Originally published 2/15/2022
To bolster the findings of Australian research described in the blog below, we present an even more rigorous study out of UCLA that points to superior detection of localized PCa by multiparametric MRI (mpMRI) vs. PSMA PET.
While PSMA PET is now the imaging standard for metastatic PCa, the purpose of the UCLA research was to clarify which imaging modality best defines intermediate-to-high risk disease before metastasis.
The study involved 134 patients who had mpMRI and PSMA PET prior to prostatectomy; imaging results were compared with the post-surgical gland specimens, and each imaging method “… was interpreted by 3 independent readers who were unaware of the other modality result.”[i]
The authors found that mpMRI and PSMA PET had “similar accuracy” in detecting PCa within the gland. However, mpMRI “performs better” at identifying tumor activity extending beyond the capsule as well as seminal vesicle invasion.
They concluded, “For the T-staging evaluation of intermediate to high risk prostate cancer, mpMRI should still be considered the imaging modality of reference.” They also suggest that if PSMA PET is available, adding it to mpMRI could improve accurate estimation of tumor extent.
One of the most exciting gatherings of medical minds is the Annual Congress of the European Association of Urology (EAU). Urology Today describes it as “Europe’s biggest urological event with specialists and affiliated medical professionals gathering for a critical assessment of clinical practices and key research developments.” I think of such events as a kaleidoscope, a vision of exhilarating colorful shapes that change with the slightest movement yet always form an orderly pattern.
The world of urologic imaging is constantly in motion as technologies and discoveries evolve. Most recently, Prostate Membrane Specific Antigen (PSMA) PET scans have been found to be very accurate in detecting tiny sites of metastatic prostate cancer (PCa). This is a gamechanger for patients with suspected PCa spread, since the earlier it is identified, the greater chance of successful treatment planning to control their disease.
Is PSMA PET useful for localized PCa before biopsy?
The application of PSMA PET scans to identify mets naturally led to exploring its merits for men whose abnormal PSA raises suspicion of PCa. In the traditional diagnostic pathway, such men would be referred for a transrectal ultrasound (TRUS) guided biopsy using a minimum of 12 needles. This conventional protocol is giving way to the use of multiparametric MRI (mpMRI) before biopsy. Studies show that this method helps avoid a needle biopsy if mpMRI does not indicate the presence of significant PCa. On the other hand, if significant PCa is found by this noninvasive imaging, an in-bore MRI-guided targeted biopsy offers the most accurate diagnosis with the fewest needles. It’s no wonder that as the kaleidoscope of medical innovation has shifted, MRI is now an undeniable stand-out in PCa detection.
It was inevitable, therefore, that someone would test PSMA PET before biopsy to find out how it stacks up against mpMRI. To compare the two methods, a research team from Australia designed a multicenter study involving 240 men suspected of PCa, and they presented their findings at the July 1-4, 2022 EAU Annual Congress (Amsterdam, The Netherlands).
All patients underwent both PSMA PET and mpMRI scans of the prostate/pelvic bed. Out of the total group, 181 were found to have abnormalities that justified a needle biopsy. According to a news report, “…the researchers found that MRI had a 75 percent accuracy rate for detecting prostate cancer in comparison to a 62 percent accuracy rate for PSMA PET/CT.”[ii]
Lead author Dr. Lih-Ming Wong observed, “Our analysis found that MRI scans were better than PSMA PET for detecting any grade of prostate cancer… 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 MRI as the main method of prostate cancer detection.”[iii] That said, Dr. Wong believes PSMA PET may have value as an adjunct in combination with MRI for certain patients with localized PCa.
Based on our own experience at the Sperling Prostate Center, we view prostate mpMRI as The King of Prostate Imaging. Needless to say, we were glad to see the news of Dr. Wong’s presentation to the EAU. The kaleidoscope will always bring changes, but MRI will remain a bright gem in the array of patterned colors.
NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.
References
[i] Sonni I, Felker ER, Lenis AT, Sisk AE et al. Head-to-Head Comparison of 68Ga-PSMA-11 PET/CT and mpMRI with a Histopathology Gold Standard in the Detection, Intraprostatic Localization, and Determination of Local Extension of Primary Prostate Cancer: Results from a Prospective Single-Center Imaging Trial. J Nucl Med. 2022 Jun;63(6):847-854.
[ii] Hall, Jeff. Study Confirms Higher Accuracy of MRI Over Emerging PSMA PET/CT for Diagnosing Prostate Cancer. Diagnostic Imaging, July 8, 2022. https://www.diagnosticimaging.com/view/study-higher-accuracy-of-mri-over-psma-pet-ct-for-diagnosing-prostate-cancer
[iii] Ibid.
About Dr. Dan Sperling
Dan Sperling, MD, DABR, is a board certified radiologist who is globally recognized as a leader in multiparametric MRI for the detection and diagnosis of a range of disease conditions. As Medical Director of the Sperling Prostate Center, Sperling Medical Group and Sperling Neurosurgery Associates, he and his team are on the leading edge of significant change in medical practice. He is the co-author of the new patient book Redefining Prostate Cancer, and is a contributing author on over 25 published studies. For more information, contact the Sperling Prostate Center.
