The long-term survival of an incident lung cancer population was evaluated in relation to clinical stage, treatment modalities and other prognostic factors. The survey was carried out among the residents in the Local Sanitary Unit of Saronno, a highly industrialized area of northern Italy, where all the lung cancer cases diagnosed during the years 1976-79 had been identified and clinically studied. The overall survival of the 222 cases included in the analysis was 32% at 1 year, 10% at 3 years and 5% at 5 years; median survival was 7 months. A significantly better prognosis was associated with surgical resection (32% at 5 years; median, 42 mo), clinical stage I (16% at 5 years; median, 15 mo), and squamous cell carcinoma (13% at 5 years; median, 11 mo). Other factors such as age, sex, social class or cancer symptoms did not affect survival when treatment was taken into account. Our data show that surgical resection is the major determinant of survival, and suggest that sub-optimal access to curative treatment, particularly in patients aged 60 to 75 with limited disease, might have compromised the overall survival.