Is postoperative chemotherapy necessary for resected esophageal carcinoma after neoadjuvant chemoradiotherapy? A systematic review and meta-analysis

Background Both neoadjuvant chemoradiotherapy (NCRT) and postoperative chemotherapy (PT) are crucial treatments for esophageal carcinoma (EC). However, it is not clear whether PT is required for EC treatment after NCRT. This systematic review and meta-analysis aimed at clarifying the necessity of PT for resected EC after NCRT.Methods We searched PubMed, Embase, and The Cochrane Library databases for relevant studies published up to March 2020, that have compared PT and non-PT for resected EC after NCRT (NCRT + PT vs. NCRT). The primary outcome of this study was overall survival (OS). Hazard risk ratio (HR) and 95% confidence interval (CI) were calculated. Subgroup and sensitivity analyses were employed to explore heterogeneity, and the random effect model was used to merge the meta-analysis data, regardless of whether the heterogeneity was large or small.Results This study included seven retrospective cohorts, with more than 10720 patients. Most of the patients had esophageal adenocarcinomas. The Meta-analysis showed that NCRT followed by PT increased the patient OS (HR = 0.79, 95% CI 0.74–0.85, P < 0.001). However, further subgroup analysis showed that NCRT + PT might not improve the OS of resected EC patients with a negative lymph node status (HR = 0.82, 95% CI 0.67–1.01, P = 0.124). Further, we showed that NCRT with PT improved the survival of EC patients with a positive lymph node status who underwent resection (HR = 0.78, 95% CI 0.70–0.86, P < 0.001).Conclusion PT may improve the survival of lymph node-positive EC patients previously treated by NCRT. This conclusion may be more applicable to EAC patients treated with NCRT at the ypN + stage.