PD23-08\u2003EVALUATION OF FLUCICLOVINE (FACBC) PET SCAN FOR STAGING HIGH-RISK PROSTATE CANCER BEFORE PRIMARY TREATMENT

Abstract

INTRODUCTION AND OBJECTIVES: The PET radiotracer [18F]-fluciclovine was recently approved by FDA and CMS for detection of metastases in the setting of recurrence after primary treatment for prostate cancer and is undergoing rapid adoption; however, its potential to improve staging and decisions prior to treatment for initial staging has not yet been characterized. We sought to evaluate the potential for fluciclovine-PET to enhance care decisions in the setting of newly diagnosed, high-risk prostate cancer, where standard imaging has suboptimal sensitivity for detecting metastases. METHODS: Patients with AUA defined high-risk or unfavorable intermediate-risk prostate cancer and clinically localized disease on CT and/or MRI and bone scan already scheduled for robot assisted radical prostatectomy with extended pelvic lymph node dissection (RARP-EPLND) were eligible for this IRB-approved trial. Patients underwent fluciclovine PET-CT according to study parameters. RARP-EPLND with anatomic lymph node packets sent individually was then performed. Histologic findings of metastatic lymph nodes in patients and within specific packets (left pelvic, right pelvic, presacral and non-regional) were then compared to the pre-surgery fluciclovine PET-CT findings to calculate sensitivity and specificity. RESULTS: 38 patients underwent fluciclovine PET-CT and 35 patients underwent surgery. Mean age was 61.7yrs, mean PSA was 24.4, and median Gleason score was 4+4. Fluciclovine PET-CT showed suspected extraprostatic disease in 15 patients (39.5%). Three patients were found to have extensive disease on fluciclovine PET-CT and determined to have metastatic disease (confirmed on biopsy, standard of care MRI for bone or clinical response to ADT) and therefore did not undergo surgery. Of the 35 patients undergoing surgery 18/35 (51.4%) had metastatic nodes on histology with fluciclovine PET detecting nodes in 10/18 (55.6%) of these patients for a calculated sensitivity of 61.9%, specificity of 88.2%, PPV of 86.7%, and NPV of 65.2%, with overall accuracy of 73.7%. Diagnostic performance at the lymph node packet level demonstrated a sensitivity of 62.2%, specificity 97.1%, PPV 88.5%, NPV 87.7%, and overall accuracy 87.9%. CONCLUSIONS: Fluciclovine PET-CT appears to be a valuable tool for pre-treatment staging of patients with high-risk prostate cancer with a high specificity for detection of metastatic lymph nodes. Fluciclovine PET-CT may help in decision-making for treatment options and help guide lymph node dissection during surgery. Source of Funding: NIH U01-CA113913-11