Venous invasion as a risk factor for recurrence after gastrectomy followed by chemotherapy for stage III gastric cancer

Background: Although adjuvant chemotherapy with S-1 after curative gastrectomy has been performed as a standard treatment for Stage II and III gastric cancer (GC) in Japan, patients with Stage III GC still have a high incidence of recurrence and a poor prognostic outcome. The aim of this study was to investigate risk factors for recurrence in patients with Stage III GC despite of curative gastrectomy followed by adjuvant chemotherapy, suggesting an indicator for more intensive management. Methods: A total of 97 patients with pathological Stage III GC underwent adjuvant chemotherapy after curative gastrectomy between 2001 and 2014, were enrolled in this study. We retrospectively analyzed their hospital records from our hospital. Results: The 5-year relapse-free survival (RFS) rates of patients with pStage III GC were 42.0%. Univariate and multivariate analyses for RFS revealed that venous invasion (v+) was an independent factor predicting a shorter RFS (v + vs. v-, 36.5% vs. 47.4%, P = 0.034, HR 1.82, 95% CI: 1.01-3.37). Venous invasion also predicted a shorter overall survival (OS) (v + vs. v-, 33.7% vs. 50.4%, P = 0.027). Regarding the patterns of recurrence, hematogenous recurrence was significantly occurred in patients with v + GC than those without (P = 0.022). Conclusions: Stage III GC with venous invasion is a high-risk subgroup for hematogenous recurrence after curative surgery followed by adjuvant chemotherapy. More intensive and effective adjuvant chemo and/ or molecular targeted therapy for Stage III GC patients with venous invasion should be considered to improve their outcomes.