ABSTRACT
@#To investigate the effect of the interval between neoadjuvant chemoradiotherapy (nCRT) and surgery on the clinical outcome of esophageal cancer. Methods PubMed and EMbase databases from inception to March 2018 were retrieved by computer. A random-effect model was used for all meta-analyses irrespective of heterogeneity. The meta-analysis was performed by RevMan5.3 software. The primary outcomes were operative mortality, incidence of anastomotic leakage, and overall survival; secondary outcomes were pathologic complete remission rate, R0 resection rate, and positive resection margin rate. Results A total of 17 studies with 18 173 patients were included. Among them, 13 were original studies with 2 950 patients, and 4 were database-based studies with a total of 15 223 patients. The results showed a significant positive correlation between the interval and operative mortality (Spearman coefficient=0.360, P=0.027). Dose-response meta-analysis revealed that there was a relatively better time window for surgery after nCRT. Further analysis for primary outcomes at different time cut-offs found the following results: (1) when the time cut-off point within 30-70 days, the shorter interval was associated with a reduced operative mortality (7-8 weeks: RR=0.67, 95% CI 0.55-0.81, P<0.05; 30-46 days: RR=0.63, 95%CI 0.47-0.85, P<0.05; 60-70 days: RR=0.64, 95%CI 0.48-0.85, P<0.05); (2) when the time cut-off point within 30-46 days, the shorter interval correlated with a reduced incidence of anastomotic leakage (RR=0.39, 95%CI 0.21-0.72, P<0.05); when the time cut-off point within 7-8 weeks, the shorter interval could achieve a critical-level effect of reducing the incidence of anastomotic leakage (RR=0.73, 95%CI 0.52-1.03, P>0.05); (3) when the time cut-off point within 7-8 weeks, increased interval significantly was associated with the poor overall survival (HR=1.17, 95% CI 1.00-1.36, P<0.05). Secondary outcomes found that the shorter interval could significantly reduce the positive resection margin rate (RR=0.53, 95% CI 0.38-0.75, P<0.05) when time cut-off point within 56-60 days. Conclusion Shortening the interval between nCRT and surgery can reduce the operative mortality, the incidence of anastomotic leakage, long-term mortality risk, and positive resection margin rate. It is recommended that surgery should be performed as soon as possible after the patient's physical recovery, preferably no more than 7-8 weeks, which supports the current study recommendation (within 3-8 weeks after nCRT).