Prognostic value of chronic obstructive pulmonary disease in 2994 cases of lung cancer

OBJECTIVE: Given the frequent association between chronic obstructive pulmonary disease (COPD) and lung cancer (LC), the objective of this paper is to analyse the prognosis of this comorbidity. METHODS: Multicenter prospective study compiling 2994 consecutive cases of surgically treated LC (1993-1997), the population with non-small cell lung cancer and complete resection was selected for the prognostic study of COPD. COPD is defined when the FEV1/FVC is <0.7 (n=1370; 46%). Overall and conditional survivals (survival likelihood when alive at 2, 3 or 5 years after treatment) as well as the degree of severity (FEV1% percentiles) were calculated to establish prognosis. RESULTS: Although the overall survival is similar whether or not COPD is present (Log-rank: 0.34), the conditional survival analysis is different in every stage at 60 months (Log-rank: 0.02) and different in stage pI at 24-36 months (Log-rank: 0.04). In LC (stage pI) with COPD, the presence of a worst pulmonary function (last FEV1% percentile vs first FEV1% percentile) is a bad prognostic factor (Log-rank: 0.002). CONCLUSIONS: The analysis of conditional survival at 24 months shows that COPD can be considered as a prognostic factor and that there is a clear relationship between the severity of the condition (FEV1%) and survival.