Effects of Neoadjuvant Radiotherapy on Postoperative Complications in Rectal Cancer: A Meta-Analysis

OBJECTIVE: Neoadjuvant radiotherapy (nRT) is an important treatment approach for rectal cancer. The relationship, however, between nRT and postoperative complications is still controversial. Here, we conducted a meta-analysis to evaluate such concerns. METHODS: The electronic literature from 1983 to 2021 was searched in PubMed, Embase, and Web of Science. Postoperative complications after nRT were included in the meta-analysis. The pooled odds ratio (OR) was calculated by the random-effects model. Statistical analysis was conducted by Review Manager 5.3 and STATA 14. RESULTS: A total of 23,723 patients from 49 studies were included in the meta-analysis. The pooled results showed that nRT increased the risk of anastomotic leakage (AL) compared to upfront surgery (OR = 1.23; 95% CI, 1.07–1.41; p=0.004). Subgroup analysis suggested that both long-course (OR = 1.20, 95% CI 1.03–1.40; p=0.02) and short-course radiotherapy (OR = 1.25, 95% CI, 1.02–1.53; p=0.04) increased the incidence of AL. In addition, nRT was the main risk factor for wound infection and pelvic abscess. The pooled data in randomized controlled trials, however, indicated that nRT was not associated with AL (OR = 1.01; 95% CI 0.82–1.26; p=0.91). CONCLUSIONS: nRT may increase the risk of AL, wound infection, and pelvic abscess compared to upfront surgery among patients with rectal cancer.