GU Cancers Symposium 2020: Use of Novel PET/CT Radiotracer in Staging High-Risk Prostate Cancer
Posted: Friday, February 21, 2020
Regional or distant metastatic lesions of prostate cancer were detected using a novel prostate-specific membrane antigen (PSMA)-targeted radiopharmaceutical for positron-emission tomography/computed tomography (PET/CT)—[18F]-DCFPyl. Frederic Pouliot, MD, PhD, of Centre Hospitalier Universitaire de Québec-Université Laval, Canada, presented these findings on behalf of his colleagues at the 2020 Genitourinary (GU) Cancers Symposium in San Francisco (Abstract 9).
“These results suggest the potential utility of [18F]-DCFPyL PET/CT in the staging of men with newly diagnosed high-risk prostate cancer to develop optimized treatment paradigms,” concluded the authors.
This study recruited 252 men with high-risk prostate cancer who were to undergo radical prostatectomy with lymphadenectomy. Patients were administered 9 mCi of [18F]-DCFPyl 1 to 2 hours before PET/CT, and the radiotracer’s detection rates were systematically analyzed using TNM staging. Lesions were categorized as being in the prostate (T), pelvic lymph nodes (N), extrapelvic lymph nodes (M1a), bone (M1b), and other visceral organs or soft tissue (M1C) by blinded, independent readers.
At the study outset, 97% of patients had no known nodal disease, and 99% had no known metastatic disease based on standard cross-sectional imaging. Among this cohort, the radiotracer staged 14.7% of patients with N1 disease and 10.7% of patients with M1 disease (1 as M1a, 23 as M1b, and 3 as M1c). Taken together, use of [18F]-DCFPyl upstaged 22% of patients to N1 or M1 disease. The positive predictive value of the [18F]-DCFPyl PET/CT test based on histopathologic validation for pelvic lymph nodes was 86.7%. One patient underwent a biopsy of a radiotracer-detected M1 finding, and histopathology confirmed the diagnosis of metastasis to the spine to be a true positive result.
Disclosure: The study authors reported no conflicts of interest.
