Smoking and survival from lung cancer

The role of smoking in the etiology of lung cancer is well known but less is known about whether smoking also affects the pathological process. In the present analysis 290 lung cancer patients were divided into three equal-sized groups according to lifetime cigarette consumption (heavy, moderate, light/none). The age of the patient, histology, TNM and S-phase fraction of the tumor were confirmed as prognostic factors. The association between smoking and these factors was evaluated. There was a significant difference in histological type of tumor; adenocarcinomas were more common than other types among light smokers. Tumor size, nodal status and occurrence of distant metastases did not differ significantly between the smoking groups. Heavy smokers had a greater frequency of aneuploid tumors and the S-phase fraction was higher among these patients but neither of these differences was statistically significant. Survival analysis indicated no statistically significant association between survival and lifetime total cigarette consumption. Apart from histological type, smoking is not materially associated with clinical and biological prognostic factors, nor does smoking materially affect the survival of lung cancer patients. Our study material was relatively small and therefore not of sufficient power to detect small effects.