Long-term follow-up results of EORTC 26951: A randomized phase III study on adjuvant PCV chemotherapy in anaplastic oligodendroglial tumors (AOD).

Abstract

2 Background: AOD are chemotherapy-sensitive tumors especially if 1p/19q co-deleted. Between 1995 and 2002 the EORTC Brain Tumor Group conducted a prospective phase III study on adjuvant procarbazine, CCNU and vincristine chemotherapy (PCV) in AOD. We now present long-term follow-up. Methods: Patients (pts) with locally diagnosed newly diagnosed AOD were randomized between radiotherapy (RT, 33 x 1.8 Gy) and the same RT followed by 6 cycles of standard PCV (RT/PCV). Primary endpoints were overall survival (OS) and progression-free survival (PFS). 1p/19q status, IDH status and MGMT promoter methylation were determined in 300, 167, and 186 pts respectively. Results: Between 1996 and 2002, 368 pts were included. At the time of analysis 281 pts (76.4%) had died. Median PFS after RT/PCV was significantly longer compared to RT alone (24.3 months versus 13.21 months, hazard ratio [HR] 0.66, [95% confidence interval (95% CI) 0.52, 0.83]). More RT arm patients received chemotherapy at progression (75% vs 53%). Median OS was also significantly prolonged in the RT/PCV arm (42.3 months vs 30.6 months for the RT arm, HR 0.75 [95% CI 0.60, 0.95]). 1p/19q co-deleted patients (n = 76) treated with RT/PCV had improved OS compared to RT arm pts (median OS not reached vs 113 months; HR 0.54, p = 0.0487). In the 224 patients without 1p/19q co-deletion the difference in OS was non-significant (OS RT/PCV arm 25 months vs 22 months in the RT arm, HR 0.82, p = 0.18; test for interaction p = 0.22). There was a slight trend towards improved OS in MGMT methylated and IDH mutated tumors versus unmethylated and IDH wild type tumors (Table). Conclusions: The addition of PCV to RT increases PFS and OS in AOD. Pts with 1p/19q co-deletion appear to benefit most from the addition of PCV, with a trend for improved OS in pts with MGMT methylation and IDH mutations. [Table: see text]