Lisa Allen, MD
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
George Plitas, MD
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Ross Sawka, BS
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Andrea V. Barrio, MD
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Deborah M. Capko, MD
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Daniel Choi, MD
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
.jpg "Stephanie Downs-Canner, MD photo")
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
Andreas Giannakou, MD
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Neha Goel, MD, MPH
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
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
.jpg "Minna K. Lee, MD photo")
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
Kate Pawloski, MD, MPH
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Virgilio Sacchini, MD
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
.jpg "Audree B. Tadros, MD, MPH photo")
Audree B. Tadros, MD, MPH
Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States
Varadan Sevilimedu, MBBS, DrPH
Biostatistics Service, Department of Epidemiology and Biostatistics
Memorial Sloan Kettering Cancer Center
New York, New York, United States
.jpg "Monica Morrow, MD (she/her/hers) photo")
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
Axillary surgery in patients with breast cancer continues to evolve. The SOUND and INSEMA trials showed no difference in regional recurrence or disease-free survival with omission of sentinel lymph node biopsy (SLNB) in cT1-T2N0 patients with a negative axillary ultrasound (US) undergoing breast-conserving surgery (BCS). We prospectively evaluated how often axillary staging can successfully be omitted in postmenopausal, HR+/HER2- patients.
Methods:
From 3/1/24-9/1/25, SLNB was omitted in postmenopausal women age 50-70 years with clinical stage 1, grade 1/2, HR+/HER2- cancers undergoing BCS. After INSEMA was published in December 2024, patients with tumors up to 2.5 cm were included. Normal axillary US was required and multicentric disease was excluded. Patients with grade 3 tumors were excluded to avoid underutilization of CDK4/6 inhibitors without nodal staging. Patients with DCIS at presentation who upgraded to invasive disease and met the above criteria were eligible. Those with tumors on final pathology that were grade 3, ≥ 3cm, or HR- or HER2+ underwent SLNB if multidisciplinary consultation indicated that nodal status would inform adjuvant therapy. Adjuvant systemic and radiation therapies were determined based on primary tumor characteristics and genomic profiling.
Results:
475 patients met inclusion criteria for SLNB omission. Of these, 22 (5%) had an abnormal axillary US and underwent SLNB; 4 (18%) had SLN metastases. 12 patients (2.5%) requested SLNB and 1 had a SLN metastasis. Overall, SLNB was omitted in 441 patients; median age was 63 years, median mammographic tumor size was 0.9 cm, and 74% were grade 2 (Table). 34 (7.7%) patients had high-risk features on surgical pathology (grade 3: n = 20; T > 3 cm: n = 11; HER2+: n = 3), 14 (3.2%) of whom returned for SLNB (grade 3: n = 6; T > 3 cm: n = 6; HER2+: n = 2). Of these, 2 had SLN metastases (T > 3 cm: n = 1; HER2+: n = 1). In 318 patients where initial SLNB was omitted, adjuvant treatment data were available. 305 (96%) have received adjuvant radiotherapy (46% whole breast, 54% partial breast) and 300 (94%) have initiated systemic therapy.
Conclusions:
Adoption of SOUND and INSEMA dramatically reduced the use of SLNB, allowing omission in 97% of postmenopausal patients ≤ age 70 with cT1-2N0, grade 1/2, HR+/HER2- cancers and a normal axillary US. The incorporation of clinical trial results into multidisciplinary consensus-driven practice can effectively de-escalate surgical management of patients with early-stage breast cancer.