Positive sentinel node in luminal A-like breast cancer patients-implications for adjuvant chemotherapy?

Background: In luminal A-like breast cancer, the indication for adjuvant chemotherapy still is largely based on lymph nodestatus. Sentinel node (SN) positive patients who are no longer recommended an axillary lymph node dissection (ALND) risk undertreatment, especially if they have >= 4 lymph node metastases (LNMs). Aim: To quantify the group of SN positive luminal A-like patients with >= 4 LNMs and to investigate if the ratio between positive SNs and examined SNs (SN ratio) can provide information of the axillary tumor burden. Material and methods: Nearly 370 patients between 2014-2016 in Western Sweden with a clinically node-negative invasive breast cancer treated with both SNB and subsequent ALND were included. SNB findings were compared to ALND findings and the ability of the SN ratio to describe the axillary tumor burden was evaluated using multivariable analysis. Results: In total,17.6% of patients with luminal A-like tumors had >= 4 LNMs. The SN ratio was statistically significant for predicting >= 4 LNMs among luminal A-like patients (p = .013, OR 1.89 (95% CI 1.14-3.12) per 0.1 increment in SN ratio). Conclusions: One sixth of patients with SN positive luminal A-like tumors risk undertreatment. The SN ratio may aid in identifying many of these patients.