Multidisciplinary Management of the Axilla in Patients with cT1-T2 N0 Breast Cancer Undergoing Primary Mastectomy: Results from a Prospective Single-Institution Series

Intraoperative Pathology Assessment May Lead to Overtreatment of the Axilla in Clinically Node-Negative Breast Cancer Patients Undergoing Upfront Mastectomy

BACKGROUND

Randomized trials have established the safety of observation or axillary radiation (AxRT) as an alternative to axillary lymph node dissection (ALND) in patients with limited nodal disease who undergo upfront surgery. Variability remains in axillary management strategies in cN0 patients undergoing mastectomy found to have one to two positive sentinel lymph nodes (SLNs). We examined the impact of intraoperative pathology assessment in axillary management in a national cohort of AMAROS-eligible mastectomy patients.

METHODS

The National Cancer Database was used to identify AMAROS-eligible cT1-2N0 breast cancer patients undergoing upfront mastectomy and SLN biopsy (SLNB) and found to have one to two positive SLNs, from 2018 to 2019. We constructed a variable defining intraoperative pathology as 'not performed/not acted on' if ALND was either not performed or performed at a later date than SLNB, or 'performed/acted on' if SLNB and ALND were completed on the same day. Adjusted multivariable analysis examined predictors of treatment with both ALND and AxRT.

RESULTS

Overall, 8222 patients with cT1-2N0 disease underwent upfront mastectomy and had one to two positive SLNs. Intraoperative pathology was performed/acted on in 3057 (37.2%) patients. These patients were significantly more likely to have both ALND and AxRT than those without intraoperative pathology (41.0% vs. 4.9%; p < 0.001). On multivariate analysis, the strongest predictor of receiving both ALND and AxRT was use of intraoperative pathology (odds ratio 8.99, 95% confidence interval 7.70-10.5; p < 0.001).

CONCLUSIONS

We advocate that consideration should be made for omission of routine intraoperative pathology in mastectomy patients likely to be recommended postmastectomy radiation to minimize axillary overtreatment with both ALND and AxRT in appropriate patients.

Choice of Mastectomy May Increase the Extent of Axillary Surgery in Women with Breast Cancer

INTRODUCTION

Based on the ACOSOG Z0011 trial, women who undergo breast conservation therapy (BCT) and have limited disease in the axilla on sentinel lymph node (SLN) biopsy do not require axillary lymph node dissection (ALND). In this study we investigate the incidence of ALND in patients undergoing elective mastectomy with limited disease in the axilla to identify how many women may have been spared additional axillary surgery if they chose BCT.

METHODS

All women with invasive breast cancer treated at a single tertiary care breast center from 2010-2018 who were candidates for BCT but elected mastectomy and underwent SLN biopsy were identified through retrospective review of a prospectively maintained database. The primary outcome of interest was the incidence of ALND in women found to have a limited burden of disease in the axilla (1-2 positive SLNs).

RESULTS

The study population comprised 151 patients with invasive breast cancer eligible for BCT who chose mastectomy. On final pathology, 34 patients had 1-2 positive SLNs, and 16 of these patients underwent completion ALND. These 16 patients out of 151 overall lumpectomy candidates electing mastectomy (10.6%) could have been spared ALND if they did not elect mastectomy.

DISCUSSION

BCT candidates electing mastectomy have a 10.6% chance of undergoing more extensive axillary surgery than would have been recommended with BCT alone. The increased risk of undergoing additional axillary surgery should be incorporated into the preoperative discussion for patients choosing between BCT and mastectomy.

Optimizing Axillary Management in Clinical T1-2N0 Mastectomy Patients with Positive Sentinel Lymph Nodes

BACKGROUND

Following publication of the AMAROS trial, we sought to optimize axillary lymph node dissection (ALND) or postmastectomy radiation therapy (PMRT) + axillary radiation (AxRT) utilization in cT1-2N0 patients with 1-2 positive sentinel lymph nodes (SLNs) after mastectomy.

METHODS

In November 2015, our multidisciplinary group implemented a protocol to omit intraoperative SLN evaluation for mastectomy patients with cT1-2N0 breast cancer likely to be recommended PMRT if found to have 1-2 positive SLNs (age ≤ 60 years and/or high-risk features defined as estrogen receptor-negative and/or positive for lymphovascular invasion). We prospectively evaluated axillary management, short-term complications, and oncologic outcomes in patients with 1-2 positive SLNs.

