Glioblastoma multiforme among elderly; a tertiary care center experience (P4.242)

BACKGROUND: Uncertainty persists about the tolerability of concurrent temozolomide (TMZ) plus radiation therapy (RT) in elderly patients with glioblastoma (GBM). OBJECTIVE: We performed a retrospective study between 2010-2014 in our University center to compare the clinical outcome of unselected elderly GBM patients aged 55-69 and ≥70. METHODS: We divided our group in 4 homogeneous adjuvant treatment modalities: concurrent chemoradiation therapy (CCRT) with standard 60Gy RT (SRT); CCRT with hypofractionated 40Gy RT (HRT); HRT alone; and TMZ alone. RESULTS: Among 171 patients identified, median age was 66(55-83), and mOS 11.4mo[95[percnt]CI(9.2-13.3)]. The 116(68[percnt]) patients aged 55-69 had a much better mOS compared to the 55(32[percnt]) aged ≥70 (13.3 vs 6.6 months; p=0.001). Among patients who underwent a biopsy (n=43; 25[percnt]), there was no survival difference in patients aged 55-69 and ≥70 (4.7 vs 3.9 months; p=0.252). However, patients aged 55-69 survived twice as those aged ≥70 if they had a partial or complete resection (15.0 vs 7.9 months; p=0.003; HR=2.0; 95[percnt]CI[1.26-3.19]). According to treatment modalities; 109/171 patients were treated with CCRT-SRT, and there was no survival difference between the 95(87[percnt]) patients aged 55-69 and the 14(13[percnt]) aged ≥70 (14.4 vs 13.2 months; p=0.798). Only 15/171(9[percnt]) patients received CCRT-HRT; 3(20[percnt]) aged 55-69 and 12(80[percnt]) ≥70, with mOS 28.4 vs 11.1 months (p=0.075). There was no difference in survival of patients aged ≥70 treated with CCRT-SRT vs CCRT-HRT (13.2 vs 11.1 months, p=0.248). Post-CCRT adjuvant TMZ was given to 119(70[percnt]) patients; 72[percnt] aged 55-69 and 28[percnt] ≥70, with 4.5 vs 2.5 median number of cycles (p=0.013). CONCLUSIONS: Our data suggests no survival advantage to CCRT-SRT over CCRT-HRT in unselected elderly patients ≥70y, despite they have a worse prognostic than youngers. However, only 9[percnt] of our population received CCRT-HRT, meaning the elderly population was treated as younger with equivalent survival. Theses results need prospective confirmation. Disclosure: Dr. Lapointe has nothing to disclose. Dr. Florescu has received research support from Astrazeneca; Bristol-Myers Squibb. Dr. Simonyan has nothing to disclose. Dr. Michaud has nothing to disclose.