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Page 2 of 8 Bellu et al. J Cancer Metastasis Treat 2021;7:29 https://dx.doi.org/10.20517/2394-4722.2021.89

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.

Keywords: Low-grade gliomas, gliomatosis cerebri, temozolomide, IDH, radiotherapy

INTRODUCTION
According to the 2016 World Health Organization (WHO) Classification of tumors of the Central Nervous
System, gliomatosis cerebri is no longer a distinct pathological entity, being designated as a pattern of
diffuse and extensive growth of glioma cells. It includes astrocytic and oligodendroglial tumors, involving
[1]
three or more cerebral lobes, usually bilateral, with a frequent extension to infratentorial structures .
However, GC remains a complicated entity to treat, with great heterogeneity in clinical features and
outcome. Symptoms and radiological appearance are non-specific, and, thus, it can be confused with other
neurological diseases ; on magnetic resonance imaging (MRI), GC usually shows diffuse infiltration
[2]
predominantly of white matter, with T2-weighted and fluid-attenuated inversion recovery (FLAIR)
hyperintensity.

With regard to the treatment of GC, optimal management is still unclear. Surgery is used for focal biopsy
and the role of radiotherapy and chemotherapy is discordant.

The aim of our paper is to describe our real-life experience in GC by retrospective analysis and to
investigate the main prognostic factors and therapeutic management.

METHODS
We retrospectively analyzed all consecutive patients diagnosed with GC who visited our oncological center,
the Veneto Institute of Oncology-IRCCS, in Padua between January 2006 and December 2017. Each patient
had to meet the following criteria: age ≥ 18 years, MRI-T2 or FLAIR sequences showing the interest of at
least three cerebral lobes, and with the aspect of diffuse glioma with no contrast enhancement. Histological
diagnoses were based on the 2009 or 2016 WHO classification, depending on the year in which the
intervention was performed.

Demographic data, age at diagnosis, biopsy execution, histological diagnosis, O6-methylguanin-DNA-
methyltransferase (MGMT) promoter methylation, IDH1-2 mutation, type of therapy, radiological aspects,
and response and patient outcomes were recorded. In particular, the MGMT promoter methylation status
was investigated by polymerase chain reaction (PCR) or pyrosequencing and the IDH1-2 mutation status
was performed by immunohistochemistry and PCR; radiological response was retrospectively evaluated by