From Metabolism to Mood: Imaging the Neuropsychiatric Consequences of Chemotherapy-Induced Brain Changes

Objectives: With the increasing number of cancer survivors due to advances in therapy, chemotherapy-related cognitive and mood disturbances-collectively termed Chemotherapy-Related Cognitive Impairment (CRCI) -have become a recognised clinical concern. This study aimed to assess chemotherapy-induced neuropsychiatric changes in breast and lung cancer patients and correlate them with alterations in brain glucose metabolism on 18 F-FDG PET/CT using both visual assessment and NeuroQ software analysis. Material and Methods: This study included 56 patients undergoing cytotoxic systemic chemotherapy who were evaluated twice, at baseline and at 3-6 weeks after 2 chemotherapy cycles. Cognitive and neuropsychiatric assessments were performed using the Montreal Cognitive Assessment -Basic (MoCA-B), Hamilton Anxiety (HAM-A), and Hamilton Depression (HAM-D) scales. Brain glucose metabolism from brain 18 F-FDG PET/CT examinations was quantified using Z scores from NeuroQ, representing deviations from the mean of age- and sex-matched controls. Data analysis was conducted using Microsoft Excel and R software. Results: Post-chemotherapy evaluation revealed worsening cognitive impairment, anxiety, and depression. These neuropsychiatric changes correlated with reductions in brain glucose metabolism. Significant moderate correlations were found between frontal Z-score changes and MoCA-B (r = 0.77, p < 0.05), temporal Z-scores and HAM-A (r = 0.6, p < 0.05) and temporal Z-scores and HAM-D (r = 0.75, p < 0.05). No significant associations were noted with age, sex, or metastatic status. Conclusion: Cytotoxic chemotherapy may be associated with detectable alterations in cerebral glucose metabolism accompanied by cognitive and mood disturbances. The temporal course of these metabolic changes remains to be established. 18 F-FDG PET/CT may help characterise metabolic correlates of cancer-related cognitive impairment, although currently, its clinical role remains exploratory.