Diagnostic accuracy of (11)C-choline PET/CT in preoperative lymph node staging of bladder cancer: a systematic comparison with contrast-enhanced CT and histologic findings.

Aim: The aim of this study was to evaluate the role of C-choline PET/CT in the preoperative evaluation of the nodal involvement of patients with bladder carcinoma (BC) suitable for radical cystectomy and extended pelvic lymph node dissection in comparison with contrast-enhanced CT (CECT) using the pathologic specimen as reference standard.
Patients and Methods: Twenty-six consecutive patients (69.5 ± 9.3 years; range, 49-84) with histologically proven transitional cell BC were treated with radical cystectomy and pelvic lymph node dissection and were enrolled from April 2011 to January 2013. In all patients, paravesical, internal, eternal, and common iliac nodes as well as obturatory, presacral, preaortic, and precaval lymph nodes (LNs) were dissected up to the origin of the inferior mesentery artery. The areas of the LN dissection were grouped as follow: region A included preaortic and precaval LNs; region B included paravesical, common, internal and external iliac, obturatory, and presacral LNs in the right pelvis; region C included paravesical, common, internal and external iliac, obturatory, and presacral LNs in the left pelvis. C-choline PET/CT and abdominal CECT were used to assess the presence of lymph node metastases on a per patient, region, and lesion analysis using the results of surgical specimens obtained at operation as criterion standard.
Results: Seven of 26 patients (26.9%) showed nodal metastases at pathologic analysis. Overall, 844 LNs were evaluated, and 38 of them (4.5%) showed metastatic involvement. On a patient-based analysis, C-choline PET/CT showed a sensitivity of 42% and specificity of 84%, whereas, CECT showed a sensitivity of 14% and specificity of 89%. On a region-based analysis, C-choline PET/CT showed a sensitivity of 11% and specificity of 82%, whereas CECT showed a sensitivity of 5% and specificity of 80%. On a lesion (LN)-based analysis, C-choline PET/CT showed a sensitivity of 10% and specificity of 64%, whereas CECT showed a sensitivity of 2% and specificity of 63%.
Conclusions: C-choline PET/CT could provide additional diagnostic information in preoperative nodal staging of patients with invasive BC in comparison with CECT. A study with a larger population should determine if C-choline PET/CT could be recommended as a routine technique in high-risk patients with BC.