Fluoropyrimidine with or without platinum as first-line chemotherapy in patients with advanced gastric cancer and severe peritoneal metastasis: a multicenter retrospective study

BACKGROUND: There is no standard first-line chemotherapy for advanced gastric cancer with severe peritoneal metastasis. Although fluoropyrimidine is often used, its efficacy is limited, and it remains unclear whether combination therapy with platinum improves clinical outcomes. METHODS: This retrospective study involved patients at six Japanese academic hospitals between 2010 and 2016. Patients with advanced gastric cancer and severe peritoneal metastasis were included if they had massive ascites and/or inadequate oral intake requiring intravenous nutritional support. We then compared the efficacy and safety of fluoropyrimidine monotherapy with those of fluoropyrimidine/platinum combination therapy. RESULTS: Compared with the combination therapy group (n = 64), the monotherapy group (n = 65) had worse general health (more patients with elderly age, performance status > 2, and having both massive ascites and inadequate oral intake). Both overall survival (9.0 vs 5.0 months, p < 0.01) and progression-free survival (4.3 vs 2.3 months, p < 0.01) were significantly longer in the combination group, and the significance remained after adjusting for prognostic variables (hazard ratios of 0.47 and 0.41, respectively; p < 0.01). Improvements in ascites and oral intake were also greater in the combination group. Although neutropenia (grade ≥ 3) occurred more frequently with combination therapy, both treatments in this study were tolerable. CONCLUSIONS: Combination therapy with fluoropyrimidine and platinum might be more effective than monotherapy with fluoropyrimidine and was tolerable for patients with advanced gastric cancer and severe peritoneal metastasis.