Comparison of the effect of postoperative radiotherapy with surgery alone for esophagus squamous cell carcinoma patients: A meta-analysis

BACKGROUND: This meta-analysis was conducted to evaluate the effect of postoperative radiotherapy for patients having esophagus squamous cell carcinoma after radical surgery. METHODS: A comprehensive research was performed in Pubmed, Embase and Cochrane Library electronic databases from inception until December 10, 2017. We collected all published full articles about comparison of surgery plus postoperative radiotherapy with surgery alone. RESULTS: Four randomized-controlled trials (RCTs) with 1050 participants and 8 non-randomized-controlled trials with 3248 participants were included and evaluated separately. The risk ratio rate and its 95% confidence interval (CI) were calculated. Both RCTs and non-randomized-controlled trials (NRCTs) groups showed a significant increase in 3-year overall survival (OS) rate (RR(RCT) = 0.89, 95% CI: 0.80–0.99; RR(NRCT) = 0.82, 95% CI: 0.76–0.88) and decrease locoregional recurrence rate (RR(RCT) = 0.53, 95% CI: 0.43–0.66; RR(NRCT) = 0.47, 95% CI: 0.32–0.69) after postoperative radiotherapy compared with surgery alone. The 5-year OS rate in the group of NRCTs was markedly enhanced (RR = 0.87, 95% CI: 0.82–0.92), while that of the RCTs group was not enhanced in a significant way (RR = 0.84, 95% CI: 0.70–1.02). Subgroup analysis based on pathological lymph node status revealed that postoperative radiotherapy could improve OS regardless of pathological lymph node status (pathological lymph node positive patients: RR(5-year os-RCT) = 0.81, 95% CI: 0.70–0.93; RR(5-year os-NRCT) = 0.87, 95% CI: 0.80–0.94; Pathological lymph node negative patients: RR(3-year os-RCT) = 0.76, 95% CI: 0.59–0.96; RR(3-year os-NRCT) = 0.52, 95% CI: 0.30–0.89). No effect on distant recurrence rate was detected. Adverse effects induced by postoperative radiotherapy were comparatively modest and tolerable. CONCLUSION: Polled results yielded that postoperative radiotherapy was promising in improving OS and reducing the locoregional recurrence rate. More large-scale up-to-date RCTs are needed to further validate the use of postoperative radiotherapy in modern practice.