¹⁸F-fluorocholine PET whole-body MRI in the staging of high-risk prostate cancer

OBJECTIVE. The purpose of this study was to determine whether integrated ¹⁸F-fluoro-choline (FCH) PET whole-body MRI (PET/WBMRI) depicts lymph node and distant metastases in patients with high-risk prostate cancer more frequently than does conventional staging. SUBJECTS AND METHODS. A prospective study included 58 patients with untreated high-risk prostate cancer. After conventional staging (CT and bone scintigraphy), patients underwent FCH PET/WBMRI (n = 10) or FCH PET/CT and WBMRI (n = 48). Metastatic sites and disease stage were recorded for each modality (conventional imaging, PET, WBMRI, and PET/WBMRI) and compared with a standard of reference (histopathologic examination, imaging, and clinical follow-up) and early clinical outcomes. RESULTS. In the detection of metastases, PET had significantly higher sensitivity (72/77 [93.5%]) than conventional imaging (49/77 [63.6%]; p < 0.001) and WBMRI (56/77 [72.7%]; p = 0.002). There was a trend toward improved detection with PET/WBMRI (77/77 [100%]) compared with PET alone (p = 0.059). For correct NM staging, PET and PET/WBMRI performed better than conventional imaging (p = 0.002) and WBMRI (p = 0.008). Twelve of 56 patients (21.4%) had early biochemical failure after radical treatment (median, 7 months; range, 1-20 months). This rate was higher for patients with M1a or M1b disease at PET/ WBMRI than for others, but this finding did not reach statistical significance (4/8 [50%] vs 8/48 [16.7%]; p = 0.055). CONCLUSION. In patients with high-risk prostate cancer, FCH PET and FCH PET/ WBMRI depict significantly more metastatic lesions than do conventional imaging and WBMRI. Stage determined with PET/WBMRI may correlate with early outcomes.