Changes in Surgical Management of the Axilla Over 11 Years - Report on More Than 1500 Breast Cancer Patients Treated with Neoadjuvant Chemotherapy on the Prospective I-SPY2 Trial

Predictors of mastectomy in breast cancer patients with complete remission of primary tumor after neoadjuvant therapy: A retrospective study

INTRODUCTION

Neoadjuvant therapy (NAT) should increase the rate of breast-conserving surgery (BCS) in non-metastatic breast cancer (BC) patients, especially in those achieving tumor shrinkage. Still, the conversion from a pre-planned mastectomy to BCS in patients responding to NAT is not a widespread standard. We aimed to identify factors influencing surgical choices in this setting.

MATERIALS AND METHODS

We retrospectively collected data of BC patients with complete remission of primitive tumor (ypT0) after NAT, treated with BCS or mastectomy in two Italian breast units. Predictors of mastectomy were explored using logistic regression. Distant recurrence and event-free survival were assessed in the BCS and mastectomy cohort.

RESULTS

243 patients were included, 147 (60.5 %) treated with BCS and 96 (39.5 %) treated with mastectomy. In the mastectomy group, there were more centrally-located, multiple and larger tumors. At univariate regression analysis, central location, baseline tumor extension on ultrasound (US) and magnetic resonance imaging (MRI), multiple foci and clinical stage were significantly associated with the chance of receiving mastectomy. At multivariate analysis, only baseline focality on US and extension on MRI retained significance as predictors of mastectomy. Distant recurrence and event-free survival were significantly longer in patients undergoing BCS.

CONCLUSION

Baseline tumor extension and focality were the main predictors of mastectomy in patients with ypT0 after NAT. However, BCS did not negatively affect survival outcomes in our cohort. An effort should be made to avoid potentially unnecessary mastectomy in this population, aiming at minimizing surgery-associated toxicities and improving patients' quality of life.

The Prevalence of Sentinel Lymph Node Positivity and Implications for the Utility of Frozen Section Diagnosis Following Neoadjuvant Systemic Therapy in Patients with Clinically Node-Negative HER2-Positive or Triple-Negative Breast Cancer

BACKGROUND

Axillary dissection is the standard of care for patients with positive sentinel lymph nodes (SLNs) following neoadjuvant systemic therapy. Frozen section can provide intraoperative information regarding the need for axillary dissection during the index operation. However, there are limited data on the utility of frozen section in patients with clinically node-negative (cN0) HER2-positive or triple-negative breast cancer.

METHODS

We conducted a single-institution observational cohort study including patients with non-inflammatory, cN0, HER2-positive or triple-negative breast cancer treated with neoadjuvant systemic therapy between 2015 and 2019. We estimated the prevalence of SLN positivity and the diagnostic test characteristics of SLN frozen section.

RESULTS

Overall, 662 patients were eligible for inclusion, and 44 patients had one or more positive SLNs (prevalence: 6.6%, 95% confidence interval [CI] 4.9-8.8). There were 490 (74.0%) patients who had intraoperative frozen section, and 19 (3.9%) tested positive among 33 (6.7%) with positive final pathology. Frozen section sensitivity was 57.6% (95% CI 39.2-74.5), specificity was 100% (95% CI 99.2-100), positive predictive value was 100% (95% CI 82.4-100), and negative predictive value was 97.0% (95% CI 95.1-98.4). The sensitivity of frozen section for detection of micrometastases or isolated tumor cells was 35.3% (95% CI 14.2-61.7).

CONCLUSION

In patients with cN0 HER2-positive or triple-negative breast cancer who have been treated with neoadjuvant therapy, positive SLNs are uncommon and frozen section sensitivity is modest. Decisions to defer SLN evaluation to final pathology, which may be reasonable in many settings, can be informed, in part, by these findings.

Contemporary Axillary Surgical Management in Patients with Pathologically Node Positive Disease After Neoadjuvant Chemotherapy: A Survey of Members of the American Society of Breast Surgeons

BACKGROUND

Axillary lymph node dissection (ALND) is increasingly omitted for breast cancer patients with pathologic nodal disease after neoadjuvant chemotherapy (NAC). This study aimed to understand when and why surgeons consider omitting ALND after NAC.

METHODS

The American Society of Breast Surgeons membership was surveyed, and responses were tabulated. To identify patterns, multiple correspondence analyses followed by cluster analysis on coordinates provided by the former were performed. Chi-squared analyses determined whether cluster characteristics were significantly (P < 0.05) associated with omission of ALND.

