Gliomatosis cerebri: a monocentric real-life experience

Aim: Gliomatosis cerebri (GC) is defined as a rare pattern of growth of diffuse gliomas involving three or more cerebral lobes. Given its rarity, it is difficult to define prognostic factors and standard of treatment. We retrospectively analyzed patients (PT) with GC from a single institution with the aim of identifying the main prognostic factors and to assess optimal management. Methods: Medical records were reviewed of patients ≥ 18 years with a histological and/or radiological diagnosis of GC (with no contrast enhancement) occurring between 2006 and 2017. Median progression free survival (PFS) and overall survival (OS) were calculated by the Kaplan-Meier method. Results: We analyzed 33 PT, 22 males and 11 females; Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 0-1 in 21 of the patients. Twenty-two PT underwent biopsy: 16 were astrocytomas and 6 oligodendrogliomas. O6-methylguanin-DNA-methyltransferase (MGMT) was detected in 14 cases, and it was methylated in eight cases. Isocitrate dehydrogenase 1 (IDH1) was analyzed in 16 PT, and it had mutated in 10 of them. Nine PT (27％) were treated with radiation therapy (RT) plus concurrent temozolomide (TMZ), 22 PT (67％) received TMZ alone, and 2 PT (6％) underwent RT alone. We reported "complete response" in 1 patient (3％), partial response in 9 PT (27％), and stable disease in 15 PT (45％), while 8 PT (25％) had a progressive disease. For all PT, PFS and OS were 19.1 and 30.7 months, respectively. For ECOG PS 0-1 and ≥ 2, PFS was 34.6 months vs. 3.4 months (P < 0.0001) and OS was 42 months vs. 8.9 months (P < 0.0001), respectively. Methylated MGMT was associated with longer PFS (41.6 months vs. 8.9 months, P = 0.05) and OS (52.7 months vs. 14.6 months, P = 0.009); PFS for IDH1 mutation and IDH wild-type was 52.7 months vs. 8.9 months (P = 0.006) and OS was 52.7 months vs. 41.7 months (P = 0.02), respectively. No significant difference was detected as regards treatments. With regard to histological subtype, OS was 42.0 months vs. 52.7 months (P = 0.8) and PFS was 41.6 months vs. 28.6 months (P = 0.7) for astrocytoma vs. oligodendroglioma, respectively. PT with treatment response showed a longer OS. PT receiving second-line treatment had a longer OS of 30.7 months vs. 6.5 months (P = 0.04). Conclusion: ECOG PS, MGMT methylation, and IDH1 mutational status seem to have an important prognostic significance, while the type of treatment does not seem to affect survival. Treatment response could be a surrogate marker for survival.