Second malignant neoplasms associated with immunosuppressive medications.

Previous studies have shown that immunosuppressive therapy permits the growth and spread of inadvertently transplanted malignant cells in man, and, in addition, is associated with a 5 to 6% incidence of de novo cancers in organ homograft recipients who were apparently free of cancer before and at the time of transplantation. In the present report two further groups of patients were studied. There was a 4% incidence of new tumors in 101 organ homograft recipient- who had had pre-existing cancers. The immunosuppressive effects of cancer chemotherapeutic agents may have been responsible for the development of 166 new malignancies in 160 patients who received treatment for 161 neoplasms. This does not contraindicate the use of chemotherapy in patients with advanced or widespread neoplasms, as the occasional development of new malignancies is far outweighed by the many months or years of control of the original tumors.