RESULTS

Of members, 328/2172 (15.1%) completed the survey. Most (60.7%) always offer sentinel lymph node surgery to cN1 patients who respond to NAC, and many (43.9%) sometimes omit ALND in the setting of residual nodal disease. Respondents less often consider omitting ALND with increasing volume of pathologic nodal disease after NAC and are less likely to omit ALND among patients with cN1 disease at presentation than cN0 (P < 0.05 across all volumes). Respondents cited radiation administration (74.1%) and belief that ALND would not improve locoregional (48.2%), distant recurrence or survival (47.6%) outcomes when axillary radiation is administered as reasons to omit ALND. The respondent group comprising male private practice surgeons, practicing ≥ 21 years, consider omitting ALND significantly more frequently.

CONCLUSIONS

Surgeons sometimes consider ALND omission for patients with pathologic nodal disease after NAC but are more likely to do so in cN0 patients and patients with smaller volumes of nodal disease. These decisions are largely based on perceived lack of oncologic benefit despite absence of prospective data supporting this deescalation.

Residual Nodal Burden After Neoadjuvant Chemotherapy in cN1 Breast Cancer Patients with Positive Nodes at Targeted Axillary Dissection

BACKGROUND

Targeted axillary dissection (TAD) facilitates nodal staging in cN1 breast cancer after neoadjuvant chemotherapy (NAC). Completion axillary node dissection (cALND) remains the standard of care for TAD-positive patients. This study investigated factors associated with additional positive nodes at cALND (cALND+) and the impact on the residual cancer burden (RCB).

METHODS

Retrospective review of cN1 breast cancer patients treated with NAC and TAD was conducted from July 2013 to June 2023. The review defined cN1 status by ultrasound (US) and biopsy. Patient, tumor, and treatment characteristics were evaluated. Multivariate analysis was performed to identify factors associated with cALND+, and RCB was calculated.

RESULTS

Of 902 patients who underwent TAD, 554 (61.4%) were TAD-positive. 457 underwent cALND, and 124 (27%) were cALND+ (average 4.1 additional +nodes). The cALND+ patients had larger primary tumors at diagnosis (4 vs 3.5 cm; p = 0.04), more than three suspicious nodes on initial US (30% vs 13%; p ≤ 0.0001), larger residual primary tumors on pathology (median, 3 vs 2.1 cm; p = 0.0004), and more positive TAD nodes (median, 2 vs 1; p ≤ 0.0001). In the multivariate analysis, the factors associated with cALND+ were more than three suspicious nodes on initial US (odds ratio [OR], 2.9; p ≤ 0.0001), more positive TAD nodes (OR, 1.1; p ≤ 0.0001), larger clipped node metastasis (OR, 1.1; p ≤ 0.0001), and larger residual tumor on pathology (OR, 1.1; p = 0.006). Of 65 cALND+ patients with RCB class I or II, 29 (45%) had an increase in RCB based on cALND.

CONCLUSION

Of cN1 breast cancer patients treated with NAC who are TAD-positive, approximately 25% will have additional nodal disease on cALND. In these patients, positive cALND is associated with greater disease burden, which has potential implications for RCB status and prognosis.

Clipping the Positive Lymph Node in Patients with Clinically Node Positive Breast Cancer Treated with Neoadjuvant Chemotherapy: Impact on Axillary Surgery in the ISPY-2 Clinical Trial

BACKGROUND

For patients with clinically node-positive (cN+) breast cancer undergoing neoadjuvant chemotherapy (NAC), retrieving previously clipped, biopsy-proven positive lymph nodes during sentinel lymph node biopsy [i.e., targeted axillary dissection (TAD)] may reduce false negative rates. However, the overall utilization and impact of clipping positive nodes remains uncertain.

PATIENTS AND METHODS

We retrospectively analyzed cN+ ISPY-2 patients (2011-2022) undergoing axillary surgery after NAC. We evaluated trends in node clipping and associations with type of axillary surgery [sentinel lymph node (SLN) only, SLN and axillary lymph node dissection (ALND), or ALND only] and event-free survival (EFS) in patients that were cN+ on a NAC trial.

RESULTS

Among 801 cN+ patients, 161 (20.1%) had pre-NAC clip placement in the positive node. The proportion of patients that were cN+ undergoing clip placement increased from 2.4 to 36.2% between 2011 and 2021. Multivariable logistic regression showed nodal clipping was independently associated with higher odds of SLN-only surgery [odds ratio (OR) 4.3, 95% confidence interval (CI) 2.8-6.8, p < 0.001]. This was also true among patients with residual pathologically node-positive (pN+) disease. Completion ALND rate did not differ based on clip retrieval success. No significant differences in EFS were observed in those with or without clip placement, both with or without successful clip retrieval [hazard ratio (HR) 0.85, 95% CI 0.4-1.7, p = 0.7; HR 1.8, 95% CI 0.5-6.0, p = 0.3, respectively].

