 3.184; 95% CI 1.555-6.522; p < 0.001), lymphovascular invasion (OR 6.831; 95% CI 2.386-19.557; p < 0.001), presence of multiple microinvasion foci (OR 2.771; 95% CI 1.329-5.779; p = 0.007), prominent lymph nodes in preoperative imaging (OR 2.675; 95% CI 1.362-5.253; p = 0.004), and hormone receptor positivity (OR 2.491; 95% CI 1.230-5.046; p = 0.011). CONCLUSION: Low ALNM rate (4.1%) suggests that routine SLNB for patients with MIBC is unnecessary but can be valuable for patients with specific risk factors. Ongoing trials for omitting SLNB in early breast cancer, and further subanalyses focusing on rare populations with MIBC are necessary.

Tumor-infiltrating lymphocytes as a predictor of axillary and primary tumor pathological response after neoadjuvant chemotherapy in patients with breast cancer: a retrospective cohort study.

PURPOSE: Tumor-infiltrating lymphocytes (TILs) can predict complete pathological response (pCR) of tumor in the breast but not so well-defined in the axilla after neoadjuvant chemotherapy. Since axillary surgery is being increasingly de-escalated after NACT, we aimed to investigate the relationship between TILs and pCR in the axilla and breast, as well as survival amongst NACT patients. METHODS: Clinicopathological data on patients who underwent NACT between 2013 and 2020 were retrospectively examined. Specifically, pre-TILs (before NACT), post-TILs (after NACT) and ΔTIL (changes in TILs) were assessed. Primary endpoint was pCR and secondary endpoints were breast cancer-free interval (BCFI) and overall survival (OS). RESULTS: Two hundred and twenty patients with nodal metastases were included. Overall axillary and breast pCR rates were 42.7% (94/220) and 39.1% (86/220), respectively, whereas the combined pCR rate was 32.7% (72/220). High pre-TILs (OR 2.03, 95% CI 1.02-4.05; p = 0.04) predicted axillary pCR whereas, high post-TILs (OR 0.33, 95% CI 0.14-0.76; p = 0.009) and increased ΔTILs (OR 0.25, 95% CI 0.08-0.79; p = 0.02) predicted non-axillary pCR. TILs were not a significant predictor for BCFI and OS. CONCLUSIONS: This study supports the potential use of pre-TILs to select initially node-positive patients for axillary surgical de-escalation after NACT.

Breast lymphedema following breast-conserving treatment for breast cancer: current status and future directions.

PURPOSE: To examine the current evidence on breast lymphedema (BL) diagnosis and treatment after breast-conserving surgery, identify gaps in the literature, and propose future research directions. METHODS: A comprehensive literature review was conducted using Ovid, PubMed, and Cochrane, including studies published between 2000 and 2023. References were reviewed manually for eligible studies. Inclusion criteria were as follows: patients who underwent breast conserving treatment (surgery ± radiation) for breast cancer, goals of the paper included analyzing or reviewing BL measurement with ultrasound or tissue dielectric constant, or BL treatment. Twenty-seven manuscripts were included in the review. RESULTS: There is variation in incidence, time course, and risk factors for BL. Risk factors for BL included breast size, primary and axillary surgery extent, radiation, and chemotherapy but require further investigation. Diagnostic methods for BL currently rely on patient report and lack standardized criteria. Tissue dielectric constant (TDC) and ultrasound (US) emerged as promising ambulatory BL assessment tools; however, diagnostic thresholds and validation studies with ICG lymphography are needed to establish clinical utility. The evidence base for treatment of BL is weak, lacking high-quality studies. CONCLUSION: The natural history of BL is not well defined. TDC and US show promise as ambulatory assessment tools for BL; however, further validation with lymphatic imaging is required. BL treatment is not established in the literature. Longitudinal, prospective studies including pre-radiation measurements and validating with lymphatic imaging are required. These data will inform screening, diagnostic criteria, and evidence-based treatment parameters for patients with BL after breast-conserving surgery and radiation.