The overall age-standardized incidence is 3.5 per million person years with a peak incidence of 8 per million population in the 75 to 79 year age group.
Anaplastic astrocytomas fall under the category of high grade gliomas (WHO grade III-IV), which are pathologically undifferentiated gliomas that carry a poor clinical prognosis. Unlike glioblastomas(WHO grade IV), anaplastic astrocytomas lack vascular proliferation and necrosis on pathologic evaluation.
Compared to grade II tumors, anaplastic astrocytomas are more cellular, demonstrate more atypia, and mitoses are seen.
Anaplastic Astrocytoma: The first step in treatment of anaplastic astrocytoma is surgery. Radiation is then used to treat the remaining tumor. Chemotherapy may be recommended immediately after radiation or when and if the tumor recurs.
Temozolomide (TMZ) for malignant gliomas is traditionally dosed in 5 out of a 28-day cycle, however alternative regimens exist, including dose-dense. Continuous daily dosing is available, but the acceptable dose and duration of therapy is unknown.
Zhou et al. document a 40-year-old male with recurrent anaplastic astrocytoma, IDH mutant and MGMT promotor methylation negative, who has well-tolerated continuous daily TMZ for 20 months at 100 mg per day for nearly the length of this period. A trial at 80 mg per day demonstrated disease progression with response upon return to 100 mg per day. Prior to the daily TMZ, the patient underwent three surgical resections, radiation therapy with concurrent TMZ according to the EORTC NCIC protocol, and subsequently bevacizumab in combination with use of the Optune device. Long-term survival of patients with recurrent malignant gliomas is uncommon, and currently no standard treatment strategies exist for these patients. We present this case to demonstrate the tolerability and dose dependency of prolonged daily TMZ dosing as a therapeutic option for recurrent anaplastic astrocytomas 1).