OS04.8.A UNRAVELLING MENTAL AND PHYSICAL FATIGUE IN PATIENTS WITH LOW-GRADE GLIOMA TREATED WITH PROTON RADIATION THERAPY

Abstract BACKGROUND Fatigue is a common consequence of low-grade gliomas (LGG), but its specific nature and progression over time has not been extensively studied. Additionally, the effects of proton radiation therapy on fatigue are unclear. Although particularly mental fatigue is considered characteristic for patients with brain disorders, the majority of studies in patients with LGG have considered fatigue as a unitary construct or focused on physical fatigue only. Therefore, this study aimed to examine 1) whether the prevalence and severity of mental fatigue differ from physical fatigue in patients with LGG 2) whether fatigue changes after treatment with proton radiation therapy and chemotherapy; 3) the specific determinants of mental and physical fatigue, including cognitive impairments, affective symptoms and tumor-related characteristics. MATERIALS AND METHODS 148 patients with IDH mutated astrocytoma and oligodendroglioma grade 2 and 3 were evaluated after surgery and before start of proton- and chemotherapy (T0). 98 patients completed the follow-up (2.5 years after treatment, T1) until now. Mental and physical fatigue were measured with the Dutch Multifactor Fatigue Scale (DMFS). Neuropsychological tests were used to examine cognitive impairments, questionnaires were used to examine affective symptoms and tumor-related characteristics, such as tumor volume and white matter lesions were examined. Descriptive statistics, Spearman’s correlations and hierarchical multiple regression analyses were performed. RESULTS Before treatment (T0), 38% of the patients reported severe mental fatigue, while 22% reported severe physical fatigue. At T0, the full hierarchical model (including demographics, cognitive measures, affective symptoms and tumor-related characteristics) explained 29% of variance (p = <.001) in the level of mental fatigue in patients with LGG. Significant predictors in this model were female gender, symptoms of anxiety and depression. The model for physical fatigue explained 24% of variance (p = <.001), with lower educational level, larger tumor volume and symptoms of depression identified as significant predictors. 2.5 years after adjuvant therapy (T1), 45% of the subgroup of 98 patients reported severe mental fatigue, while 27% of the patients reported severe physical fatigue. CONCLUSION Mental fatigue can be distinguished from physical fatigue in patients with LGG, characterised by a higher prevalence and unique determinants. Mental and physical fatigue increase after adjuvant therapy. These findings suggest that mental fatigue requires independent diagnostic attention and likely demands a different therapeutic approach compared to physical fatigue.