139O - Systematic review and individual patient data analysis of uncommon GBM variants: An analysis of 196 cases
|Date||17 December 2016|
|Event||ESMO Asia 2016 Congress|
|Topics|| Central Nervous System Malignancies
|Citation||Annals of Oncology (2016) 27 (suppl_9): ix42-ix45. 10.1093/annonc/mdw578|
S. Mallick, R. Benson, B. Venkatesulu, G.K. Rath
Different variant of GBM has been reported viz. Epithelioid GBM (GBM-E), Rhabdoid GBM (GBM-R), Small cell GBM (GBM-SC), Giant cell GBM (GBM-GC), GBM with neuro ectodermal differentiation (GBM-PNET) with unknown behavior.
We conducted a systematic review and individual patient data analysis of rare GBM variants. We searched PubMed, google search, and Cochrane library for eligible studies till July 1st 2016 published in English language and collected data regarding age, sex, subtype, and treatment received, DFS, OS. STATA 12 software was used for all statistical analysis.
We retrieved data of 196 patients with rarer GBM subtypes. Among these GBM-GC is commonest (51%), followed by GBM-R (19%), GBM-PNET (13%), GBM-SC (9%) and GBM-E (8%). Median age for these was 38, 40, 43.5, 69.5 and 18 years. Male: female ratio was 2:1 for GBM-E, 1:3 for GBM-SC. Maximal safe resection followed by adjuvant radiation was advocated for most of the patients. However, 6 GBM-PNET, 3 each of GBM-E, GBM-SC received Craniospinal radiation. Out of 76 patients, 50 received Temozolomide as adjuvant therapy. Median PFS and OS for the entire cohort were 8 and 16.5 months. In univariate analysis patient with a GTR had significantly better survival compared to those with a STR [23 vs. 13 months (p-0.01)]. Median OS for GBM PNET 32 months; GBM-GC 18.3 months; GBM-SC 11 months; GBM-R 12 months; and GBM-E 7.7 months (p = 0.002). 31.3%, 37.8% patients with GBM-E, GBM-R had CSF dissemination.
Overall cohort of rarer GBM variant has equivalent survival compared to GBM not otherwise specified. However, epithelioid and Rhabdoid GBM has worst survival and one third shows CSF dissemination.
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All authors have declared no conflicts of interest.