PURPOSE:A low DLCO is a predictor of short term operative morbidity and mortality. We examined the late prognostic significance of DLCO and FEV1 in patients who underwent surgical resection of lung cancer.
METHODS:From 1997 to 2004, 546 patients were prospectively entered into a database prior to surgical resection for lung cancer. 462 patients had successful complete resection of their lung cancer and full pulmonary function testing including DLCO performed. Mean follow up was 64.8 months (range: 0 to 158 months). Pooled t-tests, Fisher’s exact tests, and Cox proportional hazards regression analysis were used to test for significance.
RESULTS:Postoperative 90 day mortality was 2.6% (12/462). Of the remaining 450 patients, 182 patients are alive, 130 have died of cancer, and 138 have died of other causes without recurrent cancer. Mean DLCO values were 69.4%, 66.8% and 53.9%, respectively. Mean FEV1 values were 81.3%, 78.1%, and 71.5%, respectively. Mean DLCOs and FEV1s between patients who died of cancer vs. other causes were significantly different (p < .0001 and p=0.0157). Cause specific survival was analyzed for both DLCO and FEV1 simultaneously in a multivariate analysis, DLCO had a very strong significant effect on survival from other causes (HR 0.966, p<0.0001) when adjusted for FEV1. However, when adjusted by DLCO, FEV1 had no significant effect. Lower DLCO best predicted decreased survival from causes other than cancer within stage I lung cancers (stage IA HR 0.953, p<0.0001; stage IB HR 0.968, p<0.0001). Independently, a DLCO less than 40% was found to be the optimal cut-off point in best differentiating survival from causes other than cancer (p < .0001) [Figure 1].
CONCLUSION:DLCO is a significant prognostic factor for long term survival after lung cancer surgery. Declining DLCO values predict a higher risk of late non-cancer related death.
CLINICAL IMPLICATIONS:These results warrant further investigation and may influence future surgical planning in patients with lung cancers and impaired pulmonary diffusion capacity.
DISCLOSURE:Michael Liptay, No Financial Disclosure Information; No Product/Research Disclosure Information