Leukemia and other cancers after radiotherapy and chemotherapy for Hodgkin's disease.

A cohort study designed to evaluate the carcinogenicity of treatment for Hodgkin's disease (HD) was begun in 1976. This report describes 1,553 patients diagnosed with HD in 1940-75 and presents an analysis of follow-up findings through 1976. Twenty-seven cancers (excluding basal cell and squamous cell carcinomas of skin, trichoepitheliomas, and in situ carcinomas of cervix uteri) were observed 1 year or more after diagnosis of HD, including 6 leukemias. The relative risk (RR) of leukemia in patients treated with intensive chemotherapy with or without radiotherapy relative to general population incidence rates was 140 (95% confidence limits: 50,300). In the subgroup treated with both intensive radiotherapy and intensive chemotherapy, the RR of leukemia was 270 (95% confidence limits: 56,800). No leukemia occurred after treatment with intensive radiotherapy without chemotherapy. For cancers other than leukemia and for non-HD lymphomas, RR was generally not significantly different from the null value one.