Treatment-related myelodysplasia in patients with primary brain tumors.

Treatment-related myelodysplastic syndrome (t-MDS) and treatment-related acute myelogenous leukemia (t-AML) represent rare secondary events in patients with primary tumors of the nervous system and predominantly affect those treated with alkylating agents or topoisomerase II inhibitors. Temozolomide has become the standard chemotherapeutic agent for malignant gliomas. The emergence of this alkylating agent with little acute toxicity or cumulative myelosuppression has led to off-label protracted chemotherapy for many patients with malignant and even low-grade infiltrative gliomas, raising concern for increased risk of t-MDS/t-AML in the few long-term survivors. On the basis of an extensive literature search, we provide a discussion of epidemiology, pathogenesis, clinical presentation, diagnosis, and therapy of these disorders. t-MDS/t-AML remain rare complications of chemotherapy in patients with primary brain tumors, and the vast majority of patients die of their primary neoplasm. Prospective randomized studies with long-term follow-up are required to accurately assess the risk of t-MDS/t-AML; however, unless survival in the most common gliomas substantially increases, t-MDS/t-AML incidence will likely remain low in this patient population.