Adjuvant Procarbazine, Lomustine, and Vincristine Improves Progression-Free Survival but Not Overall Survival in Newly Diagnosed Anaplastic Oligodendrogliomas and Oligoastrocytomas: A Randomized European Organisation for Research and Treatment of Cancer Phase III Trial

A total of 368 patients were included. The median follow-up time was 60 months, and 59% of patients have died. In the RT arm, 82% of patients with tumor progression received chemotherapy. In 38% of patients in the RT/PCV arm, adjuvant PCV was discontinued for toxicity. OS time after RT/PCV was 40.3 months compared with 30.6 months after RT only (P = .23). RT/PCV increased PFS time compared with RT only (23 v 13.2 months, respectively; P = .0018). Twenty-five percent of patients were diagnosed with combined 1p/19q loss; 74% of this subgroup was still alive after 60 months. RT/PCV did not improve survival in the subgroup of patients with 1p/19q loss.

Adjuvant PCV chemotherapy does not prolong OS but does increase PFS in anaplastic oligodendroglioma. Combined loss of 1p/19q identifies a favorable subgroup of oligodendroglial tumors. No genetic subgroup could be identified that benefited with respect to OS from adjuvant PCV.