Elective nodal irradiation versus involved-field irradiation in patients with esophageal cancer receiving neoadjuvant chemoradiotherapy: a network meta-analysis

BACKGROUND: To assess the comparative efficacy and safety of elective nodal irradiation (ENI) and involved-field irradiation (IFI) in patients with esophageal cancer (EC) receiving neoadjuvant chemoradiotherapy plus surgery (nCRTS). MATERIAL AND METHODS: PubMed, Embase, Cochrane Library, Web of Science and major meetings were searched for randomized controlled trials (RCTs) that compared at least two of the following treatment regimens: nCRTS, neoadjuvant chemotherapy plus surgery (nCTS), and surgery (S) alone. Overall survival (OS) was the primary outcomes of interest, reported as hazard ratio (HR) and 95% confidence intervals (CIs). A Bayesian network meta-analysis was performed to compare all regimens simultaneously. RESULTS: Twenty-nine RCTs with a total of 5212 patients were included in the meta-analysis. Both nCRTS adopting ENI (nCRTS-ENI) (HR = 0.63, 95% CI: 0.48–0.83) and nCRTS adopting IFI (nCRTS-IFI) (HR = 0.75, 95% CI: 0.66–0.86) significantly improved OS compared to S alone. No significant differences in OS, locoregional recurrence, distant metastases, R0 resection and postoperative mortality were observed between nCRTS-ENI and nCRTS-IFI. In subgroup analyses, nCRTS-IFI showed a significant OS advantage over nCTS (HR = 0.78, 95% CI: 0.63–0.96) and S alone (HR = 0.50, 95% CI: 0.38–0.68) for esophagus squamous cell carcinoma (ESCC), but nCRTS-ENI did not; nCRTS-ENI using three-dimensional radiotherapy (3D-RT) resulted in an improved OS compared to that with 2D-RT (HR = 0.58, 95% CI: 0.34–0.99). Based on treatment ranking in term of OS, nCRTS-IFI (0.90) and nCRTS-ENI (0.96) was ranked the most effective treatment for ESCC and esophagus adenocarcinoma (EAC), respectively. CONCLUSION: Either adopting ENI or IFI, nCRTS is likely to be the optimal treatment for resectable EC, and nCRTS-IFI and nCRTS-ENI seem to be more effective for patients with ESCC and EAC, respectively. Future head to head comparison trials are needed to confirm these findings.