Epidemiologic study of carcinoma in situ of the cervix.

From 1950 to 1979, 1,248 cases of cancer in situ were treated in the Department of Gynecology, Cancer Institute Hospital, Tokyo. Detailed data were obtained from 585 of the patients by interview. Many patients had had their first sexual experience at an early age. Many had had more than two sexual partners, and there was a large discrepancy between the age at first sexual intercourse and at first marriage. The above factors seem to be related to the development of cancer in situ.