Therapy-related erythroleukemia caused by the administration of UFT and mitomycin C in a patient with colon cancer.

A 54-year-old man with colon cancer underwent hemicolectomy. He received postoperative adjuvant chemotherapy with UFT (tegafur/uracil at a 1 : 4 molar ratio) and mitomycin C (MMC) for 3 years. Three years and 4 months after the start of chemotherapy, pancytopenia was noted. Bone marrow aspiration smear demonstrated an increased number of immature erythroblasts, including megaloblasts and myeloblasts. Chromosomal analysis demonstrated structural and numerical abnormalities of 5, 7, 15, and 17. Therapy-related erythroleukemia, acute myeloid leukemia (AML), M6, was diagnosed. The disease progressed after 5 months, and the patient was received chemotherapy with cytosine arabinoside, aclacinomycin, and granulocyte colony-stimulating factor (CAG), and showed a partial hematological response. Careful monitoring for the generation of therapy-related leukemia is needed when UFT and MMC are used for postoperative adjuvant chemotherapy for colorectal cancer.