18F-Fluoromethylcholine-positron emission tomography/computed tomography for diagnosing bone and lymph node metastases in patients with intermediate- or high-risk prostate cancer.

BACKGROUND: The use of molecular imaging in staging of prostate cancer (PC) is debated. In patients with newly diagnosed PC we investigated the diagnostic value of 18F-flouromethylcholine positron emission tomography/computed tomography (18F-FCH-PET/CT) for the detection of bone and lymph node metastases compared to whole-body bone scintigraphy (WBS) with technetium-99-methylene diphosphonate (99mTc-MDP) and results of extended pelvic lymph node dissection, respectively. MATERIALS AND METHODS: Between January 2013 and April 2016, 143 patients, aged 49-83, mean 69, years with newly diagnosed PC and disease characteristics necessitating WBS underwent both WBS and 18F-FCH-PET/CT using magnetic resonance imaging as standard. Eighty of these patients underwent pelvic lymph node dissection as part of radical prostatectomy or prior to external beam radiation and in these results of 18F-FCH-PET/CT were compared to histologic findings. RESULTS: Bone metastases were detected in 8/143 patients and sensitivity and specificity of WBS were 37.5% and 85.2% versus 100.0% and 96.3% with 18F-FCH-PET/CT, P=0.63 and 0.002, respectively. Histologically confirmed metastases to regional lymph nodes were found in 25/80 patients. Suspicious choline uptake on PET/CT in pelvic lymph nodes was found in 35 patients. Sensitivity, specificity, PPV, NPV and accuracy of 18F-FCH-PET/CT in detection of lymph node metastases were 62.5%, 69.6%, 46.9%, 81.3% and 67.5%, respectively. CONCLUSIONS: Findings in this study suggested that 18F-FCH-PET/CT is a more sensitive and specific method for detection of bone metastases from PC than WBS and could potentially reduce the need for confirmatory imaging if used instead of WBS. However, 18F-FCH-PET/CT performs sub-optimally in pre-operative staging of lymph node metastases in patients undergoing extended pelvic lymph node dissection.