Significant Role of Palliative Gastrectomy in Selective Gastric Cancer Patients with Peritoneal Dissemination: A Propensity Score Matching Analysis.

Objective: The aim of this study was to explore whether palliative gastrectomy is suitable for gastric cancer patients with peritoneal metastasis, and for patients in whom the type of peritoneal metastasis should be selected to receive palliative gastrectomy.

Methods: A total of 747 patients diagnosed with gastric adenocarcinoma with peritoneal metastasis at our centers between January 2000 and April 2014 were retrospectively analyzed. After propensity score matching, the clinicopathologic characteristics and clinical outcomes of patients with peritoneal dissemination were analyzed.

Results: After propensity score matching, the median overall survival (OS) of patients in the gastrectomy group was longer than that for patients in the non-gastrectomy group (11.87 vs. 9.27 months; p = 0.020). Patients who received first-line chemotherapy had a significantly longer median OS than those who did not (11.97 vs. 7.03 months; p < 0.001); among these patients, those undergoing more than eight periods of first-line chemotherapy benefited the most (p < 0.001). Subgroup analyses revealed that patients classified as P1 who were undergoing chemotherapy benefited from gastrectomy (p = 0.024), and patients without multisite metastasis also benefited from gastrectomy with regard to OS (p = 0.007). In the multivariate survival analysis, multisite distant metastasis was the independent poor prognostic factor (p < 0.001), while palliative gastrectomy (p = 0.006) and a period of first-line chemotherapy (p < 0.001) were good prognostic factors. Morbidity rates in the gastrectomy and non-gastrectomy groups were 10.4 and 1.0 %, respectively (p = 0.003); however, no difference in mortality was noted between the two groups (p = 0.590).

Conclusions: Palliative gastrectomy can prolong the survival of P1 patients without multisite distant metastasis when combined with more than five periods, and particularly more than eight periods, of first-line chemotherapy.