Would 1.0 cm be a more suitable cutoff to subdivide pT1 tumors in hormone receptor-negative and HER2-positive breast cancer?

Background HER2+ and hormone receptor (HoR)‐negative breast cancer usually associated with poor outcome. However, it remained elusive for the prognosis of small (T1a‐T1c) HER2+/HoR‐ breast cancer. The present study retrospectively analyzed the Surveillance, Epidemiology, and End Results (SEER) database to explore the clinicopathological characteristics and prognosis of T1a‐T1c HER2+/HoR‐ breast cancer. Material and Methods Data for patients diagnosed with either HER2‐/HoR+or HER2+/HoR‐ T1a‐T1c breast cancer between 2010 and 2012 were obtained from SEER program. Survival analyses were conducted by Kaplan‐Meier method and Cox proportion hazard regression. Results Totally, 2648 HER2+/HoR‐ and 56387 HER2‐/HoR+T1a‐T1c breast cancer patients were enrolled. There was a clear trend that tumor size had a positive correlation with advanced AJCC stage (P