Does obesity affect outcomes in patients undergoing esophagectomy for cancer? A meta-analysis

Background: The incidence of esophageal carcinoma and the global prevalence of obesity are both increasing. As a result, there is an increased number of esophagectomies being performed on obese patients. The identification of specific complications in obese patients undergoing esophagectomy may allow improved risk assessment and postoperative management to reduce morbidity and mortality. This meta-analysis aimed to determine whether obese patients are at increased risk of postoperative complications, mortality, and compromised survival compared to non-obese patients following esophageal resection. Methods: A Medline, Embase, Ovid, and Cochrane database search was performed on all articles between January 1980 and January 2012 comparing post-esophagectomy outcomes between obese and non-obese patients. This study was conducted in accordance with the recommendations of the Cochrane Collaboration and the Quality of Reporting of Meta-Analyses guidelines. Results: There was no significant difference between obese and non-obese patients with respect to extent of tumor resection, cardiorespiratory complications, anastomotic leakage, reoperation rates, wound infection, or postoperative mortality. Meta-regression analysis showed that diabetes in obese patients was associated with a significant impact on the risk of anastomotic leakage (coefficient = -7.94 [-15.24-0.65, P = 0.03) and atrial fibrillation (coefficient = -6.94 [-12.79-1.10], P = 0.02). Overall, obese patients had significantly better long-term survival than non-obese patients (Hazard Ratio = 0.78 [0.64-0.96], P = 0.02). Conclusions: In patients who are eligible for surgery, obesity alone does not increase risk of postoperative complications or mortality and should not be an independent contraindication for esophagectomy. However, the presence of diabetes mellitus in conjunction with obesity may be associated with increased risk of anastomotic leakage and atrial fibrillation. Because of the adverse physiological remodeling in obesity, surgeons should maintain a low threshold for the investigation and management of complications and ensure meticulous management of co-morbidities. Obesity may also improve longterm postoperative survival after esophageal surgery, although further studies with higher levels of evidence are necessary to fully determine any advantageous effects of obesity following oncological esophageal surgery.