Bazan JG, et al. - Patients with pT1-2N1 breast cancer treated with mastectomy ± adjuvant systemic therapy without postmastectomy radiotherapy (PMRT) from 2000 to 2013 were assessed for locoregional failure (LRF) and distant metastases (DM) rates. The wide range of LRF/DM rates suggests patients with pT1-2pN1 to be a heterogeneous group. Specifically, low event rates were seen in patients with pT1 tumors and 1 + LN, and patients with micrometastases. The addition of PMRT would lead to small absolute reductions in LRF and DM among these groups, underscoring the importance of patient selection for PMRT in pT1-2pN1 breast cancer.