Regional cerebral glucose metabolism of patients with malignant diseases in different clinical phases

Background: Psychological and psychiatric aspects of cancer patients have not been studied well in terms of functional neuroimaging. The aim of this pilot study was to investigate the relationship between regional cerebral metabolism and different clinical phases. Material and Methods: Relative cerebral glucose metabolism of 77 Japanese patients with various types of malignant diseases was studied by positron emission tomography with 18F-fluorodeoxyglucose. They were subgrouped into the 1) pre-treatment, 2) post-treatment, 3) recurrence and 4) terminal patient groups. These subgroups were compared to the control group of 17 in-patients with benign diseases, using voxel-based Statistic Parametrical Mapping software (SPM). Results: Relative reduction in the regional cerebral metabolism was detected in the prefrontal and basolateral (inferolateral) prefrontal cortex, orbitofrontal cortex, anterior and posterior cingulate gyrus, insula, basal ganglia, hippocampus and thalamus in the pre-treatment group. The anterior and posterior cingulate gyri were hypometabolic only in the pre-treatment group. Hypometabolic areas were detected only in the basolateral prefrontal cortex, orbitofrontal cortex, ventral part of cingulate gyrus and insula in the post-treatment group. In the terminal group, the hypometabolic pattern seemed very close to that in the pre-treatment group. The results seemed to suggest that hypometabolic findings before treatments could reverse after treatments but became prominent again in terminal stages. These results do not contradict with previous epidemiological findings that high incidence of adjustment disorders was seen in earlier stages and more brain organic syndromes were seen in terminal stages. Conclusion: It could be speculated that decreased metabolism in early stages reflects state-dependent changes and that decreased metabolism in the terminal stages reflects organic brain damages, brain of cancer patients show a fluctuation in the regional metabolism. This finding might give a suggestion that functional imaging could be used as a supplementary method for psychological evaluation of patients with severe diseases.