Clinical impact of PSMA-based 18F-DCFBC PET/CT imaging in patients with biochemically recurrent prostate cancer after primary local therapy.

The purpose of our study was to assess 18F-DCFBC PET/CT, a PSMA targeted PET agent, for lesion detection and clinical management of biochemical relapse in prostate cancer patients after primary treatment.

This is a prospective IRB-approved study of 68 patients with documented biochemical recurrence after primary local therapy consisting of radical prostatectomy (n = 50), post radiation therapy (n = 9) or both (n = 9), with negative conventional imaging. All 68 patients underwent whole-body 18F-DCFBC PET/CT, and 62 also underwent mpMRI within one month. Lesion detection with 18F-DCFBC was correlated with mpMRI findings and pre-scan PSA levels. The impact of 18F-DCFBC PET/CT on clinical management and treatment decisions was established after 6 months' patient clinical follow-up.

Forty-one patients (60.3%) showed at least one positive 18F-DCFBC lesion, for a total of 79 lesions, 30 in the prostate bed, 39 in lymph nodes, and ten in distant sites. Tumor recurrence was confirmed by either biopsy (13/41 pts), serial CT/MRI (8/41) or clinical follow-up (15/41); there was no confirmation in five patients, who continue to be observed. The 18F-DCFBC and mpMRI findings were concordant in 39 lesions (49.4%), and discordant in 40 lesions (50.6%); the majority (n = 32/40) of the latter occurring because the recurrence was located outside the mpMRI field of view. 18F-DCFBC PET positivity rates correlated with PSA values and 15%, 46%, 83%, and 77% were seen in patients with PSA values <0.5, 0.5 to <1.0, 1.0 to <2.0, and ≥2.0 ng/mL, respectively. The optimal cut-off PSA value to predict a positive 18F-DCFBC scan was 0.78 ng/mL (AUC = 0.764). A change in clinical management occurred in 51.2% (21/41) of patients with a positive 18F-DCFBC result, generally characterized by starting a new treatment in 19 patients or changing the treatment plan in two patients.

18F-DCFBC detects recurrences in 60.3% of a population of patients with biochemical recurrence, but results are dependent on PSA levels. Above a threshold PSA value of 0.78 ng/mL, 18F-DCFBC was able to identify recurrence with high reliability. Positive 18F-DCFBC PET imaging led clinicians to change treatment strategy in 51.2% of patients.

European journal of nuclear medicine and molecular imaging. 2017 Sep 11 [Epub]

Esther Mena, Maria L Lindenberg, Joanna H Shih, Stephen Adler, Stephanie Harmon, Ethan Bergvall, Deborah Citrin, William Dahut, Anita T Ton, Yolanda McKinney, Juanita Weaver, Philip Eclarinal, Alicia Forest, George Afari, Sibaprasad Bhattacharyya, Ronnie C Mease, Maria J Merino, Peter Pinto, Bradford J Wood, Paula Jacobs, Martin G Pomper, Peter L Choyke, Baris Turkbey

Molecular Imaging Program, National Cancer Institute, NIH, Bethesda, MD, USA. ., Molecular Imaging Program, National Cancer Institute, NIH, Bethesda, MD, USA., Division of Cancer treatment and Diagnosis: Biometric Research Program, National Cancer Institute, NIH, Bethesda, MD, USA., Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research, Inc., National Cancer Institute, Campus at Frederick, Frederick, MD, USA., Radiation Oncology Branch, Center for Cancer Research. National Cancer Institute, NIH, Bethesda, MD, USA., Genitourinary Malignancies Branch, National Cancer Institute, NIH, Bethesda, MD, USA., Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD, USA., Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA., Laboratory of Pathology, NCI, NIH, Bethesda, MD, USA., Urologic Oncology Branch, National Cancer Institute, NIH, Bethesda, MD, USA., Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Cancer Institute, NIH, Bethesda, MD, USA., Cancer Imaging Program, National Cancer Institute, NIH, Rockville, MD, USA.