Researchers found that MRI scans, the current gold standard, can still detect prostate cancer more accurately than the newer, prostate-specific -PSMA PET/CT scanning technique.
The findings were presented at the European Association of Urology’s annual congress (EAU22).
Prostate-specific membrane antigen (PSMA) PET/CT scans, approved by the US FDA in 2020, use a radioactive dye to highlight areas of PSMA, which is overexpressed on the surface of prostate cancer cells. Presently, these scans are used to manage prostate cancer, as they can accurately measure the progression or recurrence of the disease. The researchers set out to find if they could be used to diagnose prostate cancer as well.
The PEDAL trial recruited 240 patients at risk of prostate cancer, with each patient given both an MRI scan and a PSMA PET/CT scan. If imaging suggested the presence of prostate cancer, a biopsy was performed by the patient’s urologist.
The MRI scans picked up abnormalities in 141 patients, while the PSMA PET/CT scans picked up abnormalities in 198 patients. A total of 181 patients (75%) underwent a prostate biopsy, and subsequently 82 of those patients were found to have clinically significant prostate cancer.
The MRI scans were significantly more accurate at detecting any grade of prostate cancer than the PSMA PET scans.
The research team was led by Associate Professor Lih-Ming Wong, who explained: “Our analysis found that MRI scans were better than PSMA-PET for detecting any grade of prostate cancer. When we looked only at clinically significant prostate cancers, there was no difference in accuracy. As this study is one of the first to explore using PSMA-PET to diagnose cancer within the prostate, we are still learning and adjusting how to improve using PSMA-PET in this setting.
Although detection thresholds will be fine-tuned as diagnostic use develops, Prof Wong believes the trial has important lessons for clinicians.
He said: “This study confirms that the existing ‘gold standard’ of pre-biopsy detection – the MRI – is indeed a high benchmark. Even with fine-tuning, we suspect PSMA PET/CT won’t replace the MRI as the main method of prostate cancer detection. But it will likely have application in the future as an adjunct to the MRI, or for people for whom an MRI is unsuitable, or as a single combined “diagnostic and staging” scan for appropriately selected patients.”
Source: EurekAlert!
