RESUMEN
Objective: To evaluate the clinical efficacy and safety of neoadjuvant chemoradiotherapy (nCRT) versus neoadjuvant radiotherapy (nRT) for patients with stages II-III rectal cancer. Methods: A computer-based online search of PubMed, EMBase, Cochrane Library, China Journal Full-text Database, Wanfang Database and Chinese sci-tech periodical full-text database was performed to include randomized controlled trials (RCTs) about nCRT vs nRT (including neoadjuvant short-course radiotherapy, nSRT) in patients with stages II-III rectal cancer in accordance with the inclusion and exclusion criteria. The relevant literatures and conference proceedings were also manually searched to include eligible RCTs. After evaluating the quality of included trials and extracting data, the data analysis was conducted using RevMan 5.2 software. Results: A total of six randomized controlled trials (RCTs) involving 2 602 patients with stages II-III rectal cancer were included. The results of Meta-analysis showed that the nCRT group had higher radical resection rate (odds ratio: 1.62, 95% confidence interval: 1.14-2.30; P = 0.008), pathological complete response rate (odds ratio: 3.17, 95% confidence interval: 2.28-4.40; P < 0.000 01), and rate of severe side effects (grades 3-4) (odds ratio: 2.66, 95% confidence interval: 1.29-5.46; P = 0.008), as compared with nRT group. The five-year local recurrence (LR) rate in the nCRT group was obviously lower than that in the nRT group (odds ratio: 0.51, 95% confidence interval: 0.39-0.67, P < 0.000 01). Regarding nCRT vs nSRT, the radical resection rate (odds ratio: 2.40, 95% confidence interval: 1.25-4.63; P = 0.009) and the pathological complete response rate (odds ratio: 4.28, 95% confidence interval: 1.72-10.68, P = 0.002) were also higher in the nCRT group than those in the nSRT group. Furthermore, there were no differences in two-, three- and five-year survival rates between nCRT and nRT groups (P < 0.05). Conclusion: As compared with nRT, the nCRT can obviously improve the radical resection rate and complete pathologic response rate, and reduce the local recurrence rate in patients with stages II-III rectal cancer, but it can cause more severe toxicities.