Abstract
PURPOSES: Trastuzumab is known to be effective for early and advanced stages of breast cancer but optimal duration for early-stage breast cancer (EBC) is not well known. We evaluated the efficacy and toxicity of 9- and 52-week trastuzumab therapy for EBC retrospectively. METHODS: In this multicenter study, the medical records of all patients with EBC were analyzed in 8 centers retrospectively. Totally consecutive, 479 female patients who received trastuzumab in the adjuvant treatment were evaluated for disease-free survival (DFS), overall survival (OS), efficacy, and toxicity. RESULTS: There were 181 (37.8 %) and 298 (62.2 %) patients in the 9- and 52-week trastuzumab groups, respectively. Median follow-up was 30.6 months (5.7-68.9) in the 9-week trastuzumab group and 29.3 months (5.9-59.6) in the 52-week trastuzumab group. Thirty-six month DFS was 90 and 85 % (P = 0.132) in the 9- and 52-week trastuzumab treatment groups, respectively, and 36-month OS was 96 and 97 % in the 9- and 52-week trastuzumab groups, respectively (P = 0.779). Symptomatic cardiotoxicity was observed in 1 (0.6 %) patient in the 9-week trastuzumab group and in 4 (1.3 %) patients in the 52-week trastuzumab group. CONCLUSIONS: In this study, similar outcomes were found in the 9- and 52-week trastuzumab treatment groups.