Postoperative chemoradiotherapy versus chemotherapy for R0 resected gastric cancer with D2 lymph node dissection: an up-to-date meta-analysis

Background This meta-analysis aims to provide more evidence on the role of postoperative chemoradiotherapy (CRT) for gastric cancer (GC) patients in Asian countries where D2 lymphadenectomy is prevalent. Methods We conducted a systematic review of randomized controlled trials (RCTs), extracted data of survival and toxicities, and pooled data to evaluate the efficacy and toxicities of CRT compared with chemotherapy (CT) after D2 lymphadenectomy. Results A total of 960 patients from four RCTs were selected. The results showed that postoperative CRT significantly reduced loco-regional recurrence rate (LRRR: RR = 0.50, 95 % CI = 0.34–0.74, P = 0.0005) and improved disease-free survival (DFS: HR = 0.73, 95 % CI = 0.60–0.89, P = 0.002). However, CRT did not affect distant metastasis rate (DMR: RR = 0.81, 95 % CI = 0.60–1.08, P = 0.15) and overall survival (OS: HR = 0.91, 95 % CI = 0.74–1.11, P = 0.34). The main grade 3–4 toxicities manifested no significant differences between the two groups. Conclusions Overall, CRT after D2 lymphadenectomy may reduce LRRR and prolong DFS. The role of postoperative CRT should be further investigated in the population with high risk of loco-regional recurrence.