RESULTS

From November 2015 to December 2018, 479 of 560 (85%) cT1-2N0 breast cancers treated with mastectomy were potential candidates for PMRT. Intraoperative SLN evaluation was omitted in 344 (72%), thus following the protocol. Overall, 121 cases had 1-2 positive SLNs: 17 (14%) were managed with observation, 5 (4%) PMRT alone, 59 (49%) PMRT + AxRT, 16 (13%) ALND alone, and 24 (20%) ALND + PMRT. Protocol compliance resulted in less ALND (8% vs. 24%) and less ALND + PMRT (9% vs. 41%, p < 0.01). At median follow-up of 24 months, there was one regional and four distant recurrences, with no regional recurrences or differences in disease-free survival in patients treated with ALND versus PMRT + AxRT (100% vs. 98%, p = 0.67). Similarly, there were no differences in complication rates (p = 0.18).

CONCLUSIONS

Omitting intraoperative SLN evaluation in cT1-2N0 mastectomy patients who would be candidates for PMRT if found to have positive nodes decreased rates of ALND and minimized use of ALND + PMRT without compromising outcomes.

A National Survey of Breast Surgeons and Radiation Oncologists on Contemporary Axillary Management in Mastectomy Patients

BACKGROUND

Management of axillary lymph nodes in breast cancer has undergone significant change over the past decade through landmark clinical trials. This study aimed to assess national practice patterns in axillary management in patients undergoing upfront mastectomy and examines what guides provider recommendations.

METHODS

A national case-based survey study was performed of surgeons and radiation oncologists from July to August 2020. Surgeons were identified through the American Society of Breast Surgeons (ASBrS) after review and approval by the ASBrS Research Committee, and radiation oncologists were identified through an institutional database. Both descriptive and comparative statistical analyses were performed.

RESULTS

Overall, 994 providers responded-680 surgeons and 314 radiation oncologists. Surgeons were older and in practice longer (p < 0.05) and treated a higher percentage of breast patients (81% vs. 40%, p < 0.001). Most surgeons were hospital-employed (43%), whereas most radiation oncologists were in private practice (40%; p < 0.001). Fifty-two percent of surgeons routinely send sentinel lymph nodes (SLNs) for frozen section (52%) during mastectomy, of which 78% proceed directly to axillary lymph node dissection (ALND) if positive. There was significant variability in treatment recommendations between the two groups among the hypothetical cases (p < 0.001). In the setting of low disease burden in the SLNs, > 30% of surgeons recommended ALND, while radiation oncologists recommend axillary radiotherapy over axillary clearance (p < 0.001).

CONCLUSION

There is significant heterogeneity in the management of the axilla in mastectomy patients with pathologically positive SLNs, both between and among surgeons and radiation oncologists. Efforts should be made to assist both groups in identifying de-escalation opportunities to ensure that mastectomy patients with positive SLNs are treated appropriately.

A Prognostic Risk Stratification Model to Identify Potential Population Benefiting From Postmastectomy Radiotherapy in T1-2 Breast Cancer With 1-3 Positive Axillary Lymph Nodes

Background and Objectives

To establish a prognostic stratification nomogram for T1–2 breast cancer with 1–3 positive lymph nodes to determine which patients can benefit from postmastectomy radiotherapy (PMRT).

Methods

A population-based study was conducted utilizing data collected from the Surveillance, Epidemiology, and End Results database. Chi-square test or Fisher exact test was used to compare the distribution of characteristics. Cox analysis identified significant prognostic factors for survival. A prognostic stratification model was constructed by R software. Propensity score matching was applied to balance characteristics between PMRT cohort and control cohort. Kaplan-Meier method was performed to evaluate the performance of stratification and the benefits of PMRT in the total population and three risk groups.

Results

The overall performance of the nomogram was good (3-year, 5-year, 10-year AUC were 0.75, 0.72 and 0.67, respectively). The nomogram was performed to excellently distinguish low-risk, moderate-risk, and high-risk groups with 10-year overall survival (OS) of 86.9%, 73.7%, and 62.7%, respectively (P<0.001). In the high-risk group, PMRT can significantly better OS with 10-year all-cause mortality reduced by 6.7% (P = 0.027). However, there was no significant survival difference between PMRT cohort and control cohort in low-risk (P=0.49) and moderate-risk groups (P = 0.35).

