Originally published 6/27/2017
There is a difference between insignificant and significant prostate cancer (PCa). While opinion remains mixed regarding the need to treat insignificant PCa immediately—or whether some cases might never need treatment—agreement is virtually universal that significant PCa is not trustworthy and should thus be dealt with as soon as possible. Therefore, detecting this potentially lethal disease as early as possible offers the best cancer-free survival odds.
The only sure way to diagnose PCa is a needle biopsy. The majority of the million biopsies performed annually in the U.S. are systematic, yet random, needle sticks guided by transrectal ultrasound (TRUS). This is problematic, with an error margin such that finding insignificant disease does not rule significant disease that was missed. Here’s where multiparametric MRI (mpMRI) imaging excels, because it spotlights and defines significant disease before a biopsy, and if no significant disease is detected, a biopsy can be avoided.[i]
An October 2021 journal article gives a great example of mpMRI finding significant disease in patients whose biopsies indicated insignificant disease. In the study conducted by Emekli et al., 80 biopsy-positive 3+3=6 patients underwent mpMRI and were then treated by radical prostatectomy (RP).[ii] When their mpMRI PI-RADS scores were compared with their post-RP prostate specimens, it showed that mpMRI had correctly distinguished the insignificant from the significant tumors with 96.3% accuracy. In fact, out of the 80 patients diagnosed as clinically insignificant, two-thirds had PI-RADS 4-5, or significant disease. The authors concluded: “mpMRI is a reliable and non-invasive diagnostic method that can complement biopsy results in decision-making in patients who are initially evaluated as low risk.” This study boosts our confidence in MRI’s detection power for clinically significant disease. Perhaps we should change the original blog title to “MRI for Clinically Significant Prostate Cancer? If You See It, It’s There.”
Multiparametric MRI of the prostate is once again in the news – the urological news, that is. A research group at Yale University School of Medicine[iii] wondered, “If a man has a multiparametric MRI (mpMRI) of the prostate and it doesn’t show significant prostate cancer (PCa), what are the chances that it’s wrong?” This is an excellent question, given that studies have shown that mpMRI done by experts has roughly 98% accuracy in detecting significant cancer. And whether or not the PCa is significant has a huge bearing on whether the patient needs treatment, and how soon. In fact, a growing number of clinicians are recommending Active Surveillance, not immediate treatment, for patients with low-risk (insignificant) disease.
For the Yale study, the team identified 670 cases of men who had mpMRI between 2012-16. Out of that cohort, 100 men had no suspicion of significant prostate cancer (Gleason grade 3+4 or higher) based on their MRI results. To confirm this, the researchers conducted a 12-core template biopsy on every patient. They found 27% of the men had insignificant prostate cancer, that is, small low-risk tumors that mpMRI would be expected to not pick up. 3 of the men (3%) had Gleason 7 or higher detected by biopsy.
Based on this, the researchers wrote, ““Our results suggest that avoidance of systematic biopsy in patients with negative imaging results may be feasible.”[iv] This is good news for patients. It basically says that it’s well worth it to have a prostate mpMRI before undergoing a biopsy, because only when the scan shows an area suspicious for Gleason 7 or higher PCa should a biopsy be the next step. If the mpMRI does indicate the need for a biopsy, the best approach is to have it done inside the MRI in order to guide a minimum number of needles into the precise target for the most accurate diagnosis.
The study authors offer the most logical advice: “There is an approximately 3% chance of detecting clinically significant prostate cancer with systematic TRUS-guided biopsy in patients with no suspicious findings on mpMRI. This information should help guide recommendations to patients about undergoing systematic TRUS-guided biopsy when mpMRI is negative.”[v] It’s always nice when the news is good.
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.
[i] Ryoo H, Kang MY, Sung HH, Chang Jeong B, Seo SI, Jeon SS, Lee HM, Jeon HG. Detection of prostate cancer using prostate imaging reporting and data system score and prostate-specific antigen density in biopsy-naive and prior biopsy-negative patients. Prostate Int. 2020 Sep;8(3):125-129
[ii] Emekli E, Gündo?du E, Özen A. Evaluation of multiparametric prostate magnetic resonance imaging findings in patients with a Gleason score of 6 in transrectal ultrasonography-guided biopsy. Pol J Radiol. 2021 Oct 29;86:e608-e613.
[iii] Lu AJ, Syed JS, Nguyen KA, Nawaf CB et al. Negative Multi-Parametric MRI of the Prostate Predicts Absence of Clinically Significant Prostate Cancer on 12-Core Template Prostate Biopsy. Urology. 2017 Mar 16. pii: S0090-4295(17)30247-9. doi: 10.1016/j.urology.2017.01.048. [Epub ahead of print]
[iv] Chernow, Jody. “Prostate Biopsy May be Avoidable if MRI Findings are Negative.” Mar. 23, 2017. http://www.renalandurologynews.com/prostate-cancer/multiparametric-mri-negative-findings-prostate-cancer-unlikely/article/646000/
[v] Lu et al., ibid.