The impact of IV contrast enhanced 18F-FDG PET/CT on the staging of bladder cancer

Abstract

Objective: The aim of this retrospective study was to compare the diagnostic accuracies of conventional radiological imaging (CI) methods magnetic resonance imaging or computed tomography (MRI or CT) and intra venous (IV) contrast enhanced (CE) fluorine-18-fluorodeoxyglucose positron emission tomography/CT (¹⁸F-FDG PET/CT) for the staging of bladder cancer (BC).

Materials and methods: The ¹⁸F-FDG CE-PET/CT results of 35 consecutive patients with BC were analyzed. Diagnostic value of CE-PET/CT and CI are compared for their accuracy in revealing primary tumors, nodal-distant metastasis, and the final tumor staging. The imaging results were compared with the gold standard, including of histopathology and clinical follow-up. We also investigated the effect of maximum standardize uptake value (SUVmax) and lymph node metastasis on survival.

Results: The CE-PET/CT had a diagnostic accuracy of 89% (31/35), compared to 57% (19/35) for CI. The results of CE-PET/CT imaging lead to upstaging in 37% (13/35) patients compared to CI staging. For primary tumor detection, the sensitivity of CE-PET/CT was 97% (34/35). Contrast enhanced-PET/CT detected nodal metastases in 19 (54%) patients, whereas CI detected in 9 (26%) patients. Contrast enhanced-PET/CT detected distant metastases in 14 (40%) patients, while conventional methods showed distant metastases in 9 (26%) patients. Maximum SUV of primary tumor does not have a significant effect on survival, whereas the median survival time of patients without lymph node metastasis is longer than patients who have lymph node metastasis (P=0.038).

Conclusion: These data suggest that ¹⁸F-FDG CE-PET/CT had good diagnostic performance compared to conventional imaging for detecting primary tumor, nodal and distant metastasis in BC. Upstaging by CE-PET/CT changed the management of patients.