[F-18]-Fluorodeoxyglucose PET and PET-CT in diagnostic imaging evaluation of locally recurrent and metastatic bladder transitional cell carcinoma.

Background: Little data is available on the utility of positron emission tomography (PET) and positron emission tomography-computed tomography (PET-CT) with [F-18]-fluorodeoxyglucose (FDG) in patients with bladder cancer. We retrospectively assessed the diagnostic utility of dedicated PET and hybrid PET-CT scans with [F-18]-FDG in the imaging evaluation of recurrent and metastatic bladder transitional cell carcinoma.

Methods: The study group included 35 patients who were previously treated for the primary disease. We performed PET in 17 patients and 23 PET-CT scans in 18 patients. Diagnostic validation was by biopsy in 1 patient and clinical and radiological follow-up for up to 5 years in the remaining patients.

Results: PET and CT were true negative (TN) in 12 patients and true positive (TP) in 19 patients. In 4 patients in this group, both locally recurrent pelvic mass and distant metastases were demonstrated, while in 3 of these patients, unsuspected skeletal and/or nodal metastases were detected by PET-CT and these patients received additional courses of chemotherapy. PET was discordant with CT in 4 patients. PET was negative in 2 of these patients, while post-chemotherapy CT showed enlarged nodes that were determined to represent successfully treated disease. In another patient, a hypometabolic soft-tissue mass was considered to represent a scar, and a wait-and-watch strategy was pursued. In the remaining patient, PET showed random hypermetabolic osseous lesions that represented early marrow metastatic infiltration. The combined diagnostic information provided by PET-CT affected the clinical management in 17% of patients.

Conclusion: FDG PET and PET-CT scanning may improve the imaging evaluation of patients with recurrent and metastatic bladder cancer.