A study from the University of Alberta has revealed that PET/CT (Positron Emission Tomography/Computed Tomography) imaging using a new tracing agent is significantly more accurate in determining the extent of prostate cancer compared to the current standard MRI (Magnetic Resonance Imaging) for intermediate and high-risk cases.
Published recently in the journal JAMA Oncology, the research indicates that the new test accurately predicted the location and margin of tumours in 45 percent of cases, nearly doubling the 28 percent accuracy rate of MRI.
“This is very important because we make a lot of treatment decisions based on where the cancer is in the prostate,” explained Adam Kinnaird, assistant professor of surgery, adjunct assistant professor of oncology, and the Frank and Carla Sojonky Chair in Prostate Cancer Research at the Cancer Research Institute of Northern Alberta.
“If you’re having your prostate removed and the cancer is sneaking outside of the prostate, then we go a little bit wider with our treatment margins so we don’t leave any cancer behind. If you’re having radiation to your prostate, the radiation oncologist sometimes provides a boost to the centre of the cancer for better control,” Kinnaird added. “This imaging test gives us a better degree of accuracy in terms of where exactly we need to treat.”
The new test involves injecting a radioactive prostate-tumour-specific tracer called 18F-PSMA-1007 into the blood, then tracking it using a combination of positron-emitting tomography and computerized tomography. Previous studies using other tracing agents in PET/CT scans were not as effective, Kinnaird noted.
The study involved 134 Alberta men scheduled for radical prostatectomy, with both PET/CT and MRI tests performed within two weeks of each other. The accuracy of the tests was then compared to the actual tumour sizes and locations found during surgery.
“This clinical trial has great implications for clinical practice worldwide,” Kinnaird stated, anticipating that PET/CT scans with the new tracer will become the gold standard. Despite a small dose of radiation exposure, no patients experienced adverse reactions. Kinnaird expects this test could replace other CT and bone scans currently required for prostate cancer patients, reducing hospital visits, wait times, and radiation exposure.
“It will be very exciting if you can get more accurate information and replace three tests with one test,” said graduate research fellow Patrick Albers, a co-author of the study.
The promising results have already led to another clinical trial to determine whether PET/CT scans can guide ablation procedures to kill cancer cells within the prostate.
While awaiting Health Canada approval, the new imaging agent is offered at a few treatment centres. In the meantime, the Alberta government has allocated $3 million for 2,000 men to receive the new scans.
In related research, Kinnaird’s team found that black men with prostate cancer in Alberta have similar outcomes to other men despite being diagnosed on average two years earlier. The study recommends routine screening for black men starting at age 45. The findings challenge the notion that biological factors alone explain the higher incidence of prostate cancer among black men in the U.S. and U.K., suggesting that socioeconomic factors such as racism, poverty, and healthcare access play a significant role.
©
