Purpose: The purpose of this study was to assess the diagnostic accuracy of 18F-fluorodeoxyglucose with positron emission tomography and computed tomography (FDG-PET-CT) to predict nodal metastases in patients with bladder cancer (BC) scheduled to undergo radical cystectomy (RC).
Methods: We retrospectively reviewed records of patients diagnosed with BC and scheduled to undergo RC at our center from January 2011 through February 2015, who also underwent FDG-PET-CT at the time of diagnosis. All patients underwent RC and an extended pelvic lymph node dissection as the reference standard. The primary endpoints were the sensitivity, specificity and overall accuracy of FDG-PET-CT in detecting lymph node metastasis. We also examined its accuracy in identifying distant metastasis. In addition, we conducted a protocol-driven systematic review and meta-analysis of accuracy of FDG-PET-CT for preoperative staging of BC, as compared to CT alone, as reported in individual studies. To assess the methodological quality of eligible studies, we used the QUADAS-2 tool (a revised tool for the Quality Assessment of Diagnostic Accuracy Studies) and pooled diagnostic accuracy measures using Meta-DiSc statistical software.
Results: For detecting nodal metastases in 78 patients, the sensitivity of FDG-PET-CT was 0.56 (95 % CI 0.29-0.80) and the specificity, 0.98 (95 % CI 0.91-1.00). Pooled sensitivity and specificity for detecting lymph node metastasis were 0.57 and 0.95, respectively. Positive likelihood ratio was 9.02. All lesions that were suspicious for distant metastasis were found to be positive on biopsy.
Conclusion: FDG-PET-CT was more accurate than CT alone in staging BC in patients undergoing surgery. Standardization of FDG-PET-CT protocol and cost-effectiveness analysis are required before widespread implementation of this technology.
Keywords: Bladder cancer; Lymph nodes; Positron emission tomography; Preoperative staging; Urinary bladder neoplasms.