P12. Sentinel lymph node biopsy after neoadjuvant chemotherapy is accurate in patients presenting with locally advanced breast cancer

Thursday, March 5, 2026

11:49 AM - 11:56 AM MST

Location: 301A

Primary Presenter(s)

Andrea V. Barrio, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Slides

Co-Author(s)

Starr Mautner, MD

Breast Service, Department of Surgery
Miami Cancer Institute
Miami , Florida, United States
DC

Deborah M. Capko, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
DC

Daniel Choi, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Stephanie Downs-Canner, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Mahmoud B. El-Tamer, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
AH

Alexandra S. Heerdt, MD, MPH

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Laurie J. Kirstein, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Minna K. Lee, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Anita Mamtani, MD (she/her/hers)

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Giacomo Montagna, MD, MPH

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Tracy Ann B. Moo, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
GP

George Plitas, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
VS

Virgilio Sacchini, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Audree B. Tadros, MD, MPH

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
EC

Elizabeth Cooney, MPS

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
AP

Alison Pellecchia, MPH

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
VS

Varadan Sevilimedu, MBBS, DrPH

Biostatistics Service, Department of Epidemiology and Biostatistics
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Monica Morrow, MD (she/her/hers)

Chief, Breast Service, Department of Surgery; Anne Burnett Windfohr Chair of Clinical Oncology; Vice President, Women in Science and Medicine, MSKCC; Professor of Surgery, Weill Cornell Medical College of Cornell University
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Introduction: In patients presenting with locally advanced breast cancer defined as skin/chest wall involvement (cT4) and/or heavy nodal burden (cN2/3), the accuracy of sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) is uncertain. We performed a prospective, single-arm clinical trial to determine the false-negative rate (FNR) of SLNB after NAC in this group.

Methods: Patients with cT4 and/or cN2/N3 breast cancer receiving NAC with a nodal clinical complete response (cN0) on physical exam were eligible for enrollment. SLNB was performed with dual tracer mapping; nodal clipping was not required, but those with clipped nodes underwent specimen X-ray of the retrieved SLNs. All patients had a completion ALND. Target accrual was 150 patients. FNR calculations were based on the patients having ≥ 3 SLNs removed and those with < 3 SLNs in whom the clipped node was retrieved as an SLN. We anticipated 84 patients would meet these criteria, and that 47 would have residual disease after NAC (nodal pCR rate 45%). Assuming a true FNR of 10%, we estimated this sample size would allow estimation of FNR within a margin of error (95% CI half-width) of +/- 8.6%.

Results:

From 8/2017-6/2025, 429 patients with cT4 and/or cN2/3 disease were screened for eligibility prior to receiving NAC at 2 participating sites. The 347 (81%) who became cN0 after NAC were eligible, and 154 enrolled on study. Prior to surgery, 16 patients withdrew, resulting in 138 evaluable patients. Median age was 49 years (IQR 42, 58); 44% of patients had inflammatory breast cancer (cT4d), 24% had other cT4, 12% had cN2, and 20% had cN3 disease. Most had HER2 positive (37%) or triple negative (31%) breast cancer, and 64 (46%) had a clipped node. At least 1 SLN was identified in 104 patients (75%), with no patient or clinical factors associated with failure to map. Of 104 patients, 21 had 1-2 SLNs retrieved and 83 had either ≥ 3 SLNs (n = 78) or 1-2 SLNs with a clipped node retrieved (n = 5). Of 83 patients with adequate mapping eligible for FNR calculation, the nodal pCR rate was 46%; of 45 (54%) with residual disease after NAC, 1 false-negative SLN was observed yielding an SLN FNR of 2.2% (95% CI, 0.1, 13.2) (Table).

Conclusions:

In a prospective cohort of patients with locally advanced breast cancer, the SLN identification rate was 75%: lower than the rate observed in patients with cN1 disease. Notably, the FNR among those with adequate mapping was < 10%, suggesting that SLNB may be an appropriate method to stage the axilla in this cohort.

Learning Objectives:

State the SLN identification rate in patients with locally advanced breast cancer.
Report the nodal pathologic complete response rate for patients for locally advanced breast cancer treated with neoadjuvant chemotherapy.
State the FNR of SLNB in patients with LABC who had “adequate mapping”(i.e.,≥3 SLNs removed and those with <3 SLNs in whom the clipped node was retrieved as an SLN).