ASCO interview about the latest care for men with prostate cancer. PCRI’s Dr. Foster interviews Dr. Tanya Dorff about Active Surveillance and MRI.
Two Important Reports about the Accuracy of MRI Imaging
Every year in the United States one million men undergo prostate biopsy. A biopsy has a number of potential complications including serious infections requiring hospitalization.
Despite these risks, the greater danger from biopsy is the over-diagnosis of Low-Risk cancer. Over-diagnosis is the underlying reason that the US Preventative Services Task Force has recommended that PSA screening be stopped. In the United States, eighty-five percent of men who are diagnosed with Low-Risk prostate cancer will undergo radical treatment even though studies show that they can be safely watched on active surveillance.
Yet how can we consider abandoning PSA screening when studies show that it reduces the risk of dying from prostate cancer? How can this conundrum be resolved? Is there a way to spare the men with Low-Risk disease from being overtreated while still detecting High-Risk prostate cancer before it spreads?
Historically, random biopsy has been the only accurate method for detecting prostate cancer. However, for every case of High-Risk cancer found with random biopsy, four or five men are diagnosed with Low-Risk disease usually leading to unnecessary treatment.
Two reports from the 2013 American Urology Association meeting indicate that modern multi-parametric MRI detects High-Risk prostate cancer very accurately.
In Abstract #2051 Dr. Noboru reported his findings in 320 men with PSA levels less than 10. They compared MRI with a standard 14-core biopsy. Only one man with very low volume disease in the Gleason 8-10 category was missed by MRI.
In Abstract # 1444 Dr. Emberton found that MRI accurately predicted the absence of any High-Grade cancer (Gleason score of 3 + 4 = 7 or above) with 95% accuracy. Both Dr. Emberton and Dr. Noboru used a standard 1.5 Tesla MRI. Three Tesla MRI, available select centers, is even more accurate.
High-quality prostate imaging is a potential solution to the PSA screening conundrum. Imaging detects High-Risk cancer that needs treatment. Men with Low-Risk disease can use the imaging to accurately monitor themselves on active surveillance.
PSA screening is not the culprit for so many men being overtreated for prostate cancer. It is the prevailing policy of performing an immediate random, multi-core biopsy on every man with a PSA above 4.0. Fortunately, modern MRI imaging has finally become accurate enough to offer a viable alternative to the traditional biopsy approach.