Chemotherapy of Oligoastrocytomas

Oligoastrocytomas are tumors consisting of areas of cells with the morphologic characteristics of oligodendroglioma intermingled with areas where the morphology of the cells is astrocytic. In most, the cells are diffusely mixed. Tumors with separate areas of oligodendroglial and astrocytic cells are not common. Oligoastrocytomas have an incidence between 2 and 10% of all gliomas. At present, there seems to be two main categories of oligoastrocytoma. Those that have 1p and 19q deletions and those with TP53 mutations. The former, typical of pure oligodendroglioma, suggest oligodendroglial lineage. TP53 mutations are typical of astrocytomas, suggesting that those oligoastrocytomas may be derived from astrocytic precursor cells. This chapter focuses on studies in which there has been an attempt to analyze chemotherapy of oligoastrocytomas separately from oligodendrogliomas. It reviews several studies on use of various chemotherapeutic agents including procarbazine, lomustine [1,(2-chloroethyl)-3-cyclohexyl-1-nitrosurea, CCNU], and vincristine (PCV), temozolomide (TMZ), and other chemotherapy regimens in anaplastic and low-grade oligoastrocytomas.