A team of researchers from Australia and New Zealand have found that MRI scans can detect prostate cancer more accurately than the newer prostate-specific PET / CT -PSMA scan technique.
The findings are presented today at the annual congress of the European Association of Urology (UAE22), in Amsterdam.
PET / CT scans of prostate-specific membrane antigen (PSMA), approved by the U.S. FDA in 2020, use a radioactive dye to “illuminate” areas of PSMA, which is found on the surface of the skin. prostate cancer cells. They are currently used to control prostate cancer because they can accurately measure the progression or recurrence of the disease. Thus, in this trial, the researchers set out to find out if they could also be used to diagnose prostate cancer.
The PEDAL trial recruited 240 patients from five hospital groups at risk for prostate cancer. All patients underwent an MRI and a PSMA PET / CT scan. If the images suggested the presence of prostate cancer, the patient’s urologist did a biopsy.
MRI scans detected abnormalities in 141 patients, while PET / CT PSMA scans detected abnormalities in 198 patients. A total of 181 patients (75%) underwent a prostate biopsy, and subsequently 82 of these patients were found to have clinically significant prostate cancer.
Because each patient had both types of scans, the researchers were able to assess which type had more accurately detected those patients who had prostate cancer. The researchers found that MRI scans were significantly more accurate in detecting any degree of prostate cancer than PSMA PET scans (0.75% for MRI vs. 0.62% for PSMA PET).
Associate Professor Lih-Ming Wong, a uro-oncology consultant at St Vincent’s Hospital in Melbourne, Australia, led the research team. He said: “Our analysis found that MRI scans were better than PSMA-PET for detecting any degree of prostate cancer. When we looked at only clinically significant prostate cancers, there was no difference in accuracy. Because this study is one of the first to explore the use of PSMA-PET to diagnose prostate cancer, we are still learning and adjusting how to improve the use of PSMA-PET in this environment.
Although screening thresholds will be adjusted as diagnostic use develops, Professor Wong believes the trial has important lessons for physicians.
He says: “This study confirms that the existing ‘gold standard’ of pre-biopsy detection, magnetic resonance imaging, is really a high benchmark. Even with the fit, we suspect that PSMA PET / CT will not replace the MRI as the primary method of detecting prostate cancer. But it will probably be used in the future as a supplement to MRI, or for people for whom MRI is not appropriate, or as a combined scan of ” diagnosis and staging “for appropriately selected patients”.
He continues: “That’s why these solid studies are crucial so that we can better understand the role these technologies can play at every stage of the cancer journey and advance prostate cancer management.”
Professor Peter Albers, President of the Scientific Office of the European Association of Urology, comments: “New diagnostic tools must be tested as carefully as new drugs, so we welcome the results of ‘this remarkable phase III trial, which showed that MRI was superior in the detection of any prostate cancer.
“It also showed that PSMA PET / CT was not inferior to MRI in the detection of clinically significant cancers (ISUP 2 and above); and that the ultimate goal of primary staging will be to detect only the most aggressive cancers and avoid unnecessary biopsies, this is not the end of the story More research will be needed to explore the PSMA PET / CT correlation between standard absorption value (SUV) and cancer aggressiveness, but first steps have been taken to find the best diagnostic approach for clinically significant prostate cancer “.
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