Long-term survival analysis of adjuvant chemotherapy with or without trastuzumab in patients with T1, node-negative HER2-positive breast cancer

Purpose: Adjuvant therapy for small, node-negative HER2-positive breast cancer (HER2+ BC) is controversial. We aimed to identify the subgroup that would benefit most from adjuvant chemotherapy and trastuzumab. Experimental Design: We reviewed records of patients with pT1N0M0 HER2+ BC treated at our institution from January 1, 1998, through October 31, 2009. We compared three groups: A, no adjuvant chemotherapy; B, adjuvant chemotherapy only; and C, adjuvant chemotherapy with trastuzumab. We evaluated disease-free survival (DFS), overall survival (OS), distant recurrence-free survival (DRFS), and breast cancer-specific survival (BCSS) in each group. Results: We reviewed 587 consecutive patients with a median follow-up of 123.0 months. The 10-year DFS rate was 81.0%, 65.4%, and 97.3% in groups A, B and C, respectively (P