Regional cerebral glucose metabolism in patients with secondary depressive episodes after fatal pancreatic cancer diagnosis

Background: Secondary depression is common in the clinical oncology setting after pancreatic cancer diagnosis, following which the patients have to face the fact that they have a cancer with an extremely poor prognosis. However, the specific pathophysiology remains unclear. The present study examined the regional cerebral glucose metabolism using F18-fluorodeoxyglucose (F18-FDG) positron emission tomography (PET) in antidepressant-naïve pancreatic cancer patients with a depressive episode after their cancer diagnosis and before their cancer treatment. Methods: Regional cerebral glucose metabolism in pancreatic cancer patients without any antidepressant medication after the cancer diagnosis was measured with F18-FDG PET. A depressive episode after the cancer diagnosis was defined as including major and minor depressive episodes, and was diagnosed using the Diagnostic and Statistical Manual, Fourth Edition (DSM-IV). The prefrontal and limbic regions were the primary regions-of-interest, and an uncorrected value of p < 0.005 was used as significant. Results: Six of 21 pancreatic cancer patients were diagnosed as having a depressive episode. Significantly higher glucose metabolism in depressed patients was found in the subgenual anterior cingulate cortex (sACC) (uncorrected p = 0.002). Limitations: There was a small number of subjects, and there were no healthy controls. Conclusions: The higher metabolism in the sACC may be associated with the pathophysiology of secondary depressive episodes in patients following pancreatic cancer diagnosis.