Leukemia in radiation-treated patients: cytogenetic studies in eight cases

Abnormal chromosomes have been found in various clinical settings and in cancer patients. Eight patients developed leukemia several years after the diagnosis and treatment of a primary malignant disease. All the patients were being treated with irradiation, and five of them also received chemotherapy, notably, alkylating agents. The type of leukemias and the interval between irradiation and leukemia parallel very well with those reported from the atomic bomb casualties. Chromosomal abnormalities were seen in all the patients. These abnormalities have been reported in irradiated normal persons without developed leukemias. These findings suggest that the development of clinical cancer or leukemia may depend, not only on the presence of abnormal cells, but also on other factors. Perhaps the environment that allowed the original cancer to develop in our patients is capable of allowing the radiation-induced abnormal cells to be expressed as clinical leukemia.