Pilot Study of [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET)/Magnetic Resonance Imaging (MRI) for Staging of Muscle-invasive Bladder Cancer (MIBC)

• Published in: Clinical genitourinary cancer 2020-10, Vol.18 (5), p.378-386.e1
• Main Authors: Eulitt, Patrick J., Altun, Ersan, Sheikh, Arif, Wong, Terence Z., Woods, Michael E., Rose, Tracy L., Wallen, Eric M., Pruthi, Raj S., Smith, Angela B., Nielsen, Matthew E., Whang, Young E., Kim, William Y., Godley, Paul A., Basch, Ethan M., David, Grace U., Ramirez, Juanita, Deal, Allison M., Rathmell, W. Kimryn, Chen, Ronald C., Bjurlin, Marc A., Lin, Weili, Lee, Joseph K., Milowsky, Matthew I.
• Format: Article
• Language: English
• Subjects: Novel imaging modality; Preoperative staging; Surgical pathology; Test characteristics; Urothelial carcinoma
• ISSN: 1558-7673; 1938-0682
• DOI: 10.1016/j.clgc.2020.02.008

Computed tomography (CT) has limited diagnostic accuracy for staging of muscle-invasive bladder cancer (MIBC). [18F] Fluorodeoxyglucose positron emission tomography (FDG-PET)/magnetic resonance imaging (MRI) is a novel imaging modality incorporating functional imaging with improved soft tissue characterization. This pilot study evaluated the use of preoperative FDG-PET/MRI for staging of MIBC. Twenty-one patients with MIBC with planned radical cystectomy were enrolled. Two teams of radiologists reviewed FDG-PET/MRI scans to determine: (1) presence of primary bladder tumor; and (2) lymph node involvement and distant metastases. FDG-PET/MRI was compared with cystectomy pathology and computed tomography (CT). Eighteen patients were included in the final analysis, most (72.2%) of whom received neoadjuvant chemotherapy. Final pathology revealed 10 (56%) patients with muscle invasion and only 3 (17%) patients with lymph node involvement. Clustered analysis of FDG-PET/MRI radiology team reads revealed a sensitivity of 0.80 and a specificity of 0.56 for detection of the primary tumor with a sensitivity of 0 and a specificity of 1.00 for detection of lymph node involvement when compared with cystectomy pathology. CT imaging demonstrated similar rates in evaluation of the primary tumor (sensitivity, 0.91; specificity, 0.43) and lymph node involvement (sensitivity, 0; specificity, 0.93) when compared with pathology. This pilot single-institution experience of FDG-PET/MRI for preoperative staging of MIBC performed similar to CT for the detection of the primary tumor; however, the determination of lymph node status was limited by few patients with true pathologic lymph node involvement. Further studies are needed to evaluate the potential role for FDG-PET/MRI in the staging of MIBC. In this pilot study, preoperative staging with [18F] fluorodeoxyglucose-positron emission tomography/magnetic resonance imaging in muscle-invasive bladder cancer detected the primary bladder tumor; however, the determination of lymph node status was limited by few patients with pathologic lymph node involvement. Additional studies are needed to evaluate the potential role for [18F] fluorodeoxyglucose-positron emission tomography/magnetic resonance imaging in the staging of bladder cancer.