P17.09 * PCV CHEMOTHERAPY IMMEDIATELY FOLLOWED BY RADIOTHERAPY IN DIFFUSE LOW GRADE GLIOMAS - ABOUT A SERIES OF 12 PATIENTS

Abstract

INTRODUCTION: PCV (procarbazine, CCNU, vincristine) chemotherapy was the first association evaluated in diffuse low grade gliomas (DLGGs). Impact of temozolomide and PCV was previously assessed on growth kinetics. Nevertheless, there are no data concerning the growth kinetics of DLGGs after PCV immediately followed by radiotherapy. METHODS: We retrospectively selected patients with histological diagnosis of DLGGs from a french neuro-oncological center (Nancy) who benefited from PCV chemotherapy immediately followed by conventional radiotherapy. Clinical, neuroimaging (kinetics), pathological and molecular data were recorded. RESULTS: Twelve patients with a median age at diagnosis of 37,9 years (range 24 to 56) were selected. The median follow-up was 17,9 years (range 12,6 to 22,31). The median number of PCV cycles was 5 (range 2 to 6). The median time between the end of PCV chemotherapy and the beginning of the radiotherapy was 2,6 months (range 1 to 5). The median dose of radiotherapy was 54 Gy (range 54 to 60). During the follow-up period, 3 patients died and 3 patients presented anaplastic transformation (median time to transformation 12 years, range 11,8 to 14). The median survival was 18 years (range 12,6 to “not reached”). 2 patients developed severe neurocognitive deficits (dementia) and 1 patient presented a postradiation stroke. 10 DLGG patients had IDH1 R132H mutation, 5 patients showed a surexpression of P53 and 5 expressed alpha-internexin. Before treatment combining PCV and radiotherapy, the median spontaneous growth kinetics was 4,03 mm per year (range 2,32 to 11,26). After the combined treatment, the growth kinetics remain negative in 10 patients with a median of -1,72mm/year (range -5,36 to 1,92). The median duration of negative kinetics was 8,8 years (range 0 to 16,6). CONCLUSIONS: Despite this limited series, we reported growth kinetics data on the synergy of PCV and radiotherapy in DLGGs. The prolonged response seems longer than previous data obtained with PCV alone (median of 2,7 years). Specific neurocognitive and quality of life data will be collected.