Anaplastic oligodendroglial
tumors have gained increasing interest with the emerging role of molecular markers and systemic
chemotherapy during the past years. The long-term results of two landmark trials, RTOG 9402 and EORTC 26961, have resulted in a reconsideration of the appropriate therapeutic approaches for patients with these
tumors. Both trials indicate that patients whose
tumors harbor a 1p/19q co-deletion benefit particularly from the addition of
procarbazine/
lomustine (
CCNU)/
vincristine (PCV)
chemotherapy to
radiation therapy (RT). The median survival of patients with co-deleted
tumors treated within the RTOG trial with PCV before irradiation was 14.7 years compared with 7.3 years of patients who received RT alone. Median overall survival has not been reached in the RT plus PCV arm of the EORTC trial, but a similar difference can be anticipated after a follow-up of more than 12 years. In contrast, no such benefit was observed for patients with
tumors lacking 1p/19q co-deletion. Outside clinical trials, patients with anaplastic oligodendroglial
tumors, and 1p/19q co-deletion therefore should be offered a combined treatment modality regimen, including radio- and
chemotherapy. PCV, however, is associated with significant hematological toxicity and also nonhematological side effects, which probably translate into reduced quality of life for long-term survivors. Therefore, it might be warranted to replace PCV by
temozolomide, which displays a more favorable side effect profile. Data from the NOA-04 study suggest that PCV and
temozolomide have similar effects. However, long-term data on the benefit from
temozolomide are lacking, making a definite answer on the equivalence of
temozolomide and PCV in
anaplastic oligodendroglioma (AO) impossible. The current evidence precludes RT alone for AO patients. Neither the RTOG nor the EORTC trial defined the role of
chemotherapy alone. A comparison of combined modality treatment with
chemotherapy alone followed by RT at progression is pending. Long-term follow-up of NOA-04 patients and results from future trials may help to clarify these questions. With more and more AO patients living 10 years or more, particular attention must be paid to late side effects, such as neurotoxicity, and careful monitoring is required for all treated patients.