Fluoropyrimidine (F) alone versus F plus platinum (P) as first-line chemotherapy in patients (pts) with advanced gastric cancer (AGC) and severe peritoneal metastasis (SPM): A multicenter observational study.

Abstract

121 Background: The standard 1st-line chemotherapy for AGC pts with SPM has not been established. F alone is generally used for their treatment because of difficulty of hydration for dosing of cisplatin (CDDP) in pts with massive ascites, and has shown limited efficacy. It is unclear whether a combination of F and P (CDDP or oxaliplatin): FP improves their clinical outcome. We therefore investigated the efficacy and safety of FP in comparison with F alone. Methods: This retrospective study comprised of AGC pts with SPM and HER2 negative or unknown tumors who received FP or F as 1st-line chemotherapy between Jul 2010 and Sep 2016 at 6 institutions in Japan. SPM was defined as having massive ascites and/or inadequate oral intake requiring intravenous nutrition support. Overall survival (OS), progression-free survival (PFS), response rate of ascites, improvement rate of oral intake, and safety were compared between two treatment groups. Results: A total of 129 pts (64 in FP group, 65 in F group) were included. Patient characteristics (FP vs F) were as follows: median age, 62 vs 67; PS 0/1/2/3/4 (%), 6/64/25/3/2 vs 8/42/42/8/0; massive ascites/inadequate oral intake/both (%), 61/25/14 vs 35/29/35; number of metastatic sites 1-2/3-5 (%), 77/23 vs 78/22; median serum albumin level (g/ml), 3.1 vs 3.1. OS was significantly longer in FP group than F group (median, 9.0 vs 5.0 months; HR 0.56, 95%CI 0.39-0.82; log-rank p < 0.01); it remained significant upon multivariate analysis adjusting for prognostic variables (HR 0.48, 95% CI 0.32-0.73, p < 0.01). Pts in FP group had significantly better PFS in both uni- and multivariate analyses (median, 4.3 vs 2.3 months; HR 0.44, p < 0.01 and HR 0.40, p < 0.01, respectively). Response rate of ascites (51% vs 17%) and improvement rate of oral intake (64% vs 43%) also were better in FP group (p < 0.01 and p = 0.09, respectively). Toxicities were tolerable in both groups, but grade ≥3 neutropenia was more frequent in FP group (36% vs 11%). Conclusions: FP showed significantly better efficacy than F alone, and it could be a promising option as 1st-line treatment for AGC pts with SPM.