Conclusion

The current study developed the first prognostic stratification nomogram for T1–2 breast cancer with 1–3 positive axillary lymph nodes and found that patients in the high-risk group may be easier to benefit from PMRT.

Locoregional Management of the Axilla in Mastectomy Patients with One or Two Positive Sentinel Nodes: The Role of Intraoperative Pathology

INTRODUCTION

Controversy exists regarding optimal management of the axilla in clinically node-negative (cN0) mastectomy patients with one or two positive sentinel lymph nodes (+SLNs). We evaluated the influence of frozen-section pathology on axillary management and recurrence.

PATIENTS AND METHODS

We studied cN0 breast cancer patients treated from 2008 to 2018 with mastectomy and SLN surgery with one or two +SLNs. Patients with one or two +SLNs identified on frozen-section intraoperatively (FS+SLN) were compared to those with one or two +SLNs not detected by frozen section (FS-SLN). Recurrence rates were estimated using the Kaplan-Meier method.

RESULTS

Of 2295 cN0 mastectomy patients, 338 patients had one or two +SLNs: 108 (32%) FS-SLN and 230 (68%) FS+SLN. In the FS+SLN cases, completion axillary lymph node dissection (cALND) was more frequent (97% vs. 39%; P < .001), and median SLN metastasis size (5 vs. 1.3 mm; P < .001) and likelihood of positive non-SLNs (31% vs. 14%; P = .02) were greater compared with FS-SLN cases. Across all 338 patients, 40% had SLN surgery alone, and 47% of cALND patients received post-mastectomy radiation therapy (PMRT). At a median follow-up of 61 months, no axillary recurrences were observed among FS-SLN patients. Among FS+SLN patients, 97% proceeded to cALND but 49% avoided PMRT; three regional nodal recurrences were observed (all in patients treated with cALND, of whom two received PMRT).

CONCLUSION

Mastectomy patients with one or two FS+SLNs have a higher nodal disease burden than FS-SLN patients. The majority of FS+SLN patients underwent cALND, and 51% received PMRT with very low 5-year regional nodal recurrence rates. A substantial proportion of FS-SLN patients successfully avoided both cALND and PMRT. Frozen-section pathology analysis can guide de-escalation of axillary management.

Uptake of Breast Cancer Clinical Trials at Minority Serving Cancer Centers

BACKGROUND

Most minorities receive cancer care at minority-serving hospitals (MSHs) that have been associated with disparate treatment between Black and White patients.

OBJECTIVE

Our aim was to examine the uptake of clinical trials that have changed axillary management in breast cancer patients at MSH and non-MSH cancer centers.

METHODS

The National Cancer Database was used to identify patients eligible for the American College of Surgeons Oncology Group Z0011 and Z1071 trials, and mastectomy patients fulfilling the European AMAROS trial. Uptake of trial results (omission of axillary lymph node dissection) was analyzed between patients treated at MSHs and non-MSHs and adjusted for patient, tumor, and facility factors. MSHs were defined as the top decile of hospitals according to the proportion of Black and Hispanic patients treated.

RESULTS

Of 7167 patients eligible for Z0011, 4546 for Z0171, and 9433 for AMAROS from 2015 to 2016, clinical trial uptake was seen in 1195 (74.6%) MSH and 4056 (72.9%) non-MSH patients (p = 0.173) for Z0011, 588 (41.9%) MSH and 1366 (43.5%) non-MSH patients for Z1071 (p = 0.302), and 272 (11.7%) MSH and 996 (14.0%) non-MSH patients (p = 0.005) for AMAROS. On adjusted analyses, MSH status was not significant for uptake of any of the three trials. Black race, socioeconomic status, and insurance were not associated with clinical trial uptake.

CONCLUSION

The uptake of three landmark clinical trials of axillary management in breast cancer was not different at MSH and non-MSH centers despite adjustment for social determinants of health. At the Commission on Cancer-accredited centers in this analysis, MSH status did not affect the uptake of evidence-based care.

Nomogram-based estimate of axillary nodal involvement in ACOSOG Z0011 (Alliance): validation and association with radiation protocol variations

PURPOSE

A substantial proportion of patients enrolled on ACOSOG Z0011 received protocol-deviant radiation treatment. It is currently unknown whether these deviations involved the use of more extensive fields in patients at higher nomogram-predicted risk.

