275 Background: Radical cystectomy with extended pelvic lymphadenectomy (EPLA) is the treatment of choice for muscle-invasive bladder cancer. For preoperative staging computed tomography and magnetic resonance imaging of the abdomen and the small pelvis are most commonly used in daily routine.Since the aforementioned methods, have a low sensitivity to detect local lymph node metastasis (LNM) we have prospectively evaluated the role of FDG – PET/CT for locoregional staging. Methods: In 27 patients (n = 27) with known invasive urothelial carcinoma or squamous cell carcinoma of the bladder a staging FDG – PET - CT was performed 1-2 days prior to radical cystectomy with EPLA. Subsequently, the results of the histopathological work-up of lymph node specimens and their anatomical localisations were correlated to the FDG-PET/CT findings. Total of 452 lymph nodes were removed, on average ≈ 16.7 per patient. Results: In 3/27 (11.1%) patients LNM were detected in histopathology. 2 patients showed one positive lymph node, 1 patient had two LNM. In two of these patients, the FDG-PET/CT showed an increased enrichment of FDG in projection to the corresponding histologically positive LN. One false negative and one false positive result of FDG-PET/CT were found. Calculated based on the patient population, the following statistics were calculated: Sensitivity (SENS) 66%, specificity (SPEC) 95.8%, positive predictive value (PPV) 66%, negative predictive value (NPV) 95.8%. Related to the absolute number of LN (n = 452), the following numbers were calculated: SENS 75% SPEC 98.7, PPV 37.5%, NPV 99.7%. Conclusions: To date, few studies have been conducted with regard to FDG-PET/CT and its role in locoregional staging. The reported specificity and NPV was between 86% and 100%, sensitivity and PPV were between 50% and 100%. Our results demonstrate specificity and NPV values of larger than 90% and make FDG-PET/CT a valuable staging tool to potentially identify patients with negative nodes in whom EPLA could be safely ommitted. Curently, routine use of PET CT scans can not be recommended and it is currently tested in a prospective multicenter study including a larger patient cohort.
Is [F-18]-fluorodeoxyglucose FDG-PET/CT better than ct alone for the preoperative lymph node staging of muscle invasive bladder cancer?