CONCLUSION

Clip placement in the positive lymph node before NAC is increasingly common. The significant association between clip placement and omission of axillary dissection, even among patients with pN+ disease, suggests a paradigm shift toward TAD as a definitive surgical management strategy in patients with pN+ disease after NAC.

Omission of Axillary Lymph Node Dissection in Patients with Residual Nodal Disease After Neoadjuvant Chemotherapy

BACKGROUND

Axillary management after neoadjuvant chemotherapy (NAC) is evolving but axillary lymph node dissection (ALND) remains the standard of care for patients with residual nodal disease. The results of the Alliance A011202 trial evaluating the oncologic safety of ALND omission in this cohort are pending but we hypothesize that ALND omission is already increasing.

METHODS

The National Cancer Database was queried to identify patients diagnosed with cT1-3N1M0 breast cancer who underwent NAC and had residual nodal disease (ypN1mi-2) from 2012 to 2021. Temporal trends in omission of completion ALND were assessed annually. Multivariable logistic and Cox regression models were used to identify factors associated with ALND omission and overall survival (OS), respectively.

RESULTS

A total of 6101 patients were included; the majority presented with cT2 disease (57%), with 69% HER2+, 23% triple-negative, and 8% hormone receptor-positive/HER2-. Overall, 34% underwent sentinel lymph node biopsy (SLNB) alone. Rates of ALND were the lowest in the last 4 years of observation. After adjustment, treatment at community centers (vs. academic) and lower pathologic nodal burden were associated with omission of ALND. ALND omission was associated with a higher unadjusted OS (5-year OS: 86% SLNB alone vs. 84% ALND; log-rank p = 0.03), however this association was not maintained after adjustment.

CONCLUSIONS

Despite the impending release of the Alliance A011202 results, omission of ALND in patients with residual nodal disease after NAC is increasing. This practice appears more prominent in community centers and in patients with a lower burden of residual nodal disease. No association with OS was noted.

Axillary management and long-term oncologic outcomes in breast cancer patients with clinical N1 disease treated with neoadjuvant chemotherapy

BACKGROUND

Low false negative rates can be achieved with sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) in breast cancer (BC) patients with clinical N1 (cN1) disease. We examined changes in axillary management and oncologic outcomes in BC patients with cN1 disease receiving NAC.

METHODS

BC patients with biopsy proven cN1 disease treated with NAC were selected from our institutional cancer registry (2014-2017). Patients were grouped by axillary management, axillary lymph node dissection (ALND), SLNB followed by ALND, or SLNB alone. Univariable and multivariable survival analysis for recurrence-free survival (RFS) and overall survival (OS) were performed.

RESULTS

81 patients met inclusion criteria: 31 (38%) underwent ALND, 25 (31%) SLNB + ALND, and 25 (31%) SLNB alone. A SLN was identified in 45/50 (90%) patients who had SLNB. ALND was performed in 25/50 (50%) patients who had SLNB: 18 for a + SLNB, 5 failed SLNB, and 2 insufficient SLNs. 25 patients had SLNB alone, 17 were SLN- and 8 SLN+. In the SLNB alone group, 23/25 (92%) patients received adjuvant radiation (RT). 20 (25%) patients developed BC recurrence: 14 distant (70%), 3 local (15%), 2 regional + distant (10%), and 1 contralateral (5%). In the SLNB alone group, there was 1 axillary recurrence in a patient with a negative SLNB who did not receive RT. Univariable survival analysis showed significant differences in RFS and OS between axillary management groups, ALND/SLNB + ALND vs. SLNB alone (RFS: p = 0.006, OS: p = 0.021). On multivariable survival analysis, worse RFS and OS were observed in patients with TNBC (RFS: HR 3.77, 95% CI 1.70-11.90, p = 0.023; OS: HR 8.10, 95% CI 1.84-35.60, p = 0.006).

CONCLUSIONS

SLNB alone and RT after NAC in BC patients with cN1 disease who have negative SLNs at surgery provides long-term regional disease control. This analysis provides support for the practice of axillary downstaging with NAC and SLNB alone.

