Although not recommended by NCCN, or for that matter any study, most neuro-oncologists are now using combined Temodar and radiation postoperatively for anaplastic oligodendroglioma. Regardless of molecular genetic status, the most commonly recommended treatment in a questinnaire survey of neuro-oncologists was the use of concurrent temozolomide and radiotherapy followed by adjuvant temozolomide (18%-34%).
The role of chemotherapy for the treatment of oligodendroglioma is well established by several studies using nitrosourea-based therapy. Most used procarbazine, lomustine (CCNU), and vincristine, a combination chemotherapy regimen (ie, PCV) developed by Levin and coworkers. Patients with pure and mixed oligoastrocytic tumors, newly diagnosed, and recurrent mixed tumors responded to this therapy before receiving radiotherapy. Despite prolonged responses, most patients experience disease relapse and ultimately die of progressive disease. The median time for recurrence was at least 16 months in partial responders and at least 25 months in complete responders. Recurrent tumors are not cured by PCV, and the intensity of treatment may be limited by the bone marrow reserve.
Several recent studies evaluated the role of temozolomide as second-line chemotherapy for recurrent oligodendroglioma and showed a response rate of about 25% for patients relapsing after PCV therapy. The EORTC study evaluated temozolomide as a first-line chemotherapy for recurrent OD and showed a response rate of 54%, with 39% of patients remaining free from progression at 12 months.
A phase III study preliminary findings reported by Cairncross et al, comparing radiation therapy versus chemotherapy plus radiation in patients with newly diagnosed anaplastic OD and mixed OD, showed overall similar survival in both groups (4.8 y for radiotherapy plus chemotherapy group vs 4.5 y for radiotherapy alone). However, disease progression-free interval was longer for the combined therapy group (2.6 y vs 1.9 y for radiotherapy alone group). Thus it is not yet a standard of care.