Treatment Recommendations for Anaplastic Oligodendrogliomas That Are Codeleted

摘要

Abstract: Anaplastic oligodendroglioma (AO) is a rare malignant tumor occurring in adults. Despite early indications of chemosensitivity, no clinical trial had demonstrated a benefit of chemotherapy beyond that of radiotherapy alone. Now, however, the Radiation Therapy Oncology Group (RTOG) 9402 and the European Organisation for Research and Treatment of Cancer (EORTC) 26951 studies investigating PCV (procarbazine [Matulane], lomustine [CeeNU], and vincristine) and radiation therapy vs radiation alone both show improved outcomes in patients with the 1p/19q codeletion who received PCV and radiation therapy. These differences were detected with additional follow-up after publication of the initial results in 2006, when no differences in survival were detected. The two studies have also validated the use of the 1 p/19q codeletion as a predictive biomarker in AO. Many will debate the wisdom of adopting PCV therapy as standard of care because of the greater toxicity of PCV compared with temozolomide (Temodar). Nonetheless, although important questions still remain regarding chemotherapy choice, sequence, and dosing, the answers to which will require additional large phase III trials, radiotherapy alone is no longer appropriate therapy for 1 p/19q codeleted AOs. Introduction Anaplastic oligodendroglioma (AO) is a rare malignant tumor with features of oligodendroglial lineage and histologi-' cal features corresponding to World Health Organization (WHO) grade III.[1] The reported annual incidence rates of AO ranges from 0.07 to 0.18 per 100,000 person-years and comprise only 0.5% to 1.2% of all primary brain tumors. Only about 30% of oligodendroglial tumors have anaplastic features. The peak incidence of AO is between 45 and 50 years of age; patients on average are approximately 7 to 8 years older than those with grade II oligodendroglioma. Although not proven, this age difference may correspond to the mean time to progression from a grade II oligodendroglioma (6 to 7 years). Similar to low-grade (WHO grade II) oligodendroglioma, AO tends to preferentially occur in the frontal lobe, with the temporal lobe the next most common location. Seizures are the main presenting symptom, both in patients who develop de novo AO and in patients with a prior longstanding history of oligodendroglioma who undergo transformation to AO.