Gliomatosis Cerebri: Predispositions and Predictors of Behavior (P6.152)

Objective: Investigate possible predisposing factors of GC, such as history of autoimmune disorders and cancer. We also propose prediction of tumor behavior based on clinical, histomolecular and imaging characteristics. Background: Gliomatosis cerebri (GC) was removed as a unique brain tumor entity from the 2016 WHO classification of CNS tumors, but remains a radiographic descriptor of diffuse brain involvement of low/high grade glioma. The mechanisms by which certain gliomas become widely multifocal, however, remains poorly understood and have not been fully explained by molecular, histologic, or genetic tumor features. We propose that the host immune microenvironment might play a significant role in glioma migrational behavior and could be a predictor of secondary progression and guide treatment. Design/Methods: We reviewed 58 cases of primary and secondary GC treated at MD Anderson Cancer Center from 2011 to 2017 to stratify epidemiological, tumor, and patient clinical features to better understand this disease pattern. Results: Median age at GC diagnosis was 57-years, and primary GC comprised 83% (n=48) of the cases. As previously reported, astrocytic histology was the most common (93%, n=54). Median follow-up was 13.5 months. Seventy-six percent (n=45) of cases were exclusively supratentorial, and the temporal lobe was most frequently involved (76%, n=45). Interestingly, 9% (n=5) of cases has leptomeningeal carcinomatosis. The most common presenting symptom was headaches (28%, n=16). The majority (67%, n=39) of patients had KPS ≥90. Here, we identified two distinct populations. First, having prior cancer history (19%, n=11) which presented most commonly as IDH-mutated low grade glioma. A second population reported premorbid autoimmune disease (26%, n=15) which were disproportionately high-grade gliomas. Median overall survival was 21 and 11 months, respectively. Conclusions: Understanding biological drivers of tumor migration are critical for tumor control. We propose that closer evaluation of brain tumor patient’s premorbid systemic disease could serve as a predictor of tumor migration patterns an aggressiveness. Disclosure: Dr. Santos Pinheiro has nothing to disclose. Dr. Gatson has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Novocure (Optune). Dr. Kamiya Matsuoka has nothing to disclose. Dr. Fuller has nothing to disclose. Dr. Weinberg has nothing to disclose. Dr. Tremont has nothing to disclose. Dr. De Groot has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Celldex (rindopepimit); Deciphera Pharmaceuticals (see above), AbbVie (ABT-414), FivePrime Therapeutics, Inc. (cabiralizumab),Genentech (bevacizumab); Celldex (see above); Foundation Medicine, Inc. (diagnostics, genomic testing platform); Novogen (GDC-008. Dr. De Groot has received royalty, license fees, or contractual rights payments from DSMB: VBL Therapeutics (VB111); Novella (ICT-107). Dr. De Groot holds stock and/or stock options in Ziopharm Oncology, Gilead. Dr. De Groot has received research support from Sanofi-Aventis (XL765); Astrazeneca (AZD 0156); EMD-Serono (M2698, Pimasertib); Eli Lilly (numerous durgs); Novartis (numerous durgs); Deciphera Pharmaceuticals DCC2618, altiratinib), Mundipharma (EDO-S101). Dr. Loghin has nothing to disclose.