Background:Body mass index (BMI) has been associated with the risk of oesophageal cancer. But the influence of BMI on postoperative complication and prognosis has always been controversial.Methods:In total, 2031 consecutive patients who underwent oesophagectomy between 1998 and 2008 were classified according to Asian-specific BMI (kg m−2) cutoff values. The impact of BMI on overall survival (OS) was estimated using the Kaplan–Meier method and Cox proportional hazard models. We performed a meta-analysis to examine the association of BMI with OS and postoperative complication.Results:Patients with higher BMI had more postoperative complication (P=0.002), such as anastomotic leakage (P=0.016) and cardiovascular diseases (P<0.001), but less incidence of chylous leakage (P=0.010). Logistic regression analysis showed that BMI (P=0.005) was a confounding factor associated with postoperative complication. Multivariate analysis showed that overweight and obese patients had a more favourable survival than normal weight patients (HR (hazard ratio) = 0.80, 95% CI (confidence interval): 0.70–0.92, P=0.001). Subgroup analysis showed that the association with higher BMI and increased OS was observed in patients with oesophageal squamous cell carcinoma (ESCC) (P<0.001), oesophageal adenocarcinoma (EA) (P=0.034), never-smoking (P=0.035), ever-smoking (P=0.035), never alcohol consumption (P=0.005), weight loss (P=0.003) and advanced pathological stage (P<0.001). The meta-analysis further corroborated that higher BMI was associated with increased complication of anastomotic leakage (RR (risk ratio)=1.04, 95% CI: 1.02–1.06, P=0.001), wound infection (RR=1.03, 95% CI: 1.00–1.05, P=0.031) and cardiovascular diseases (RR=1.02, 95% CI: 1.00–1.05, P=0.039), but decreased incidence of chylous leakage (RR=0.98, 95% CI: 0.96–0.99, P<0.001). In addition, high BMI could significantly improved OS (HR=0.78, 95% CI: 0.71–0.85, P<0.001).Conclusion:Preoperative BMI was an independent prognostic factor for survival, and strongly associated with postoperative complications in oesophageal cancer.

The effect of adjuvant chemotherapy on survival of patients with thoracic esophageal squamous cell carcinomas is still controversial, and the subgroup of patients who will most likely benefit from the adjuvant chemotherapy on long-term survival has not yet been identified clearly. Studies published from 1995 to May 2012 were searched in Medline, Embase, PubMed, Cancerlit, the Cochrane Library, CNKI and major scientific meetings. Randomized controlled trials and nonrandomized studies comparing surgery plus adjuvant chemotherapy with surgery alone in patients with resectable thoracic esophageal squamous cell carcinomas were included. Eleven studies with a total of 2047 patients were identified, consisting of the adjuvant chemotherapy arm (n = 887) and surgery-alone arm (n = 1160). There was not statistically significant benefit on 3-year overall survival for adjuvant chemotherapy (risk ratio [RR] = 0.89, 95% confidence interval [CI], 0.72 to 1.09; P = 0.25). Adjuvant chemotherapy could significantly prolong the 1-year disease-free survival (DFS) (RR = 0.68, 95%CI, 0.51 to 0.89; P = 0.006), but not 3-year DFS (RR = 0.97, 95%CI, 0.73 to 1.29; P = 0.84). Further analysis showed that patients with stage III-IV diseases could benefit from adjuvant chemotherapy on 3-year overall survival (RR = 0.43, 95%CI, 0.31 to 0.61; P = 0.00001), but not in the case of patients with stageI-IIdiseases (RR = 1.12, 95%CI, 0.65 to 1.93; P = 0.68). Additionally, patients with positive lymph node could benefit on 5-year DFS from adjuvant chemotherapy (RR = 0.79, 95%CI, 0.64 to 0.99; P = 0.04). The modality treatment with adjuvant chemotherapy for patients with squamous cell carcinoma of thoracic esophagus might be determined according to pathological stage or the status of lymph node metastasis.