P11.04 Autonomy duration as analyzed by KPS≥70 cumulative time in patients with biopsy-only glioblastoma (BO-GBM). A sub-analysis of the Timone cohort

Abstract

Abstract BACKGROUND Improvement or maintenance of autonomy is a crucial and understudied issue for glioblastoma (GBM) patients whose outcome is poor. Biopsy-only GBM (BO-GBM) is a situation where survival is short and independence is of particular importance. Our objective was to explore functional outcome in biopsy-only patients. MATERIAL AND METHODS A regional glioma SIRIC cohort was conducted at CHU Timone in 2014–2017 and we retrospectively reviewed the BO-GBM subgroup. We prospectively collected age, corticosteroid dose, tumoral surface, treatment allocated and completed, and survival outcome. Functional independence was analyzed as a cumulative time of Karnofsky performance status (KPS) ≥70 from the date of diagnosis until death. We analyzed potential factors associated to time with KPS ≥70. RESULTS Among 535 patients enrolled in the cohort, surgery was restricted to biopsy in 139 patients (BO-GBM). Mean tumoral surface measured on gadolinium-enhanced T1-weighted MRI was 1198mm2 (min: 65; max: 4515mm2). Mean steroid dose at diagnosis was 50mg prednisolone per day. Corticosteroid dose was ≥50mg prednisolone per day for 77 patients and <50mg per day for 56 patients. Fifty-four patients (39%) were referred to radiotherapy-temozolomide (RT-TMZ), 68 (49%) considered unfitted for RT received chemotherapy upfront only (CT-UF), and 17 patients (12%) were referred to palliative care only. Median overall survival (OS) was 7.5 months (95%CI: 6.0–9.2), 14.0 months (95%CI: 9.7–18.7) and 6.0 months (95%CI: 4.6–7.7) for BO-GBM, RT-TMZ and CT-UF respectively. At diagnosis, 81 (58.3%) patients presented with self-care capacity (KPS ≥ 70%). For these patients, median time of autonomy preservation was 7.6 months (95%CI: 6.1–9.0). Median time of autonomy preservation differed according to treatment modalities: it was 8.6 months (95%CI: 5.9–11.3) versus 6.3 months (95%CI: 2.9–9.7) for RT-TMZ versus CT-UF group respectively (p<0.001). In univariate analysis, time with KPS ≥ 70% was correlated with age (p=0.001), initial KPS (p<0.001), tumoral surface measured on gadolinium-enhanced T1-weighted MRI (p=0.03) and corticosteroid dose (p=0.001). In multivariate analysis, time with KPS≥70 was correlated with age (p=0.001) and KPS at diagnosis (p<0.001). CONCLUSION Patients with inoperable GBM referred to radiotherapy-temozolomide present a valuable duration of functional independence, although shorter in patients not referred to RT. Duration of functional independence could be considered in addition to PFS and OS for treatment evaluation in patients with GBM.