Preoperative versus postoperative chemo-radiotherapy for locally advanced gastric cancer: a multicenter propensity score-matched analysis.

Background: Peri-operative chemo-radiotherapyplayed important rolein locally advanced gastric cancer. Whether preoperative strategy can improve the long-term prognosis compared with postoperative treatment is unclear. The study purpose to compare oncologic outcomes in locally advanced gastric cancer patients treated with preoperative chemo-radiotherapy (pre-CRT) and postoperative chemo-radiotherapy (post-CRT).

Methods: From January 2009 to April 2019, 222 patients from 2 centers with stage T3/4 and/or N positive gastric cancer who received pre-CRT and post-CRT were included. After propensity score matching (PSM), comparisons of local regional control (LC), distant metastasis-free survival (DMFS), disease-free survival (DFS) and overall survival (OS) were performed using Kaplan-Meier analysis and log-rank test between pre- and post-CRT groups.

Results: The median follow-up period was 30 months. 120 matched cases were generated for analysis. Three-year LC, DMFS, DFS and OS for pre- vs. post-CRT groups were 93.8% vs. 97.2% (p = 0.244), 78.7% vs. 65.7% (p = 0.017), 74.9% vs. 65.3% (p = 0.042) and 74.4% vs. 61.2% (p = 0.055), respectively. Pre-CRT were significantly associated with DFS in uni- and multi-variate analysis.

Conclusion: Preoperative CRT showed advantages of oncologic outcome compared with postoperative CRT.

Trial Registration: ClinicalTrial.gov NCT01291407 , NCT03427684 and NCT04062058 , date of registration: Feb 8, 2011.