Cognitive Decline in Glioblastoma Patients with Different Treatment Modalities and Insights on Untreated Cases

Background: Cognitive decline is common in patients with Glioblastoma multiform (GBM) even with treatment modalities, and often presents as impairments in memory, attention, language, and other cognitive functions. In addition, cognitive deficits can affect the quality of life, functional independence, and survival and are associated with other psychological disorders such as anxiety and depression. Methods: This literature review evaluates the cognitive deficits in GBM patients with and without treatment. Then we explore the relationship between tumor characteristics such as size, location, histology, and patient characteristics such as age and education level, as well as whether existing therapies, such as surgery, chemotherapy, and radiotherapy, and any change in cognitive function. Results: Cognitive impairment in patients with GBM is affected by tumor characteristics, patient-specific factors, and treatment modalities however some treatments such as a combination of surgery, radiotherapy, and chemotherapy, initially were associated with improvement of cognitive outcomes because the treatments are related to reduced tumor burden, alleviation of cerebral edema, reduced mass effect, and then indirect effects of improved mental health and mood. While certain treatments, such as radiotherapy and chemotherapy pose risks of delayed neurotoxicity, the overall preservation and improvement of cognitive function were more pronounced in treated versus untreated patients. However, the studies suggest that beyond a certain level of treatment aggressiveness and the existence of neurotoxicity or damage, the benefit of therapy is above cognitive preservation. Conclusion: This review highlighted cognitive function as an independent factor that could affect survival in GBM patients, therefore routine cognitive assessments in clinical practice is a helpful strategy to predict the prognosis, treatment planning, and rehabilitation efforts. Interventions such as neuroprotective agents, cognitive rehabilitation programs, and personalized, multidisciplinary strategies are crucial in helping to balance treatment effectiveness with cognitive preservation.