Background: The RxPONDER trial randomized patients with cT1-3N0 hormone receptor-positive, HER2-negative (HR+HER2-) breast cancer and one to three positive nodes and Recurrence Score (RS) < 26 to endocrine therapy (ET) or chemoendocrine therapy (CET) with equivalent survival in postmenopausal women. In current practice, cN0 patients with one or two positive sentinel lymph nodes (SLN) do not undergo axillary lymph node dissection (ALND), raising concerns about applying these data in patients who may have additional nodal disease.
Methods: We identified institutional [Dana-Farber Brigham Cancer Center (DF/BCC), 2016-2020] and national [National Cancer Database (NCDB), 2012-2017] cohorts of women aged 50-75 years with cT1-3N0 HR+HER2- breast cancer and RS < 26 treated with upfront surgery with one to three positive SLN. Axillary nodal burden and outcomes were assessed on the basis of the number of positive nodes and CET use.
Results: A total of 197 and 13,499 HR+HER2- eligible patients with one to three positive SLN and RS < 26 were identified in the DF/BCC and NCDB databases, respectively, and 12.7% of DF/BCC and 32.4% of NCDB patients had ALND. Of these, only 12.0 and 4.9% had more than three total positive nodes, respectively. Rates of CET were 6.6% in DF/BCC and 20.9% in NCDB patients. In the NCDB, similar adjusted 4-year overall survival was seen between patients treated with CET or ET for any number of positive nodes (98.1-99.9%, all p > 0.05).
Conclusions: Postmenopausal women with cT1-3N0 HR+HER2- breast cancer and RS < 26 with one to three positive SLN are unlikely to have more than three total positive nodes. CET decisions should continue to be based on SLN biopsy as ALND is unlikely to change treatment recommendations or outcomes.
© 2022. Society of Surgical Oncology.