Sentinel Node Biopsy Should Not be Routine in Older Patients with ER-Positive HER2-Negative Breast Cancer Who Are Willing and Able to Take Hormone Therapy.

BACKGROUND The SSO Choosing Wisely campaign recommended selective sentinel lymph node biopsy (SLNB) in clinically node-negative women aged ≥ 70 years with ER+ breast cancer. We sought to assess the association of SLNB positivity, adjuvant treatment, and survival in a population-based cohort. PATIENTS AND METHODS Women aged ≥ 70 years treated for ER+ HER2- breast cancer between 2010 and 2016 were identified in our prospective provincial database. Overall survival (OS) and breast cancer-specific survival (BCSS) were assessed using Kaplan-Meier analysis. Multivariable logistic regression was used to assess the association of SLNB positivity with use of adjuvant treatments and survival outcomes. RESULTS We identified 2662 patients who met study criteria. SLNB was positive in 25%. Increased use of chemotherapy (ChT), hormone therapy (HT), and radiotherapy (RT) was significantly associated with SLNB positivity. Five-year OS was 86%, and BCSS was 96% with median follow-up of 4.3 years. BCSS was worse with grade 3 disease (HR 4.1, 95% CI 2.1-8.1, p < 0.0001) and better with HT (HR 0.5 95% CI 0.3-0.9, p = 0.01). Patients with a positive SLNB treated without adjuvant therapy had lower BCSS (HR 3.2 95% CI 1.2-8.4, p = 0.017) than those with a negative SLNB, but patients with a positive SLNB treated with any combination of ChT, HT, and/or RT, had similar BCSS to those with a negative SLNB. CONCLUSIONS BCSS in this population was excellent at 96%, and BCSS was similar with negative and positive SLNB when patients received HT. SLNB can be omitted in elderly patients willing to take HT.