LOS ANGELES — Prostate-specific membrane antigen (PSMA) ligands offer a strategy to develop prostate-specific positron emission tomography tracers, which can significantly heighten the accuracy of systemic prostate cancer imaging, according to a new study.
The report in Advances in Radiation Oncology focused on the effect of 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL) positron emission tomography (PET)-computed tomography (CT) on staging/treatment recommendations of previously untreated prostate cancer.1
The prospective single center single arm imaging trial was conducted at the VA Greater Los Angeles Healthcare System. It focused on the frequency of patients upstaged to M1 disease (primary endpoint) and the frequency of patients with change in treatment recommendations (secondary endpoint). The authors from the David Geffen School of Medicine at UCLA and the Los Angeles VAMC tout their study as the first on prostate-specific membrane antigen PET-CT exclusive to U.S. veterans.
Eligible for the study were veterans with Gleason ≥4 + 3, clinical stage ≥T2c, or prostate-specific antigen >10 ng/mL Patients underwent conventional imaging (99mTc-methyl diphosphonate bone scan or 18F-NaF PET-CT; and pelvic CT or pelvic magnetic resonance imaging) in addition to 18F-DCFPyL PET-CT. Researchers tracked the effect of 18F-DCFPyL PET-CT on treatment change by applying prespecified treatment recommendations based on National Comprehensive Cancer Network guidelines and modern clinical practice.
Overall, 100 patients underwent 18F-DCFPyL PET-CT. Results indicate that 19 out of 84 (23%) patients initially thought to be nonmetastatic were upstaged to M1. At the same time, half the patients initially thought to have M1 disease were downstaged to M0. In total, 39% of the patients had an alteration in prespecified treatment recommendations, including change of radiation therapy volume/dose in 39% and staring abiraterone in 22%.
“Incorporation of 18F-DCFPyL PET-CT into the initial conventional imaging workup for prostate cancer can substantially affect staging/treatment recommendations,” the authors concluded.
That’s important, they pointed out, because treatment recommendations for patients with newly diagnosed prostate cancer have markedly evolved. “Given these significant developments in the treatment landscape of de novo prostate cancer, the need for accurate upfront staging is absolutely critical,” researchers added.
- Parikh NR, Tsai S, Bennett C, Lewis M, et. Al. The Impact of 18F-DCFPyL PET-CT Imaging on Initial Staging, Radiation, and Systemic Therapy Treatment Recommendations for Veterans With Aggressive Prostate Cancer. Adv Radiat Oncol. 2020 Sep 9;5(6):1364-1369. doi: 10.1016/j.adro.2020.08.014. PMID: 33305100; PMCID: PMC7718503.