De-escalation of Axillary Surgery After Neoadjuvant Therapy

Surgical de-escalation of the axilla has evolved over the past 28 years since the emergence of sentinel lymph node surgery. Well-documented complications of the once standard of care axillary lymph node dissection (ALND), including lymphedema, led physician scientists towards a progressive push to study and incorporate less invasive techniques in the axilla. Many trials have justified oncologic safety of axillary de-escalation in patients who are spared neoadjuvant treatment. The applicability in the neoadjuvant setting, however, is less clear and axillary surgical approaches in this patient population have evolved at a slower pace. This review aims to analyze current data in axillary management for patients undergoing neoadjuvant treatment and to discuss current surgical approaches based on nodal pathologic response.

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.

Does Neoadjuvant Chemotherapy in Clinical T1-T2 N0 Triple-Negative Breast Cancer Increase the Extent of Axillary Surgery?

BACKGROUND

Current management strategies for early-stage triple-negative breast cancer (TNBC) include upfront surgery to determine pathologic stage to guide chemotherapy recommendations, or neoadjuvant chemotherapy (NAC) to de-escalate surgery, elucidate tumor response, and determine the role of adjuvant chemotherapy. However, patients who receive NAC with residual pathological nodal (pN) involvement require axillary lymph node dissection (ALND) as they are Z11/AMAROS ineligible. We aimed to evaluate the impact of NAC compared with upfront surgery on pN status and ALND rates in cT1-2N0 TNBC.

METHODS

The National Cancer Database (NCDB) was queried for women with operable cT1-2N0 TNBC from 2014 to 2019. Demographic, clinicopathologic, and treatment data were collected. Multivariable linear regression analysis was performed to assess the odds of pN+ disease and undergoing ALND.

RESULTS

Overall, 55,624 women were included: 26.9% (n = 14,942) underwent NAC and 73.1% (n = 40,682) underwent upfront surgery. The NAC cohort was younger (mean age 52.9 vs. 61.3 years; p < 0.001) with more cT2 tumors (71.6% vs. 31.0%; p < 0.001), and had lower ALND rates (4.3% vs. 5.5%; p < 0.001). The upfront surgery cohort was more likely to have one to three pathologically positive nodes (12.1% vs. 6.5%; odds ratio [OR] 2.37, 95% confidence interval (CI) 2.17-2.58; p < 0.001) but there was no difference in the likelihood of ALND (OR 1.1, 95% CI 0.99-1.24; p = 0.08).

CONCLUSION

Patients who underwent upfront surgery were more likely to be pN+; however, ALND rates were similar between the two cohorts. Thus, the use of NAC does not result in a higher odds of ALND and the decision for NAC should be individualized and based on modern guidelines and systemic therapy benefits.

Axillary Surgery for Breast Cancer in 2024

Axillary surgery for patients with breast cancer (BC) in 2024 is becoming increasingly specific, moving away from the previous 'one size fits all' radical approach. The goal is to spare morbidity whilst maintaining oncologic safety. In the upfront surgery setting, a first landmark randomized controlled trial (RCT) on the omission of any surgical axillary staging in patients with unremarkable clinical examination and axillary ultrasound showed non-inferiority to sentinel lymph node (SLN) biopsy (SLNB). The study population consisted of 87.8% postmenopausal patients with estrogen receptor-positive, human epidermal growth factor receptor 2-negative BC. Patients with clinically node-negative breast cancer and up to two positive SLNs can safely be spared axillary dissection (ALND) even in the context of mastectomy or extranodal extension. In patients enrolled in the TAXIS trial, adjuvant systemic treatment was shown to be similar with or without ALND despite the loss of staging information. After neoadjuvant chemotherapy (NACT), targeted lymph node removal with or without SLNB showed a lower false-negative rate to determine nodal pathological complete response (pCR) compared to SLNB alone. However, oncologic outcomes do not appear to differ in patients with nodal pCR determined by either one of the two concepts, according to a recently published global, retrospective, real-world study. Real-world studies generally have a lower level of evidence than RCTs, but they are feasible quickly and with a large sample size. Another global real-world study provides evidence that even patients with residual isolated tumor cells can be safely spared from ALND. In general, few indications for ALND remain. Three randomized controlled trials are ongoing for patients with clinically node-positive BC in the upfront surgery setting and residual disease after NACT. Pending the results of these trials, ALND remains indicated in these patients.

