418O - Temozolomide for 1P19Q Co-Deleted and Partially Deleted Gliomas

Abstract

Background Radiotherapy with procarbazine, lomustine and vincristine improves overall survival (OS) in patients with 1p19q codeleted anaplastic oligodendroglioma (AOD)/anaplastic oligoastrocytoma (AOA). This retrospective review investigates outcomes with upfront temozolomide (TMZ) alone in 1p19q codeleted/partially deleted AOD, AOA, oligodendroglioma (OD) or oligoastrocytoma (OA).Methods Patients (pts) with 1p19q codeleted/partially deleted AOD, AOA, OD and OA were analyzed for OS and progression free survival (PFS) using Kaplan-Meier method, and prognostic factors using Cox proportional hazard model.Results A total of 106 pts (Dec 97-Dec 13) were included. Median (med) age was 40 yrs (19-66), 58 (55%) male, performance status (PS) 0 in 80 (75%) pts. 1p19q status was codeleted in 66 (62%), incompletely codeleted in 27 (25%), 1p or 19q loss alone in 4 (4%) and 9 (8%) pts respectively. Upfront treatment was given in 72 (68%) pts; TMZ alone in 52 (49%) was well tolerated with med 12 cycles (1-24). Med time to radiotherapy in 47 pts (44%); 34.7 mo, 41.2 mo in 9 pts with codeleted/incompletely codeleted AOD who received upfront TMZ alone. Med OS was not reached for all groups (med follow up 5.1yrs) [Table]. On multivariable analysis, PS 1 vs 0 (Hazard ratio [HR] 2.78, 95% confidence interval [CI] 1.57-4.93, p<0.001) and 1p19q codeletion/incomplete deletion vs 1p or 19q loss alone (HR 0.36, 95% CI 0.18-0.74, p=0.005) were prognostic for PFS. Isocitrate dehydrogenase-1 status is pending.Group N Med PFS mo (95% CI) 2yr PFS (%) (95% CI) 5yr PFS (%) (95% CI) 5yr OS (%)(95% CI)All 106 46.3 (37.9, 56.7) 81.1 (71.6, 87.6) 34.0 (23.5, 44.7) 90.9 (81.6, 95.6)AOD 47 45.7 (30.1,63.6) 78.4 (62.5, 88.2) 38.4 ( 22, 54.5) 88.7 (72.2, 95.7)AOA 9 Not Reached 87.5 (38.7, 98.1) 65.6 ( 15.7, 90.9) 100 (100, 100)OD 42 46.1 (32.1,58.8) 79.1 (62.5, 89) 32.0 ( 16.7, 48.4) 90.3 (72.6, 96.8)OA 8 44.7 (26.2,58.8) 100 (100, 100) 12.5 ( 0.7, 42.3) 100 (100,100)AOD ? codeleted/incomplete-upfront TMZ alone 32 46.3 (32.0,90.8) 84.3 (63.4,93.8) 42.1 (20.1,62.8) 95.5 (71.9,99.3)Conclusion Upfront TMZ alone in 1p19q codeleted/incompletely deleted AOD was tolerated with favourable 5yr OS and may be a treatment option for this population.