Prognosis of patients with advanced gastric cancer by HER2 status and trastuzumab treatment

Abstract

Background: The purpose of this study was to evaluate the impact of human epidermal growth factor receptor 2 (HER2) status and trastuzumab treatment on the prognosis of patients with advanced gastric cancer (AGC). Methods: We retrospectively analyzed 364 AGC patients who received systemic chemotherapy. To evaluate the impact of trastuzumab exposure during any type of chemotherapy, our analysis used time-varying covariates to avoid a possible lead-time bias. Results: Among the 364 patients, 58 (15.9 %) were HER2-positive. The median overall survival of the HER2-positive patients treated with trastuzumab (n = 43) was significantly longer than that of the HER2-negative patients [n = 306; 24.7 vs. 13.9 months, with an adjusted hazard ratio (HR) of 0.58; 95 % confidence interval (CI), 0.36-0.95; P = 0.03]. Notably, 22 patients continued with trastuzumab beyond the date of progression. By contrast, the HER2-positive patients not treated with trastuzumab (n = 15) showed survival similar to that of the HER2-negative patients (13.5 vs. 13.9 months, with an adjusted HR of 1.04; 95 % CI, 0.52-2.11; P = 0.91). According to the multivariate analysis, exposure to trastuzumab was independently associated with a better prognosis (HR 0.56; 95 % CI; 0.33-0.93; P = 0.026). Conclusions: Recent HER2-positive AGC patients have a better prognosis than HER2-negative patients, particularly when treated with trastuzumab. © 2012 The International Gastric Cancer Association and The Japanese Gastric Cancer Association.