UCSF

Secondary malignancies due to alkylating agents or topoisomerase II inhibitors are a concern in patients treated for primary brain tumors of the nervous system. Myelosuppression is the dose-limiting toxic effect of the alkylating agent temozolomide; reversible hematologic toxicity consisting mainly of thrombocytopenia is reported to occur in 7% of patients treated with concomitant radiotherapy and temozolomide and 14% with adjuvant temozolomide.1 However, the incidence of secondary malignancies and nonreversible hematologic disorders, such as myelodysplastic syndrome, are a rare complication of temozolomide.2