Prospective comparison of computed tomography, diffusion-weighted magnetic resonance imaging and [11C]choline positron emission tomography/computed tomography for preoperative lymph node staging in prostate cancer patients.

PURPOSE: The aim of this study was to prospectively compare diffusion-weighted magnetic resonance imaging (DWI) and [(11)C]choline positron emission tomography/computed tomography (PET/CT) with computed tomography (CT) for preoperative lymph node (LN) staging in prostate cancer (PCa) patients.

METHODS: Between June 2010 and May 2012, CT, DWI and [(11)C]choline PET/CT were performed preoperatively in 33 intermediate- and high-risk PCa patients undergoing radical prostatectomy (RP) and extended pelvic lymph node dissection (ePLND) including obturator fossa and internal, external and common iliac fields. Patient- and field-based performance characteristics for all three imaging techniques based on histopathological results are reported. Imaging techniques were compared by means of the area under the curve (AUC).

RESULTS: LN metastases were detected in 92 of 1,012 (9%) LNs from 14 of 33 (42%) patients. On patient-based analysis, sensitivity, specificity and accuracy for CT were 57, 68 and 64%, respectively, for DWI were 57, 79 and 70%, respectively, and for [(11)C]choline PET/CT were 57, 90 and 76%, respectively. On field-based analysis, these numbers for CT were 47, 94 and 88%, respectively, for DWI were 56, 97 and 92%, respectively, and for [(11)C]choline PET/CT were 62, 96 and 92%, respectively. Neither DWI nor [(11)C]choline PET/CT performed significantly better than CT on pairwise comparison of patient- and field-based results.

CONCLUSION: All three imaging techniques exhibit a rather low sensitivity with less than two thirds of LN metastases being detected on patient- and field-based analysis. Overall diagnostic efficacy did not differ significantly between imaging techniques, whereas distinct performance characteristics, esp. patient-based specificity, were best for [(11)C]choline PET/CT followed by DWI and CT.