Systematic review of prognostic roles of body mass index for patients undergoing lung cancer surgery: does the 'obesity paradox' really exist?
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational cohort studies
PubMed 28040677 · doi:10.1093/ejcts/ezw386
What was done
A systematic review and meta-analysis of literature retrieved from PubMed was conducted to evaluate the prognostic value of body mass index (BMI) in patients undergoing lung cancer surgery. The authors pooled odds ratios (OR) for in-hospital morbidity and mortality, as well as hazard ratios (HR) for long-term survival, across 25 observational studies encompassing 78,143 patients.
What was found
Obesity was associated with significantly decreased overall morbidity (OR: 0.84; 95% CI: 0.73–0.98; P = 0.025) and in-hospital mortality (OR: 0.78; 95% CI: 0.63–0.98; P = 0.031). For long-term outcomes, higher BMI and obesity significantly predicted favorable survival (HR for obesity: 0.69; 95% CI: 0.56–0.86; P = 0.001), though increased BMI in general showed no significant benefit specifically for in-hospital morbidity. No publication bias was detected.
Why it matters
These findings suggest that the "obesity paradox" applies to thoracic surgery, where elevated BMI is associated with lower perioperative mortality and superior long-term survival after lung cancer resection.
Limits
The review relies entirely on observational studies, which carry inherent risks of unmeasured confounding and reverse causality (such as cancer-related weight loss and cachexia in sicker patients). Only PubMed was searched, risking omission of eligible studies from other databases, and detailed clinical covariates like smoking history, cancer stage, and body composition were not accounted for in the abstract.
Cited by
- supports In lung cancer, patients with obesity/higher BMI have been observed in studies to experience longer survival than normal-weight patients.