Phase III randomized study of radiotherapy plus procarbazine, lomustine, and vincristine with or without BUdR for treatment of anaplastic astrocytoma: final report of RTOG 9404.

Overview

abstract

PURPOSE: This study was an open-label, randomized Phase III trial in newly diagnosed patients with anaplastic glioma other than glioblastoma multiforme comparing external beam radiotherapy (EBRT) plus adjuvant procarbazine, cyclohexylchloroethylnitrosurea (lomustine), and vincristine (PCV) chemotherapy with or without bromodeoxyuridine (BUdR) given as a 96-h infusion each week of RT. METHODS AND MATERIALS: Only patients 18 years or older with newly diagnosed anaplastic glioma were eligible. A central pathology review was accomplished for most patients, but was not mandated before registration. The study had initially opened as a Northern California Oncology Group trial in 1991, becoming an Intergroup Radiation Therapy Oncology Group (RTOG), Southwestern Oncology Group and the North Central Cancer Treatment Group study in July 1994. A total accrual of 293 patients was planned for the sample size, using survival as the primary end point. The experimental arm (RT/BUdR + PCV) was to be compared with the control arm (RT + PCV) using a one-sided alpha = 0.05, with a power of 85% for detecting an increase in median survival from 160 to 240 weeks, assuming a 3-year follow-up after enrollment completion. RESULTS: Between July 1994 and August 1996, 134 patients were randomized to EBRT + PCV (non-BUdR patients) and 134 to EBRT/BUdR + PCV (BUdR patients). The study was closed before the full-anticipated accrual on the basis of an interim analysis that predicted no survival benefit for the BUdR arm. Of the 268 patients, 41 and 37, respectively, were ineligible or canceled primarily on the basis of the central pathology review findings. Thus, 93 patients and 97 patients were eligible/analyzable in the non-BUdR and BUdR arms, respectively. Patient characteristics were well balanced in both arms, with most <50 years old and in the RTOG recursive partitioning analysis (RPA) Class I category. The minimal potential follow-up was 4.6 years. The median survival for non-BUdR patients was 4.1 years compared with 4.6 years for the BUdR patients (p = 0.61). The 4-year overall survival rate was 51% in both arms. For RPA Class I patients (the best prognostic class), the median survival had not been reached for non-BUdR patients (4-year survival rate 61%) and was 5.6 years for BUdR patients (4-year survival rate 64%; p = 0.91). Each arm was also compared with the RTOG historical database for RPA Class I patients with no statistically significant difference found in overall survival (BUdR vs. historical, p = 0.31 and non-BUdR vs. historical, p = 0.48). Grade 4 toxicity occurred in 15 and 17 patients in the non-BUdR and BUdR arms, respectively, with one treatment-related death in the BUdR group. CONCLUSION: No survival advantage was noted by adding BUdR to EBRT and PCV in this patient population