New imaging technology less accurate than MRI at detecting prostate cancer

A team of researchers in Australia and New Zealand has found that MRI scans can detect prostate cancer more accurately than the newer, prostate-specific -PSMA PET/CT scanning technique. The findings are being presented today at the European Association of Urology's annual congress (EAU22), in Amsterdam.

Prostate-specific membrane antigen (PSMA) PET/CT scans, approved by the US FDA in 2020, use a radioactive dye to 'light up' areas of PSMA, which is found on the surface of prostate cancer cells. They are presently used to manage prostate cancer, as they can accurately measure the progression or recurrence of the disease. So, in this trial the researchers set out to find if they could be used to diagnose prostate cancer as well.

The PEDAL trial recruited 240 patients across five hospital groups who were at risk of prostate cancer. Every patient was 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.

Since each patient had both type of scans, the researchers could assess which type had more accurately detected those patients who had prostate cancer. The researchers found that MRI scans were significantly more accurate at detecting any grade of prostate cancer than the PSMA PET scans (0.75% for MRI vs 0.62% for PSMA PET).

The 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 concluded the researchers.

Reference: "New imaging technology less accurate than MRI at detecting prostate cancer, trial shows" EUROPEAN ASSOCIATION OF UROLOGY.