Prognostic factors for surgically treated lung adenocarcinoma patients, with special reference to smoking habit

Prognostic factors for lung adenocarcinoma patients who had been treated surgically at the Center for Adult Diseases, Osaka, in 1978-87 (N = 267) were analyzed in terms of year of operation, sex, age at operation, postsurgical stage, grade of differentiation, and smoking habit. Survival was improved for later year of operation (1983-87), younger age at operation, stage I or II, well or moderately differentiated adenocarcinoma, and nonsmoking status in univariate analysis. A proportional hazards model including the above variables showed that stage III and stage IV patients had 4.06 and 8.81 times higher risk of death compared to stage I and II patients. Poorly differentiated adenocarcinoma showed 2.01 times higher risk of death than well or moderately differentiated adenocarcinoma. Earlier year of operation and female status showed 1.70 and 1.82 times higher risk of death, respectively, as compared to each reference group. All these hazard ratios showed statistical significance. Current smokers who smoked 1,000 or more on the cigarette index showed 2.38 times higher risk of death than nonsmokers with statistical significance. This indicates that smoking is another independent prognostic factor for patients who undergo operations for adenocarcinoma of the lung.