Purpose: To compare (18)F-fluorocholine positron-emission tomography/computed tomography (PET/CT) with extended pelvic lymph node dissection (ePLND) for the detection of lymph node metastases in a large cohort of patients with high-risk prostate cancer.
Materials and methods: Patients with prostate-specific antigen levels between 20 and 99 ng/mL and/or Gleason score 8-10 cancers, planned for treatment with curative intent following a negative or inconclusive standard bone scan, were investigated with (18)F-fluorocholine PET/CT followed by an ePLND. None of the patients received hormonal therapy prior to these staging procedures. Results for PET/CT were compared on a per-patient basis with histopathology from ePLND. Sensitivity, specificity, positive and negative predictive values were calculated.
Results: PET/CT detected a total of 76 suspected lymph node metastases and four suspected bone metastases in 33 (29 %) of the 112 included patients. Of these, 35 suspected lymph node metastases, only within the anatomical template area of an ePLND, were found in 21 of the patients. Histopathology of the ePLND specimens detected 117 lymph node metastases in 48 (43 %) of the 112 patients. Per-patient sensitivity, specificity, positive and negative predictive values for (18)F-fluorocholine PET/CT for lymph node metastases within the ePLND template were 0.33, 0.92, 0.76 and 0.65, respectively. Only 11 patients had lymph nodes larger than 10 mm that would have been reported by CT alone.
Conclusions: (18)F-fluorocholine PET/CT detects lymph node metastases in a significant proportion of patients with high-risk prostate cancer with a high specificity, but low sensitivity.