SECONDARY MALIGNANCIES FOLLOWING CANCER-CHEMOTHERAPY

Many agents used in cancer chemotherapy are known carcinogens. However , few secondary malignancies have been definitely linked to chemothera py, since studies on this problem are complicated by methodological pr oblems. A causal relationship has been established between alkylating agents and leukaemia and between cyclophosphamide and bladder cancer. The risk of leukaemia peaks at 5-10 years after beginning of chemother apy and declines steadily after its end. The interaction between chemo therapy and radiotherapy has not been fully clarified, nor has the leu kaemogenic potency of individual drugs, although combinations without nitrogen mustard seem to entail a lower risk. Other tumours reported a t increased incidence, in particular among Hodgkin's disease patients, for whom a carcinogenic effect of chemotherapy seems plausible, are n on-Hodgkin's lymphoma and lung cancer. Other secondary solid tumors ha ve also been reported, but for none of them an independent effect of c hemotherapy has been demonstrated.