Second primary cancer following treatment for cervical cancer.

A follow-up study of 7535 women in Ontario was carried out to assess the occurrence of second primary cancers following the treatment of invasive carcinoma of the cervix between 1960 and 1975. The study was part of a larger international investigation of late radiation effects in patients with cervical cancer. Data were collected on the date and the type of treatment for cervical cancer and on the occurrence of second primary cancers diagnosed before 1980. Observed and expected numbers of second primary cancers, the latter determined according to Ontario incidence rates, were compared for individual sites and for all sites combined. There were significantly more primary cancers of the lung than expected (64 v. 15.52) but significantly fewer second primary cancers of the breast (56 v. 105.01) and colon (27 v. 43.31). Overall, there were significantly fewer (p less than 0.05) observed second primary cancers than expected (280 v. 394). Although the median follow-up period was less than 10 years there was no marked evidence of an excess of radiation-induced second primary cancers.