Human epidermal growth factor receptor 2 (Her-2) and S-1 adjuvant chemotherapy in stage 2/3 gastric cancer patients who underwent D2 gastrectomy

The trastuzumab for Gastric Cancer study newly defined tumors that were positive for human epidermal receptor-2 (Her-2) and created a Her-2-oriented treatment strategy that is also applicable in the adjuvant setting for stage 2/3 cancers. However, there is currently no information available on the rate of Her-2 positivity and the relapse-free survival (RFS) stratified by Her-2 status in stage 2/3 patients. The Her-2 status, defined by the current standard method, was examined in 100 gastric cancer patients who underwent curative D2 surgery, who were pathologically diagnosed with stage 2/3 cancer, and received adjuvant S-1 chemotherapy between June 2002 and December 2011. Ten of the 100 patients were Her-2 positive. Her-2-positive status was more frequently seen in tumors with a differentiated histology. The 5-year RFS rate was 56.3 % in Her-2-positive cases, and 48.8 % in Her-2 negative cases, which was not significantly different (P = 0.786). The Her-2-positive rate for stage 2/3 gastric cancer patients was low, at only 10 %. Although the RFS was not significantly different based on the Her-2 status, the low positive rate made interpretation difficult. A multi-center study with a large sample size is necessary to clarify the prognostic impact of Her-2 in stage 2/3 gastric cancer patients.