Cell type distribution in histologic specimens of primary lung cancer

A total of 1986 cases of primary lung cancer, observed in the Pathology Department of the University of Florence during 1971-1981, were analysed by age, sex, year of diagnosis, source of specimen, and cell type. Adenocarcinomas occurred more frequently in females and at younger ages and were diagnosed mainly from surgically obtained specimens. In contrast, squamous cell carcinomas developed more often in males and at older ages, and were chiefly diagnosed by bronchial biopsy. Over the 11-year period of study, a significant increase in the percentage of squamous cell carcinomas and a consequent decrease in the percentage of adenocarcinomas occurred both in females and in males, independent of changes in the specimen sources.