Is there a benefit to PCV (procarbazine, CCNU, and vincristine) chemotherapy in the management of higher risk low-grade gliomas (patients with grade 2 astrocytoma, oligoastrocytoma, or oligodendroglioma who were younger than 40 years of age and had undergone subtotal resection or biopsy or who were 40 years of age or older and had undergone biopsy or resection of any of the tumor)?