Survival impact of gastrectomy and chemotherapy on gastric signet ring-cell carcinoma with different metastatic lesions: A population-based study.

Background: A comprehensive understanding of gastric signet ring cell carcinoma (SRCC) is limited. The aim of our study was to analyze metastatic patterns of gastric SRCC and evaluate impacts of gastrectomy and chemotherapy for metastatic gastric SRCC.

Methods: We obtained data of gastric cancer patients between 2010 and 2017 in the Surveillance, Epidemiology, and End Results database. Chi-square tests were used to compare data significance. Kaplan-Meier, Cox proportional hazards regression and Fine-Gray competing risk analysis were used to analyze the difference in the overall survival (OS) and cancer-specific survival (CSS). Propensity-score matching was used to adjust numerical difference.

Results: Among 36,459 eligible gastric cancer patients, 6264 (17.2 %) were SRCC patients. Bone metastasis was more common in SRCC patients than in non-SRCC patients. The multivariate analysis showed that chemotherapy (HR = 0.30, 95 %CI = 0.27-0.33, p < 0.01) and gastrectomy (HR = 0.51, 95 %CI = 0.45-0.59, p < 0.01) were protective prognostic factors in certain stage Ⅳ SRCC patients. For the effect of gastrectomy, survival benefits could be found in patients with liver metastasis. The gastrectomy was not associated with improved OS in patients with lung or multiple metastases. In subgroup analysis, SRCC patients with metastasis who received gastrectomy and chemotherapy (HR = 0.17, p < 0.01; HR = 0.03, p < 0.01) had a better OS and CSS than those who had chemotherapy only (HR = 0.30, p < 0.01; HR = 0.18, p < 0.01).

Conclusion: Our study analyzed the unique metastatic patterns of gastric SRCC and recommended chemotherapy as the first choice in metastatic SRCC. For patients with liver metastasis, gastrectomy plus chemotherapy can be considered.