Abstract AIMS To identify factors which impact prognosis in a historical cohort of diffuse low grade gliomas (DLGG) if anal- ysed according to updated WHO 2021 classification. These factors and concomitant outcomes are benchmarked against European Organisation for Research and Treatment of Cancer (EORTC) and Radiation Therapy Oncology Group (RTOG) scores in this cohort. METHODS Adult patients diagnosed with IDH mutant DLGG between January 2010 and December 2019 at the Institute of Neurological Sciences were retrospectively identified from the West of Scotland Neuro-Oncology MDT and out- comes analysed up to December 2022. The demographic and clinical variables were extracted from electronic case notes and categorised to calculate EORTC and RTOG scores. Univariate and multivariate analysis were car- ried out on factors predicted to affect outcomes using IBM SPSS. RESULTS 64 patients were identified. The median age was 41 years(range:23-69) and 43.8% were male. 21 patients(28.1%) underwent gross total resection(GTR) and 15(23.4%) underwent biopsy. 18(28.1%) patients were high-risk by EORTC score and 55(85.9%) by RTOG. Patients undergoing subtotal resection (STR) or GTR were more likely to be younger (mean:46.6 years for biopsy, 39.8 years STR/GTR, p=0.047) and have a tumour measuring 6 cm compared to those undergoing biopsy (32 STR/GTR 6cm, 17 STR/GTR ≥6cm, p=0.009). Overall mean survival was 112 months. 46(70.3%) of patients were alive in December 2022. GTR was the only variable significant on multivariate analysis of overall survival (HR:0.193, CI:0.044-0.851, p=0.03). 41 patients(64.1%) had progression of disease, with age ≤40 years, male sex and undergoing adjuvant treatment rather than surgery alone associated with an improved progression free survival(PFS) on multivariate analysis(p= 0.001). Neither the EORTC or RTOG scores had prognostic value in predicting the PFS or the OS. CONCLUSION Maximal extent of resection was associated with better overall mean survival. The utility of the EORTC and RTOG scores is limited following the 2021 WHO Classification.
Minnis et al. (Mon,) studied this question.