Clinical Efficacy of Radiotherapy Combined with Surgery for Locally Advanced Gastric Signet-Ring-Cell Carcinoma: A SEER Database Analysis

Background: The objective of this study was to assess the clinical efficacy of radiotherapy combined with surgery for locally advanced gastric signet-ring-cell carcinoma (GSRCC). Methods: Clinical data of patients with locally advanced GSRCC diagnosed by postoperative pathology from 2000-2016 were collected from the US Surveillance, Epidemiology and End Results (SEER) database. All the enrolled patients were divided into three groups according to treatment type: surgery alone (S; N=727), surgery with preoperative radiotherapy (RT+S; N=138), surgery with postoperative radiotherapy (S+RT; N=548). Results: The median overall survival (OS) time in S, RT+S and S+RT group was 19, 26 and 33 months, respectively; the overall survival (OS) rate was 19.5%, 26.9% and 34.0%, respectively; the median cancer-specific survival (CSS) time was 29, 31 and 43 months, respectively; and the CSS rate was 32,4%, 35.3% and 43.6%, respectively. After performing propensity score matching (PSM), it was found that the OS rate was significantly lower in S group than in RT+S or S+RT group (all P<0.05) and the CSS rate was lower in the SA group than in the S+RT group (P<0.0001) while there was no significant difference between S and RT+S groups. The OS and CSS were not significantly different between RT+S and S+RT groups. Cox multivariate analysis showed that radiotherapy was an independent prognostic factor for OS and CSS of locally advanced GSRCC.Conclusions: Compared to surgery alone, surgery combined with preoperative or postoperative radiotherapy is beneficial to the long-term survival of patients with locally advanced GSRCC.