1012 Evaluation of lymph node recurrent prostate cancer with integrated [11C]choline PET/CT in patients with PSA failure after radical prostatectomy: Validation by histological analysis

Abstract

INTRODUCTION AND OBJECTIVES: The aim of this study was to prospectively evaluate the accuracy of integrated [(11)C]choline-PET/CT in the diagnosis of lymph-node recurrence in patients previously treated with radical prostatectomy (RP) who experience PSA relapse. METHODS: The study included 71 patients with biochemical recurrence (BCR) and pathologic nodal [(11)C]choline-uptake at PET/CT scan suggestive of nodal recurrence. All patients were treated with either bilateral pelvic salvage lymph node dissection (sLND) alone (n 16; 22.5%) or with a combination of pelvic retroperitoneal sLND (n 55; 77.5%) between October 2002 and July 2011 at a single tertiary referral center. BCR was defined as a PSA value 0.2 ng/ml. All patients had complete clinical and pathological data, including PSA at surgery, number of lymph nodes removed, number of positive lymph nodes as well as laterality and site of nodal metastases at sLND. For the purpose of the study, LN sites were stratified in: right pelvic, left pelvic and retroperitoneal, respectively. We analyzed sensitivity, specificity, positive and negative predictive value as well as accuracy of the [(11)C]choline-PET/CT in predicting presence of nodal metastases at sLND. All the analyses were performed in the e overall patient population and after stratifying according to PSA (namely, 2 versus 2 ng/ml) and androgen deprivation therapy (ADT) status at sLND. RESULTS: The mean number of removed and positive nodes at sLND were 30.4 (median 29; range: 4-87) and 9.2 (range: 0-66), respectively. Fifty-nine out of the 71 patients (83%) with positive [(11)C]choline-PET/CT had histologically proven nodal metastases of PCa at sLND. A per-site based analysis showed that sensitivity, specificity, positive predictive value, negative predictive value and accuracy of [(11)C]choline-PET/CT in predicting nodal recurrence were 75.5%, 77.9%, 78.5%, 74.7%, and 76.6%, respectively. Table 1 shows the performance characteristics of [(11)C]choline-PET/CT after stratification according to ADT status and PSA values at sLND. CONCLUSIONS: [(11)C]Choline-PET/CT represents an accurate diagnostic tool for the detection of lymph-node metastases of clinical recurrent prostate cancer, regardless of ADT status at sLND.