Second primary cancers following treatment of Hodgkin's disease.

A cohort study designed to evaluate the carcinogenicity of treatment for Hodgkin's disease (HD) was conducted. This report describes 2,591 patients with HD diagnosed in 1940-75 and presents an analysis of follow-up findings through 1978. Seventy-four second primary cancers (excluding basal cell and squamous cell cancers of the skin and in situ carcinomas of the cervix uteri) were observed 1 year or more after diagnosis of HD, including 21 leukemias. Twenty leukemias occurred after chemotherapy. The relative risk (RR) of leukemia after intensive chemotherapy with or without radiotherapy was 136 relative to general population incidence rates. In the subgroup with both intensive chemotherapy and intensive radiotherapy, the RR of leukemia was 125. Both RR estimates differed significantly from unity. The RR of cancers other than leukemia 10 years or more after intensive radiotherapy relative to no intensive therapy was 19.5 (95% confidence limits: 4.8-80).