Depressive state and regional cerebral activity in cancer patients - A preliminary study

Background: The aim of this study was to investigate influences of depressive states, chemotherapy and existence of remaining tumors on the regional brain activity of cancer patients. Material and methods: Positron emission tomography with 18F-fluorodeoxyglucose was performed on 21 patients with various types of cancer. Their brain images were compared to 10 age- and gender-matched control data using statistical parametric mapping (SPM). The patients were subgrouped into the with and without depression based on the scores on Zung's self-rating depression scale (SDS), with and without previous chemotherapy, and with and without existence of remaining tumors. Results: Significant metabolic reduction was detected in the cingulate gyrus, prefrontal, dorsolateral prefrontal, temporoparietal cortices and basal ganglia in cancer patients. These findings were close to known lesions of major depression. Intra-group comparisons showed that these hypometabolic findings were associated with the depth of depressive state. Influences of chemotherapy and remaining tumors on the cerebral cortex seemed to be weaker than that of psychological factors. Conclusion: The present pilot study suggests that frontal hypoactivity commonly seen in cancer patients is likely to be associated with depression rather than chemotherapy or remaining tumors. A brain mapping technique might be useful in evaluating neuropsychiatric problems in cancer patients.