Objectives: Predictors of long-term survival for patients with lung cancer assist in individualizing treatment recommendations. Diffusing capacity (DLCO) is a predictor of complications after resection for lung cancer. We sought to determine whether DLCO is also prognostic for long-term survival after lung resection for cancer.
Methods: We assessed survival among patients in our prospective database who underwent lung resection for cancer between 1980-2006. Potential prognostic factors for all-cause mortality were evaluated by computing average annual hazard rates, and variables significantly associated with survival were included in multivariable Cox modelling. Multiple imputation was used to address missing values.
Results: Among 854 unique patients, there were 587 deaths. The median follow-up time from surgery was 9.6 years. Predictors of survival included age, stage, performance status, body mass index, history of myocardial infarction, renal function and DLCO. On univariate analysis, the hazard ratio increased incrementally compared with those with a DLCO of ≥ 80% (70-79%, 1.12; 60-69%, 1.29; <60%, 1.35). On multivariable analysis, DLCO was an independent predictor of long-term survival for all patients (corrected for all other important covariates; HR 1.04 per 10-point decrement; 95% CI 1.00-1.08; P = 0.05). Its prognostic ability for long-term survival was above and beyond its influence on operative mortality.
Conclusions: DLCO is an independent and clinically important determinant of long-term survival after major lung resection for cancer, a finding that is not generally known. Knowledge of this may help improve selection of patients for lung resection and may help tailor the extent of resection, when possible, in order to appropriately balance operative risk with long-term outcomes.