18F-choline PET/CT for the assesment of pelvic lymph node metastases in high-risk prostate cancer patients.

61 Background: Assesment of pelvic lymph node involvement is a major dilemma due to poor diagnostic accuracy of conventional imaging such as computed tomography of the pelvis or magnetic resonance of the pelvis. Recently incorporation of new tools such as 18F-choline PET/CT address this issue, although there are few studies in this set of patients. To evaluate the 18-choline PET/CT diagnostic accuracy for staging of pelvic lymph node involvement in patients with high risk prostate cancer. Methods: Patients with diagnosis of high risk prostate cancer according to D’Amico risk assessment criteria where staged with a 18F-choline PET/CT prior to treatment with retropubic radical prostatectomy plus superextended bilateral lymph node dissection at our institution. 18F-choline PET/CT was compared with the results of pathological analisys of lymph nodes. We calculated sensitivity, specificity, positive and negative predictive value for 18F-choline PET/CT. Results: Between January 2012 and August 2014 a total of 36 patients met the following inclusion criteria: diagnosis of high prostate cancer (cT2c or more or PSA above 20 ng/ml or a gleason score 8-10), good performance status (ECOG 0-2) and a 18F-choline PET/CT as a preoperative staging procedure. Sensitivity, specificity, positive and negative predictive value were 64%, 92%, 77% and 85% respectively. Conclusions: 18F-choline PET/CT is a non invasive procedure that provides good information regarding pelvic lymph node involvement status that is better than the results of other techniques in published series, with a higher sensitivity in our group of patients. It is highly specific which means there is a very good chance that a patient with a normal study does not have lymph node metastases when analyzed.