The prognosis of lung cancer originating as a round lesion. Data from the Philadelphia pulmonary neoplasm research project.

A population of 6,027 men 45 or more years of age was screened every 6 months for 10 years with chest photofluorograms and questionnaires regarding symptoms. Although volunteers, they were similar to older men in the general population with respect to age, race, and smoking habits. Of 121 men who developed lung cancer after the beginning of observation, 48 had neoplasms appearing as round lesions at the time of radiographic detection. Only 8 per cent of the 48 men survived 5 years or more, a rate identical to that of men in whom cancer first appeared in some other form. There was an inverse relationship between initial size of the cancer and survival. Two thirds of the tumors were squamous cell carcinomas. Comparison with the literature suggests that selection accounts for the favorable prognosis of round lung cancers in hospital-based series.