Clinical Discussion of the Management of Anaplastic Oligodendroglioma/Oligoastrocytoma (Both Codeleted and Nondeleted)

Anaplastic oligodendroglioma (AO) and anaplastic oligoastrocytoma (AOA) are uncommon malignant tumors occurring in adults, but have garnered attention because of a high rate of response to chemotherapy in early studies. However, no clinical trial had demonstrated benefit with the addition of chemotherapy to radiotherapy alone until the long-term results of RTOG 9402 and EORTC 26951. These studies revealed prolonged survival in patients with anaplastic gliomas harboring the 1p/19q codeletion when treated with PCV (procarbazine, lomustine, and vincristine) and radiation therapy compared with radiation alone. These studies validated the use of 1p/19q codeletion status as a predictive biomarker in these tumors. Additional molecular characterization of these tumors may provide additional insight into treatment decisions, although these characterizations have yet to be fully elucidated. Even with the strength of the data advocating the use of combination therapy (PCV and radiotherapy), the incorporation of newer, less-toxic drugs such as temozolomide into many practices in the past decade raises important questions regarding the optimal chemotherapy regimen. Unfortunately, additional definitive phase III trials will take several years to answer remaining questions. Regardless, it is clear that patients with 1p/19q codeleted AO or AOA who can tolerate chemotherapy should not receive radiotherapy alone.