ESMO Asia Virtual Congress 2020

Abstract 139P

Background

No specialized prognosis model for gastric cancer patients with peritoneal metastasis (GCPM) exists for intraoperative clinical decision-making. This study aims to establish a new prognostic model to provide individual treatment decisions for GCPM.

Methods

This retrospective analysis included 324 GCPM diagnosed pathologically by laparoscopy from January 2007 to January 2018 who were randomly assigned to different sets (227 in the training set and 97 in the validation set). A nomogram was established from preoperative and intraoperative variables determined by the Cox model. The peritoneal metastasis nomogram (PMN), was compared with the 15th peritoneal metastasis staging system (P1abc) for its predictive ability and clinical applicability.

Results

The median survival time was 8 (range, 1-90) months. In the training set, each PMN substage had significantly different survival curves (P<0.001), and the PMN was superior to P1abc based on the results of time-dependent receiver operating characteristic curve, C-index, Akaike information criterion and likelihood ratio chi-square analyses. In the validation set, the PMN was also better than P1abc in terms of its predictive ability. Of the PMN1 patients, those undergoing palliative resection (PR) had better OS than those undergoing exploratory surgery (ES) (P<0.05). Among the patients undergoing ES, those who received chemotherapy exhibited better OS than those who did not (P<0.05). Among the patients with PR, only PMN1 patients exhibited better OS following chemotherapy (P<0.05).