Radiation Therapy With or Without Chemotherapy in Treating Patients With Anaplastic Oligodendroglioma

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Radiation therapy uses high-energy x-rays to damage tumor cells. Combining chemotherapy with radiation therapy may kill more tumor cells. PURPOSE: Randomized phase III trial to compare the effectiveness of radiation therapy with or without chemotherapy in treating patients who have anaplastic oligodendroglioma.

OBJECTIVES: * Compare the overall survival and time to tumor progression in patients with unifocal or multifocal, supratentorial, pure or mixed anaplastic oligodendroglioma treated with radiotherapy with or without procarbazine, lomustine, and vincristine (PCV). * Compare the toxic effects of these 2 regimens in these patients. * Compare the quality of life and neurologic function of patients treated with these 2 regimens. OUTLINE: This is a randomized study. Patients are stratified by age (under 50 vs 50 and over), Karnofsky performance status (60-70% vs 80-100%), and tumor grade (moderately vs highly anaplastic). Within 8 weeks after diagnostic surgery, patients are randomized to 1 of 2 treatment arms. * Arm I: Within 2 weeks after randomization, patients receive oral lomustine on day 1, oral procarbazine on days 8-21, and vincristine IV on days 8 and 29 (PCV). Treatment continues every 6 weeks for 4 courses in the absence of disease progression or unacceptable toxicity. Beginning within 6 weeks after day 29 of course 4, patients undergo radiotherapy 5 days a week for 5.6 weeks followed by boost radiotherapy 5 days a week for 1 week. * Arm II: Within 2 weeks after randomization, patients undergo radiotherapy as in arm I. Quality of life is assessed at baseline; at time of CT or MRI scans during study; and every 3 months for 1 year, every 4 months for 1 year, every 6 months for 3 years, and then annually thereafter after completion of study therapy. Patients are followed every 3 months for 1 year, every 4 months for 1 year, every 6 months for 3 years, and then annually thereafter. PROJECTED ACCRUAL: A total of 292 patients (146 per arm) will be accrued for this study within 5.4 years.