Should MRI to detect prostate cancer be the standard of care? Results From the First Randomized Trial are in!
Prostate cancer care has seen tremendous advances over the last ten years. As urologists, we have become more thoughtful about the over treatment of low grade cancers and new technologies such as MRI have given us tools to better risk stratify patients and offer surveillance to more patients. A fascinating new multi-institutional study from Europe, the PRECISION trial, found that MRI prior to biopsy of the prostate for cancer detection is superior to standard ultrasound-guided biopsy among men at risk for prostate cancer, published in the New England Journal of Medicine.
The design of the study was excellent: a randomized, non-inferiority trial to examine the benefit of MRI with or without targeted biopsy as an alternative to standard US-guided biopsy for prostate cancer detection in five hundred men suspected of having cancer. If the MRI was suggestive of prostate cancer, men in the MRI-targeted biopsy group underwent a targeted biopsy(either fusion or cognitive biopsy). The men whose MRI results were not suggestive of prostate cancer were not offered a biopsy. Standard biopsy was a 12–core transrectal biopsy. The goal of the study was to determine the proportion of men who received a diagnosis of clinically significant cancer (gleason 7 or higher) versus clinically insignificant cancer (gleason 6).
“Why is the study important? PRECISION is the first randomized trial to show that using MRI at the start of the prostate cancer diagnosis process is beneficial. ”
Clinically significant cancer was detected in 38% of men in the MRI-targeted biopsy group, as compared with 26% in the standard-biopsy group. 28% of men in the MRI group had a "negative" MRI (not suggestive of prostate cancer) so they did not undergo biopsy. I find the cancer detection even more impressive given that over a quarter of men in the MRI group did not even have a biopsy yet were included in the final calculations as "no-cancer". Even better, fewer men in the MRI group than in the standard group received a diagnosis of clinically insignificant cancer. Why is this important? we know from our own research published in European Urology that gleason 6 prostate cancer is generally confined to the prostate and rarely spreads outside the prostate or to other parts of the body.
Why is the study important? PRECISION is the first randomized trial to show that using MRI at the start of the prostate cancer diagnosis process is beneficial. Currently, the American Urological Association recommends using MRI after your first negative biopsy if there is still concern for cancer. PRECISION showed what many urologists such as myself using MRI regularly suspected: MRI combined with a targeted biopsy technique leads to more cancers being diagnosed than the standard way we have been performing prostate biopsies for the last 25 years.
Ultimately, a common question I get from patients with a negative MRI is if they can then avoid doing a biopsy? Unfortunately, several studies have confirmed that even in men who have a completely negative MRI, we know somewhere between 10 and 20 percent of men will have a clinically significant cancer. I do believe we will eventually be able to combine MRI information with blood biomarkers to avoid biopsy in many of the over one million men who currently undergo a biopsy in the US annual. We hope to provide patients in the bay area the best options for to risk stratify their cancers and limit overtreatment whenever possible.