Long-term treatment with temozolomide in malignant glioma

Six months of maintenance temozolomide (TMZ) following concurrent TMZ chemotherapy and radiation therapy has become the standard of care in the treatment of glioblastoma. In addition, TMZ has also been used to treat other forms of glioma although less evidence of efficacy exists. TMZ administration longer than 6 months is common in clinical practice, but it is unusual for the drug to be administered longer than 1 to 2 years. We report five patients who received long-term treatment with TMZ chemotherapy at normal dosing levels. One of these patients was diagnosed with glioblastoma, two with anaplastic astrocytoma, one with gliosarcoma, and one with oligo-astrocytoma. The length of treatment in our group of patients ranged from 45 to 85 cycles of TMZ. Common Terminology Criteria for Adverse Events (CTCAE) developed by The National Cancer Institute was used to classify toxicity. Two patients experienced no toxicity per CTCAE guidelines. One patient experienced grade I thrombocytopenia, one developed grade I leukopenia, and one experienced both grade I thrombocytopenia and grade I nausea, all which resolved with either withholding TMZ for 1 month or supportive treatment. Our report provides evidence that long-term TMZ chemotherapy is a therapeutic option when appropriately monitored.