HER2-positive patients receiving trastuzumab treatment have a comparable prognosis with HER2-negative advanced gastric cancer patients: a prospective cohort observation.

The monoclonal antibody trastuzumab has brought survival benefit to patients with advanced gastric cancer (AGC) that have human epidermal growth factor receptor 2 (HER2) over expression or amplification. This study was designed to compare the clinical outcomes of HER2-negative and HER2-positive AGC patients with or without trastuzumab treatment. There were three groups of patients enrolled for analysis. Group A was 51 HER2-positive AGC patients treated with trastuzumab and chemotherapy; group B was a matched control group of 47 HER2-positive patients who received chemotherapy only; group C was a matched group of 251 HER2-negative patients who received chemotherapy. All the patients were enrolled at Sun Yat-sen University Cancer Center or Zhongshan Hospital, Fudan University between January 2010 and December 2012. The primary endpoint was overall survival (OS). The Kaplan-Meier method and log-rank test were used for survival analysis. The median duration of follow-up was 13.5 months (range 5-18.6 months). The median OS of these three groups of patients was 14.8 months, 11.3 months and 14.4 months respectively (p < 0.001). The survival difference between group A and B was significant, p < 0.001. Similarly, there was significant difference between group B and C, p < 0.001. Moreover the survival between group A and C was comparable, p = 0.281. The median progression-free survival for these three groups was 7.4, 6.0 and 7.2 months. Multivariate analysis confirmed that trastuzumab treatment was an independent prognostic factor in group A and B patients (p = 0.017). HER2 positive was an independent adverse prognostic factor in group B and C patients (p = 0.013).