Curative gastrectomy and adjuvant chemotherapy using S-1 is a standard treatment for stage II/III gastric cancer in Japan. The purpose of the present study was to evaluate the prognostic relevance of fibroblast growth factor receptor (FGFR)2 expression in patients with stage II/III gastric cancer that underwent postoperative adjuvant chemotherapy with S-1. Formalin-fixed paraffin-embedded surgical specimens were retrospectively examined in 167 patients with stage II/III gastric cancer that underwent curative gastrectomy followed by adjuvant S1 chemotherapy. FGFR2 expression was measured using immunohistochemistry (IHC) staining. The IHC results for FGFR2 were as follows: Grade 1+, 32; grade 2+, 80; grade 3+, 55 patients. The FGFR2 expression level was not significantly associated with relapse-free or overall survival rates. However, in the diffuse type, the FGFR2 expression level tended to be negatively correlated with relapse-free survival. In particular, the proportion of patients who recurred >5 years following surgery was significantly larger in the FGFR2 grade 3+ group than in the grade 1+, 2+ group (4/22 vs. 1/35; P=0.047). The recurrent sites of long-term failure were mostly peritoneum among the diffuse type. To the best of our knowledge, the present study indicated for the first time that FGFR2 could predict long-term failure of adjuvant S-1 chemotherapy in curative advanced gastric cancer. There was no interaction between FGFR2 expression and patient survival outcomes in stage II/III gastric cancer. Patients with FGFR2 3+ in stage II/III gastric cancer should carefully be followed-up for >5 years after surgery.
Keywords: FGFR2; S-1; gastric cancer; recurrence timing; survival outcomes.