MGMT promoter gene methylation and neurological scale improvement in glioma: a cohort study [version 1; peer review: 2 approved with reservations]

Background: Glioma is one of the most common primary brain tumours and conveys a dismal prognosis despite aggressive treatment. Several biomarkers have been studied in the hope of yielding better diagnostic accuracy and improving patient management. Besides survival, functional and neurological disability are concerns that have no lesser importance. In 2017, a disease-specific assessment tool – the Neurologic Assessment in Neuro-Oncology (NANO) scale – was developed to measure neurologic function in neuro-oncology cases. We sought to determine biomarkers that might be associated with neurological scale improvement in glioma patients. Methods: Glioma grade II-IV patients were recruited from three major hospitals in Jakarta-Tangerang. Isocitrate dehydrogenase (IDH) mutation and O6-methylguanine-DNA methyltransferase (MGMT) promoter gene methylation were tested, as well as patients’ neurological function before surgery and three months after. Improvement in neurological scale (NANO scale) was considered positive if there was a decrement of ≥1 of the scale. Results: There were 54 patients included in the study. Mean age was 43.63 (14.723) years old, and 61.1% were male. As much as 16 (29.6%) carried a mutation in codon 132 of the IDH1 gene, and 33 (61.1%) were MGMT methylated. Median NANO scale score before and three months after surgery was 4 (0-12) and 3 (0-12), respectively. Neurological improvement was found in 44 (81.5%) of the patients. Among patients with MGMT promoter gene methylation, 90.9% showed neurological improvement (p=0.035; OR=5; 95%CI 1.122-22.272). Conclusions: Gliomas with MGMT promoter gene methylation are more likely to show neurological improvement three months after surgery.