METHODS

We used the M.D. Anderson (MDA) and Memorial Sloan-Kettering (MSK) nomograms to estimate risk of additional positive axillary nodes using surgical pathology information. In the control arm, we compared axillary dissection (AD) findings to nomogram-predicted estimates for validation. We used logistic regression to evaluate whether nomogram-estimated higher risk of nodal involvement was associated with high tangent (HT) or supraclavicular (SCV) radiation fields for patients with known radiation field design.

RESULTS

552/856 (64.5%) had complete details for the MDA nomogram. Mean MDA risk estimate in both treatment arms was 23.8%. Estimated risk for patients on the AD arm with positive nodes was 25.9%. Higher risk estimate was associated with additional positive nodes in the AD arm (OR 1.04, 95% CI 1.02-1.06, p < 0.0001). We observed significant association with higher MDA nomogram-estimated risk and SCV radiation (OR 1.07, 95% CI 1.04-1.10, p < 0.0001) but not HT (OR 0.99, 95% CI 0.96-1.02, p = 0.52) The MSK nomogram had similar associations.

CONCLUSION

MDA and MSK nomogram risk estimates were associated with lymph node risk in ACOSOG Z0011. Radiation oncologists' use of differing radiation fields were associated with treating higher risk patients. ClinicalTrials.gov id: NCT00003854.

Axillary management for young women with breast cancer varies between patients electing breast-conservation therapy or mastectomy

PURPOSE

Axillary treatment strategies for the young woman with early-stage, clinically node-negative breast cancer undergoing upfront surgery found to have 1-3 positive sentinel lymph nodes (SLNs) differ significantly after BCT and mastectomy. Here we compare axillary lymph node dissection (ALND) and regional nodal irradiation (NRI) rates between women electing breast-conservation therapy (BCT) versus mastectomy.

METHODS

From 2010 to 2016, women age < 50 years with clinical T1-T2N0 breast cancer having upfront surgery and found to have a positive SLN were identified. ALND and/or NRI receipt were compared between groups.

RESULTS

192 women undergoing BCT and 165 undergoing mastectomy were identified (median age: 44 years). 5.2% (10/192) of women undergoing BCT had an ALND versus 87% (144/165) of women undergoing mastectomy (p < 0.01). NRI was given to 48% (78/165) of mastectomy patients compared to 30% (57/192) of BCT patients (p < 0.01). Of the 75 mastectomy patients with 1-2 total positive lymph nodes after completion ALND, 44% received NRI. Women undergoing mastectomy were significantly more likely to receive both ALND and NRI than women undergoing BCS (45% vs 6%, p < 0.01).

CONCLUSION

Young cT1-2N0 breast cancer patients found to have 1-3 SLN metastases received ALND, NRI, and combined ALND/NRI more frequently if they elected mastectomy over BCT. Use of both ALND and postmastectomy radiotherapy (PMRT) in this population could be reduced in the future by omitting ALND in patients for whom the need for PMRT is clear with the finding of 1-2 SLN metastases.

Can Tumor-Infiltrating Lymphocytes (TILs) Be a Predictive Factor for Lymph Nodes Status in Both Early Stage and Locally Advanced Breast Cancer?

The status of axillary lymph nodes is an important prognostic factor in the outcome of breast cancer tumors. New trials changed the attitude towards axillary clearance. In the era of development of new immune therapies for breast cancer, it is important to identify a biomarker that can predict lymph node status. Tumor-infiltrating lymphocytes (TILs) are a valuable indicator of the immune microenvironment that plays the central role in new anticancer drugs. Although the correlation between TILs and response to chemotherapy was established by previous studies, our retrospective study investigated the correlation between TILs and lymph node status. We analyzed data on 172 patients. According to stage, patients were divided in two groups: patients who underwent primary surgical treatment (breast-conserving or mastectomy and sentinel lymph node (SLN) biopsy +/− axillary clearance in conformity with lymph node status) and patients who received chemotherapy prior to surgical treatment (breast-conserving or mastectomy + axillary clearance). We showed a good inverse correlation between TILs and lymph nodes status for both early stage and locally advanced breast cancers. Moreover, TILs are a predictor for positive lymph nodes in the axilla in patients undergoing axillary clearance after SLN biopsy, with no statistical difference between the intrinsic or histological subtype of breast cancers. We also obtained a significant correlation between TILs and response to chemotherapy with no significative difference according to histological subtype. Although further data have still to be gathered before meeting the criteria for clinical utility, this study demonstrates that TILs are one of the most accredited forthcoming biomarkers for breast cancer (BC) patients.