Early changes in brain FDG metabolism during anticancer therapy in patients with pharyngeal cancer

The current study aimed to evaluate whether therapy-related changes occurred in brain metabolism at an earlier stage during the course of anticancer therapy.

We recruited 14 non-diabetic male patients with newly diagnosed pharyngeal squamous cell carcinoma. We analyzed the patients' serial brain FDG PET/CT scans by SPM8 to establish whether any therapy-related changes had occurred in brain FDG metabolism, either during or after the course of therapy.

Decreased metabolism was noted during the anticancer therapy, displaying a symmetric pattern involving bilateral basal ganglia and bilateral occipital lobes. The decrease in FDG metabolism in these regions persisted after the anticancer therapy had terminated. However, relative recovery of the metabolism was noted in the bilateral occipital lobes, whereas further deterioration was noted in bilateral basal ganglia.

The current study revealed that unappreciable changes in brain metabolism can occur during the early course of anticancer therapy, and persist even after therapy has terminated. Although the exact mechanism remains unclear, these changes may be related to the systemic effects of chemotherapy or radiotherapy as well as subclinical cancer-related depressive or adjustment mood disorder.