Use of fluciclovine (18F) positron emission tomography/computed tomography (PET/CT) in addition to conventional imaging to guide radiation therapy for men with recurrent prostate cancer (PCa) following radical prostatectomy is associated with improved outcomes compared with conventional imaging alone, investigators reported during the American Society for Radiation Oncology (ASTRO) virtual annual meeting.
The finding is from the EMPIRE-1 (Emory Molecular Prostate Imaging for Radiotherapy Enhancement) trial, the first randomized trial comparing how radiotherapy decisions guided by the 2 modalities affect outcomes among men with post-prostatectomy PCa recurrence. Investigators randomly assigned 165 patients to receive external beam radiation therapy (EBRT) based on conventional imaging (bone scan plus CT or magnetic resonance imaging [MRI] of the abdomen and pelvis) or conventional imaging plus fluciclovine PET/CT.
To be enrolled in the study, patients needed to have detectable PSA following radical prostatectomy, negative bone scans, and no extra-pelvic metastases found on CT or MRI scans of the abdomen or pelvis. The treatment arms were balanced with respect to age, race, PSA level, androgen deprivation therapy use, and pathologic characteristics.
The median follow-up duration was about 2.5 years overall and 3.0 years for the failure-free patients. A total of 125 patients had a minimum follow-up duration of 3 years. The 3-year failure-free survival rate, the study’s primary endpoint, was significantly greater in the PET/CT group than in the control group (75.5% vs 63.0%), co-principal investigator Ashesh B. Jani, MD, of the Winship Cancer Institute at Emory University School of Medicine in Atlanta, Georgia, reported in a late-breaking abstract session. The 4-year failure-free survival rate also was significantly greater in the PET/CT group (75.5% vs 51.2%). On multivariable analysis, patients in arm 2 were twice as likely to have failure-free survival compared with controls.
“What this research has found is that integrating advanced molecular imaging into the treatment planning process allows us to do a better job of selecting patients for radiation therapy, guiding radiation treatment decisions and planning and ultimately, keeping patients’ cancer under control,” Dr Jani said in an ASTRO press release.
Radiation treatment decisions for the PET/CT group were determined strictly by PET. Patients with extra-pelvic fluciclovine uptake received no radiation, whereas those with pelvic uptake received radiation to the pelvis and prostate bed, according to the investigators. Uptake only at the prostate bed led to radiation treatment directed at that site. Radiation also was directed to the prostate bed when no uptake was detected anywhere.
Toxicity was similar in both study arms, suggesting the PET-guided treatment was well tolerated, the investigators reported.
Jani A, Schreibmann E, Goyal S, et al. Initial report of a randomized trial comparing conventional- vs conventional plus fluciclovine (18F) PET/CT imaging-guided post-prostatectomy radiotherapy for prostate cancer. Presented at: ASTRO 2020 virtual annual meeting, October 23-29, 2020. Abstract LBA 1.