The action of antitumor agents: a double-edged sword?

Although cytotoxic immunosuppressive agents play an unquestionably useful role in treating many neoplastic and non-neoplastic disorders, there is accumulating evidence that the toxicity associated with their use is considerable. The therapeutic successes obtained with antitumor agents have led to increases in the life span of cancer patients, but have also provided the opportunity for this toxicity to become manifest. A search of the available literature was carried out, with emphasis on cases in which a malignancy developed in patients following chemotherapy for either neoplastic or non-neoplastic (e.g., renal transplantation, psoriasis) conditions; particular focus was given to the incidence of acute myelogenous leukemia in various groups of Hodgkin's disease and multiple myeloma patients. That patients with nonmalignant conditions treated with cytotoxic immunosuppressive agents are also at increased risk of developing a malignancy raises the possibility that these agents may have oncogenic potential. Therefore, one may be faced with the paradox that the patients benefiting most from chemotherapy may be at highest risk of suffering its consequences.