PET Molecular Imaging Improves Disease-Free Survival in Prostate Cancer Treatment

Adding positron emission tomography (PET) molecular imaging to conventional cancer screening guided treatment decisions that led to improved disease-free survival (DFS) among men with recurrent prostate cancer, according to findings presented at the virtual American Society for Radiation Oncology 2020 Annual Meeting.

The phase II/III EMPIRE-1 (Emory Molecular Prostate Imaging for Radiotherapy Enhancement) trial enrolled 165 patients with recurrent prostate cancer following prostatectomy. Participants were randomized to either radiation therapy based on conventional screening or treatment based on imaging with the fluciclovine PET radiotracer, a molecular imaging agent. The primary endpoint was failure rate at three years. The main goal of the investigation was to use the advanced molecular imaging to improve post-prostatectomy decision making regarding whether to deliver radiotherapy and optimize where radiation is received.

The three-year DFS rate was 75.5% among patients who underwent the molecular imaging compared with 63% among those who received conventional imaging alone (P=0.003). The DFS benefit persisted at four years in the PET scan group (75.5% vs. 51.2%; P<0.001). There were no significant differences in severe genitourinary or gastrointestinal adverse effects between the two groups.

“At three years, the group getting treatment guided by PET fluciclovine had a 12% better cancer control rate, and this persisted at four years as well, with a 24% improvement,” said study leader Ashesh B. Jani, MD, in a press release. “We think the improvement was seen because the novel PET allowed for better selection of patients for radiation, better treatment decisions, and better radiation target design.”

The same investigators will conduct a second trial, EMPIRE-2, to assess the efficacy a new type of advanced molecular imaging, prostate-specific membrane antigen PET. The novel radiotracer targets a receptor on the surface of prostate cancer cells and could potentially be even more effective than fluciclovine in guiding treatment decisions for patients with prostate cancer.