11C-Choline PET/CT and Bladder Cancer Lymph Node Metastasis Assessment With Pathological Specimens as Reference Standard

Aim: The aim of this study was to evaluate the potential role of C-11-choline-PET/CT in nodal assessment in patients with bladder cancer (BCa) using the pathological specimen as reference standard. Patients and Methods: Fifty-nine patients with proven BCa were retrospectively enrolled from April 2011 to January 2014 (mean [SD] age, 70.1 [9] years; range 49-85 years). Of 59 patients, 39 (staging group) were referred to C-11-choline-PET/CT for preoperative lymph node (LN) evaluation before radical cystectomy and extended pelvic LN dissection. Of the 59 patients, 29 (restaging group) had C-11-choline-PET/CT for suspected BCa relapse after primary radical surgery. In both groups, C-11-choline-PET/CT findings were correlated with histology. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated to assess C-11-choline-PET/CT feasibility in LN assessment. Age, TNM, histology, and previous chemotherapy were analyzed as additional predictive factors. Results: C-11-choline-PET/CT overall detection rate was 62.7% (37/59 patients). On a regional-based analysis, C-11-choline-PET/CT was considered positive for primary cancer and/or local relapse in bladder bed in 54.2% of the patients (32/59). Pathological LN uptake was reported in 23.7% of the patients (14/59) and systemic choline deposit (bone or lung) in 11.8% of the patients (7/59). Considering LN metastasis detection, compared with histological analysis, C-11-choline-PET/CT showed in the whole population a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 59%, 90%, 71%, 84%, and 81%, respectively. No other investigated factors reached statistical significance. Conclusions: C-11-choline-PET/CT may provide additional diagnostic information in preoperative nodal staging of patients with BCa and be considered a useful tool to restage patients with BCa suspected of relapse. Further studies are needed to assess if C-11'-choline-PET/CT could have an influence on survival of patients with BCa.