Treatment outcomes of peritoneal carcinomatosis arising from gastric cancer with no measurable disease using systemic chemotherapy.

Abstract

e14558 Background: Although many clinical trials of newly developed chemotherapeutic drugs have been conducted, limited studies have focused on gastric cancer patients specifically diagnosed with peritoneal carcinomatosis (PC) without measurable regions. In the current study, we characterized the outcomes of systemic chemotherapy and prognostic factors for patients with gastric cancer PC, particularly in cases without measurable disease. Methods: Clinical data from 211 gastric cancer PC patients (137 without and 74 with measurable disease) subjected to systemic chemotherapy between January 2000 and December 2010 at a single center were reviewed. Results: Median OS rates of gastric cancer PC patients with no measurable disease were significantly longer than those of patients with measurable disease (18.2 vs 12.0 months, p=0.011). In multivariate analysis, poor PS (Hazard ratio (HR) = 2.33, 95% CI, 1.42-3.8, P=0.001), presence of metastatic lymphadenopathy (LAP) (HR=2.23, 95% CI, 1.42-3.5, p=0.002) and high-grade PC (HR=1.82, 95% CI, 1.09-3.04, p=0.025) were associated with significantly decreased OS. Combined with clinical PC grade and measurability of disease, median OS of patients with low-grade PC without measurable disease was 19.6 months (95% CI, 15.5-23.7 months). Median OS rates of 12.6, 13.7 and 6.8 months were estimated in high-grade PC without measurable disease, low-grade PC with measurable disease, and high-grade PC with measurable disease, respectively. Median OS of low-grade PC patients with no measurable disease was significantly higher than that of patients in all other groups (p=0.001, p=0.029 and p<0.001, respectively). Conclusions: Gastric cancer PC is a heterogeneous disease entity. In our study, clinically low-grade PC without measurable disease was associated with better outcomes than other groups following systemic chemotherapy. According to the carcinomatosis grade, specific groups of patients may benefit from systemic chemotherapy. Despite the difficulties of response assessment, further clinical trials for newer treatment strategies and molecular studies focusing on the heterogeneity of gastric cancer PC should be introduced.