Omission of sentinel node biopsy in early invasive breast cancer: Does age matter?

e12587 Background: National guidelines have supported omission of sentinel lymph node biopsy (SLNB) in patients >70 years with ER+ early invasive breast cancer. Recent randomized studies (SOUND and INSEMA) support omission of SLNB in younger patients without sacrificing survival outcome. The aim of this study is to evaluate the characteristics of patients with early invasive cancer who had omission of SLNB or would have been eligible to omit SLNB in contemporary times. Methods: Retrospective review of IRB-approved prospective database was performed to identify patients with pathological tumor stage I invasive breast cancer age ≥ 55 years treated between 1/2010-1/2025. Descriptive analysis of clinical, demographic, pathologic, and treatment data was performed. Results: We identified a total of 1987 patients with pathologic T1 invasive breast cancer age ≥55 years or older. The median age of the overall cohort was 67.6 years (range 55- 95.7 years). Of these 1987 patients, a total of 153 (7.7%) had omission of SLNB with (70.5%) aged ≥70 years while 14 (9.6%) were ≤ 60 years of age. In the patients who had SLNB, the nodal positivity was 7.5%. 1588 (80.7%) patients in our study group had lumpectomy and the remainder had mastectomy. In the omission of the SLNB group, 22 patients (14.4%) had a lumpectomy. The majority (71.9%) of patients who had omission of SLNB were diagnosed with ER+/PR+/HER2- breast cancer while 10 patients (6.5%) within this cohort had HER2+ disease and 7 (4.6%) had triple-negative breast cancer. Conclusions: As expected, the majority of the patients who had omission of SLNB biopsy were ≥ 70 years with ER+ invasive cancers during the study period. Only 7.5% of the patients within this study group had nodal positivity, thus lending support to adoption of omission of SLNB in select patients with T1 invasive breast cancer and age ≥ 55 years. Demographic and pathologic characteristics. Variable Total Number of Patients (n=1967) Patients Without Axillary Surgery (n=153) Age 70-100 780 (39.7%) 108 (70.5%) Age < 70 years 1187 (60.3%) 45 (29.4%) Age < 60 years 337 (17.1%) 14 (9.2%) ER+/PR+/HER2- 1357 (69.0%) 110 (71.9%) Triple Negative 126 (6.4%) 7 (4.6%) HER2 Positive 213 (10.8%) 10 (6.5%)