title: A high body mass index in esophageal cancer patients is not associated with adverse outcomes following esophagectomy.
abstract: OBJECTIVE
  There is no consensus about the impact of a high BMI on postoperative morbidity and survival after esophagectomy. The aim of this study was to determine the influence of a high BMI on postoperative complications and survival in a large cohort of esophageal cancer patients.
  
  
  METHODS
  From January 2006 to December 2012, 1,342 consecutive esophageal cancer patients who underwent esophagectomy were included in this study. Patients were divided into three groups: 950 patients were classified as normal BMI (BMI 18.5-24.9 kg/m(2)), 279 were classified as high BMI (BMI ≥ 25 kg/m(2)), and 113 as low BMI (BMI < 18.5 kg/m(2)). Multivariate logistic regression models were used to identify confounding factors associated with postoperative complications. The impact of BMI on overall survival (OS) was estimated by the Kaplan-Meier method and Cox proportional hazard models.
  
  
  RESULTS
  The predominance of pathological type was esophageal squamous cell carcinoma (n = 1,280, 95.4 %). Overall morbidity, mortality, and hospital stay did not differ among groups. The incidence of pneumonia was higher in patients with high BMI compared with those with normal BMI (14.7 vs. 9.9 %, P = 0.025). However, chylothorax was less frequent in high-BMI group (0.4 % in high-BMI group, 3.1 % in normal group, and 3.5 % in low group, P = 0.011). Logistic regression analysis revealed high BMI was independently associated with decreased incidence of chylothorax [HR 0.86; 95 % confidence interval 0.76-0.97]. Overweight and obese patients had significantly better overall survival than underweight patients (median OS 55.6 vs. 32.5 months, P = 0.013), while the pathological stage was significantly higher in underweight patients (P = 0.001). In multivariate analysis, T status, N status, differentiation grade, and tumor length were identified as independent prognostic factors.
  
  
  CONCLUSIONS
  A high BMI is not associated with increased overall morbidity following esophagectomy; moreover, it is associated with decreased incidence of chylothorax. The better overall survival in patients with high BMI compared with those with low BMI might be due to a relatively low pathological stage. A high BMI should therefore not be a relative contraindication for esophagectomy.
authors.affiliation: Department of Thoracic Surgery, Fudan University Shanghai Cancer Center, 270 Dong An Road, Shanghai, 200032, China.
authors.forename: Longsheng
authors.initials: L
authors.lastname: Miao
authors.forename: Haiquan
authors.initials: H
authors.lastname: Chen
authors.forename: Jiaqing
authors.initials: J
authors.lastname: Xiang
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002294:Carcinoma, Squamous Cell / Q000150:complications / Q000556:secondary / Q000601:surgery*; D004938:Esophageal Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery*; D000077277:Esophageal Squamous Cell Carcinoma; D016629:Esophagectomy / Q000009:adverse effects; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D011183:Postoperative Complications / Q000453:epidemiology; D016016:Proportional Hazards Models; D016896:Treatment Outcome