Secondary neoplasms as a consequence of transplantation and cancer therapy.

A complication of various therapies is an increased incidence of cancers. We present data on 3117 types of cancer that developed in 2915 immunosuppressed organ-transplant recipients. The predominant tumors are lymphomas, skin and lip carcinomas, vulvar and perineal carcinomas, in situ uterine-cervical carcinomas, and Kaposi's sarcoma (KS). Tumors appear a relatively short time after transplantation, the earliest being KS at an average of 23 months and the latest vulvar and perineal cancers presenting an average of 98 months after transplantation. Cytotoxic drugs given to cancer patients may cause secondary neoplasms either by a direct carcinogenic effect or, indirectly, through depression of immunity. The most common secondary malignancies are leukemias, lymphomas, and bladder carcinomas. Ionizing radiation causes cancer, either by a direct carcinogenic effect on cells in the radiation field, or indirectly by depressing immunity. The most common malignancies are leukemias and bone sarcomas.