Potential Impact of Sentinel Lymph Node Biopsy Omission on Adjuvant Treatment Decisions in Low-Risk Breast Cancer: A Regional Multicenter 775 Patient Review of Current Practice in the United Kingdom.

Abstract

Randomized controlled trials support the omission of sentinel lymph node biopsy (SLNB) in low-risk breast cancer. This study investigates the rate of nodal involvement and associated clinical factors and if the result of SLNB influences adjuvant treatment decisions. All patients diagnosed with ER⁺ HER2^- cT1N0 breast cancer ≥ 50 years were treated at three Glasgow breast cancer centers between 2022 and 2024. All patients underwent axillary ultrasound and underwent primary breast conserving surgery. Data were obtained from a prospective database of all breast cancer patients treated. Statistical analysis was performed using SPSS v.29.02.0. A chi-squared test was performed to compare categorical variables. Overall, 755/775 (97.4%) patients underwent axillary surgery and 82/755 (10.9%) were node positive. Clinical and invasive pathological tumor size was significantly associated with nodal involvement [cT1a 0/19 (0.0%), cT1b 10/191 (5.2%), cT1c 70/545 (12.8%), P = 0.019; pT1a 0/41 (0.0%), pT1b 10/205 (4.9%), pT1c 52/241 (12.3%), pT2 19/82 (23.2%), P < 0.001]. Nodal involvement was significantly associated with the use of partial breast radiotherapy [node negative 262/625 (41.9%) versus node positive 0/81 (0.0%), P < 0.001]. Node-positive patients were significantly more likely to receive aromatase inhibitor therapy versus tamoxifen [75/81 (92.6%) versus 5/81 (6.2%), P < 0.001]. The rate of nodal involvement is low, supporting the omission of SLNB. The result of SLNB influences adjuvant treatment decisions in this low-risk cohort. Although there is enthusiasm to omit SLNB, consideration must be given to this, and omission should be performed in the context of multi-disciplinary discussions.