Therapy-related myelodysplastic syndrome in children with medulloblastoma following MOPP chemotherapy.

Between 1978 and 1988, 20 children with medulloblastoma (MB) of the brain were treated postoperatively with MOPP (nitrogen mustard, vincristine, prednisone, and procarbazine). All but one received post-operative radiation prior to MOPP. Eight of 20 patients remained in continuous complete remission from MB, two of whom eventually developed myelodysplastic syndrome (MDS). Following resection of MB at age 12 months, one patient was treated with 24 courses of MOPP over 2 years without radiation therapy. She developed pancytopenia, and MDS was diagnosed 19 months after the completion of MOPP. Analysis of unstimulated bone marrow (BM) chromosomes showed structural abnormalities involving chromosomes 7, 10, 17, and 21. Eight months later, MDS evolved into acute myeloid leukemia. The second patient was diagnosed with MB at age 7 years and received postoperative craniospinal radiation followed by 12 courses of MOPP over one year. Five months after completion of MOPP, she developed MDS with monosomy 7 on chromosome analysis of bone marrow cells. Therapy-related MDS may be a complication of MOPP chemotherapy for MB in young children.