Chemotherapy-induced modulation of brain glucose metabolism in leukemia patients: A retrospective comparative study.

e18572 Background: Chemotherapy-induced cognitive impairment, or "chemo brain," is characterized by memory deficits, emotional disturbance, and impaired executive function, affecting up to 75% of cancer patients. While its mechanisms remain unclear, alterations in cellular metabolism are thought to play a key role. This study investigates the effects of chemotherapy on brain glucose metabolism in leukemia patients through region- and voxel-based analyses using high-resolution 18F-FDG PET/CT scans. Methods: This retrospective comparative study included leukemia patients treated at MD Anderson Center (January 1, 2023–August 8, 2024). Patients with brain metastasis, cognitive disorders, or psychiatric conditions were excluded. 18F-FDG PET/CT scans (Biograph Vision Quadra, Siemens Healthineers) were analyzed, with brain slices co-registered to a MiM neuro template normalized to MNI space. Age- and gender-matched subgroups were compared for region- and voxel-based analyses using the Standard Brain Atlas, and a 100-voxel threshold for significance, respectively. Mean SUVwb values were compared using two-tailed t-tests (P < 0.05, T = 1.96) in MIM software (v. 7.1.4). Results: A total of 100 leukemia patients (50 females and 50 males) were included: 51 were receiving chemotherapy within one year of the scan, 21 had received chemotherapy more than one year prior, and 28 underwent PET scans before starting chemotherapy. Significant differences in brain metabolism were observed between patients who received chemotherapy and those who did not. Hyper-metabolism was identified in the Amygdala, Fusiform Gyrus, Temporal Operculum, Parahippocampal Gyrus, and Insula, while hypo-metabolism was prominent in the Occipital Lobe, Posterior Cingulate Gyrus, Inferior Medial Frontal Gyrus, and Precuneus. Intrathecal chemotherapy was associated with hypo-metabolism in the Subcallosal Area and Thalamus, and hyper-metabolism in the Fusiform Gyrus. Temporal analysis revealed hyper-metabolism in regions such as the Temporal Operculum and Insula during or shortly after chemotherapy, transitioning to hypo-metabolism in the Occipital Lobe and Precuneus over time. These findings highlight distinct, time-dependent patterns of brain metabolism influenced by chemotherapy modality and timing. Conclusions: This study identifies alterations in brain glucose metabolism associated with chemotherapy. Hyper-metabolism was predominantly observed in regions involved in emotion, and sensory integration. In contrast, hypo-metabolism was more common in regions associated with visual processing and executive function. Temporal analysis revealed a shift from hyper- to hypo-metabolism in specific regions, suggesting progressive metabolic changes over time. These findings provide insights into the neurobiological foundation of chemotherapy-related cognitive and mood disturbances.