BACKGROUND: Psychological and psychiatric aspects of cancer patients havenot been studied well in terms of functional neuroimaging. The aim of this pilot study was to investigatethe 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 diseaseswas studied by positron emission tomography with 18F-fluorodeoxyglucose. They were subgrouped into the1) pre-treatment, 2) post-treatment, 3) recurrence and 4) terminal patient groups. These subgroups werecompared to the control group of 17 in-patients with benign diseases, using voxel-based Statistic ParametricalMapping software (SPM).
RESULTS: Relative reduction in the regional cerebral metabolism was detectedin the prefrontal and basolateral (inferolateral) prefrontal cortex, orbitofrontal cortex, anterior andposterior 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. Hypometabolicareas were detected only in the basolateral prefrontal cortex, orbitofrontal cortex, ventral part ofcingulate gyrus and insula in the post-treatment group. In the terminal group, the hypometabolic patternseemed very close to that in the pre-treatment group. The results seemed to suggest that hypometabolicfindings 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 adjustmentdisorders 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 andthat decreased metabolism in the terminal stages reflects organic brain damages. brain of cancer patientsshow a fluctuation in the regional metabolism. This finding might give a suggestion that functional imagingcould be used as a supplementary method for psychological evaluation of patients with severe diseases.

Keywords: cerebral glucose metabolism, cancer patients, PET