Precision Oncology in Breast Cancer Surgery

Outcomes for patients with breast cancer have improved over time due to increased screening and the availability of more effective therapies. It is important to recognize that breast cancer is a heterogeneous disease that requires treatment based on molecular characteristics. Early endpoints such as pathologic complete response correlate with event-free survival, allowing the opportunity to consider de-escalation of certain cancer treatments to avoid overtreatment. This article discusses clinical trials of tailoring treatment (eg, I-SPY2) and screening (eg, WISDOM) to individual patients based on their unique risk features.

[Can we avoid axillary lymph node dissection in patients with node positive invasive breast carcinoma?]

OBJECTIVES

The indications and modalities of breast and axillary surgery are undergoing profound change, with the aim of personalizing surgical management while avoiding over-treatment. To update best practices for axillary surgery, four questions were selected by the Senology Commission of the Collège National des Gynécologues et Obstétriciens Français (CNGOF), focusing on, firstly, the definition and evaluation of targeted axillary dissection (TAD) techniques; secondly, the possibility of surgical de-escalation in case of initial lymph node involvement while performing initial surgery; thirdly, in case of surgery following neo-adjuvant systemic therapy (NAST), and fourthly, contra-indications to de-escalation of axillary surgery to allow access to particular adjuvant systemic therapies.

METHODS

The Senology Commission based its responses primarily on an analysis of the international literature, clinical practice recommendations and national and international guidelines.

RESULTS

Firstly, TAD is a technique that combines excision of clipped metastatic axillary node(s) and the axillary sentinel lymph nodes (ASLNs). The detection rate and sensitivity are increased but it still needs to be standardized and practices better evaluated. Secondly, TAD represents an alternative to axillary clearance in cases of metastatic involvement of a single node that can be resected. Thirdly, neither TAD nor ASLN alone is recommended in France after NAST outside of clinical trials, although it is used in several countries in cases of complete pathological response in the lymph nodes, and when at least three lymph nodes have been removed. Fourthly, as some adjuvant targeted therapies are indicated in cases of lymph node invasion of more than three lymph nodes, the place of TAD in this context remains to be defined.

CONCLUSION

Axillary surgical de-escalation can limit the morbidity of axillary clearance. Having proved that TAD does not reduce patient survival, it will most probably replace axillary clearance in well-defined indications. This will require prior standardization of the method and its indications and contra-indications, particularly to enable the use of new targeted therapies.

Prognostic analysis of cT1-3N1M0 breast cancer patients who have responded to neoadjuvant therapy undergoing various axillary surgery and breast surgery based on propensity score matching and competitive risk model

Background

Sentinel lymph node biopsy (SLNB) in breast cancer patients with positive clinical axillary lymph nodes (cN1+) remains a topic of controversy. The aim of this study is to assess the influence of various axillary and breast surgery approaches on the survival of cN1+ breast cancer patients who have responded positively to neoadjuvant therapy (NAT).

Methods

Patients diagnosed with pathologically confirmed invasive ductal carcinoma of breast between 2010 and 2020 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. To mitigate confounding bias, propensity score matching (PSM) analysis was employed. Prognostic factors for both overall survival (OS) and breast cancer-specific survival (BCSS) were evaluated through COX regression risk analysis. Survival curves were generated using the Kaplan-Meier method. Furthermore, cumulative incidence and independent prognostic factors were assessed using a competing risk model.

Results

The PSM analysis matched 4,890 patients. Overall survival (OS) and BCSS were slightly worse in the axillary lymph node dissection (ALND) group (HR = 1.10, 95% CI 0.91-1.31, p = 0.322 vs. HR = 1.06, 95% CI 0.87-1.29, p = 0.545). The mastectomy (MAST) group exhibited significantly worse OS and BCSS outcomes (HR = 1.25, 95% CI 1.04-1.50, p = 0.018 vs. HR = 1.37, 95% CI 1.12-1.68, p = 0.002). The combination of different axillary and breast surgery did not significantly affect OS (p = 0.083) but did have a significant impact on BCSS (p = 0.019). Competing risk model analysis revealed no significant difference in the cumulative incidence of breast cancer-specific death (BCSD) in the axillary surgery group (Grey's test, p = 0.232), but it showed a higher cumulative incidence of BCSD in the MAST group (Grey's test, p = 0.001). Multivariate analysis demonstrated that age ≥ 70 years, black race, T3 stage, ER-negative expression, HER2-negative expression, and MAST were independent prognostic risk factors for both OS and BCSS (all p < 0.05).

Conclusion

For cN1+ breast cancer patients who respond positive to NAT, the optimal surgical approach is combining breast-conserving surgery (BCS) with SLNB. This procedure improves quality of life and long-term survival outcomes.