Abstract
BACKGROUND: Infiltrating gliomas are progressive brain tumors with an invariably fatal prognosis. Nutritional interventions, such as the ketogenic diet (KD) and caloric restriction, have been explored as adjunct therapies. This systematic review assesses the evidence for the efficacy and safety of these dietary strategies in the management of diffuse gliomas. METHODS: A systematic search was conducted in PubMed, covering studies up to February 23, 2024. Inclusion criteria were English-language clinical and observational studies that examined the impact of dietary interventions on diffuse glioma outcomes. Studies were evaluated for risk of bias using the Cochrane Risk of Bias 2 (RoB 2) tool and synthesized descriptively due to the heterogeneity of study designs and outcomes. RESULTS: Eighteen studies (2 randomized clinical trials [RCTs] and 16 observational studies) met the inclusion criteria. The RCTs, classified as high-quality evidence, did not demonstrate significant survival benefits from dietary interventions. Observational studies, while supporting the feasibility and safety of these interventions, provided inconsistent evidence regarding their efficacy in improving overall survival (OS) or progression-free survival (PFS). Methodological limitations, including small sample sizes, variability in dietary adherence, and patient heterogeneity, were common across studies. DISCUSSION: The evidence suggests that while dietary interventions like KD and caloric restriction are generally safe and feasible for diffuse glioma patients, their efficacy in improving survival outcomes remains inconclusive. Limitations such as small sample sizes and variability in adherence underscore the need for larger, well-designed trials to evaluate the clinical benefits of these interventions.