Chemoradiation versus chemotherapy after D2 gastrectomy: A meta-analysis including randomized and real-world trials.

Abstract

e16590 Background: The ARTIST trial failed to achieve positive result regarding benefit of chemoradiation (CRT) after D2 gastrectomy. In most of clinical guidelines and practices, postoperative CRT has been recommended only for those with R1 resection or lesser extent surgery than D2. Our study is to evaluate oncologic benefit of CRT after D2 gastrectomy, integrating data from randomized clinical trials (RCTs) and real-world studies so far. Methods: Systematic searches for Medline and Embase were performed for controlled trials comparing CRT and chemotherapy (CT) arms after D2 gastrectomy with R0 resection, for gastric cancer. Subgroup analyses were performed including RCTs, and balanced studies without significant difference regarding major clinical indicators. Primary endpoint was disease free survival (DFS), and secondary endpoints included overall survival (OS), locoregional recurrence rate (LRR), distant recurrence rate (DRR), and grade ≥3 complications. Results: A total of 13 studies, comprised of 6 RCTs and 7 non-RCTs, involving 2,603 patients were included. DFS benefit was found in overall pooled analysis [odds ratio (OR): 1.264, p = 0.053, I2= 37.5%], and more evident in subgroup analyses using RCTs (OR: 1.440, p = 0.006, I2= ~0%) and balanced studies (OR: 1.417, p < 0.001, I2= ~0%). OS benefit was not significant. LRR reduction was noted in overall pooled analysis (OR: 0.559, p = 0.012, I2 = 46.1%), and clearer in the subgroup analyses with RCTs (OR: 0.495, p < 0.001, I2= ~0%) and balanced studies (OR 0.472, p < 0.001, I2= 9.2%). Pooled LRR rates were 11.3% (95% confidence interval: 7.5-16.8) and 18.1% (13.1-24.4) in CRT and CT arms. DRR was lower in CRT arms (OR: 0.768, p = 0.023, I2= ~0.0%), but the difference was less significant in subgroup analyses. A grade 5 complication was found in each of the two arms among all studies. Comparison of complications varies and will be shown descriptively in the manuscript. Conclusions: Benefit of DFS and LRR with CRT after D2 gastrectomy was well shown in the present study. Identifying subgroup population mostly benefitable from CRT might yield positive results regarding OS and DRR in future studies.