Intraoperative radiotherapy in gastric and esophageal cancer: meta-analysis of long-term outcomes and complications.

INTRODUCTION: The treatment effects of intraoperative radiotherapy (IORT) for gastric and esophageal cancer remain uncertain. We therefore performed meta-analyses to investigate whether IORT was associated with more favorable oncologic outcomes when compared to non-IORT for patients who have gastric or esophageal cancer. EVIDENCE ACQUISITION: PubMed, Embase, and the references of relevant studies were systematically searched up to March 2016. Outcomes were analyzed with fixed-effect or random-effect models, and the meta-analysis was completed with odds ratio (OR), hazards ratio (HR), and 95% confidence intervals (CI) as effect values. EVIDENCE SYNTHESIS: Eleven studies were included, nine for gastric cancer and two for esophageal cancer. The studies included 1581 patients, 570 in the IORT group and 1011 in the control group. There was no significant difference in overall survival (OS) between the IORT group and control group (HR=0.91, 95% CI: 0.73-1.13; P=0.38). Two subgroups based on cancer type also had the similar results (gastric group: HR= 0.98, 95% CI: 0.78-1.24, P=0.87; esophagus group: HR=0.63, 95% CI: 0.37-1.05, P=0.08). Besides, IORT showed favorable effects for patients with cancer in stage II and stage III and had the advantage of loco-regional control. Regarding the complications, the occurrence rate had no significant difference between the IORT group and control group (OR=1.15; 95% CI: 0.77-1.72; P=0.50). CONCLUSIONS: According to our meta-analysis, IORT did not extend the OS in gastric cancer and esophageal cancer patients, but had a favorable effect for specific stage patients to show loco-regional control, and did not increase the risk of complications.