This question introduces A new European study involving nearly 600 participants over a three-year period raises an important question: “Is it safe to omit biopsy following negative magnetic resonance imaging (MRI) results in men with clinically suspected prostate cancer?”^[i] Indeed, safety should always be the top priority in any clinical intervention, no matter how minor and seemingly harm-free. If doctors wore badges, they might bear the motto, “To help, or at least to do no harm.”

But sometimes there are trade-offs between helping and harming. This is often the case with prostate biopsy: it’s a balancing act between safety and damage control. The end goal of the biopsy is to diagnose prostate cancer (PCa); after all, protecting men from a potentially life-threatening disease is the safest course of action. On the other hand, standard TRUS-guided systematic biopsies risk causing harm:

• Discomfort/pain
• Blood in urine or semen
• Erectile dysfunction
• Infection
• Diagnostic inaccuracy (over-detecting insignificant PCa, under-detecting significant PCa).

This created a problem. Until multiparametric MRI (mpMRI) was introduced as an intermediate step between a blood test and a biopsy, men whose PSA was suspiciously high were routinely sent for a TRUS-guided biopsy. In turn, this led to thousands of men being overdiagnosed and overtreated, which may have eradicated their cancer but left them with incontinence, impotence or bowel problems.

Thankfully, following a high PSA result with mpMRI enables identifying probable aggressive areas that should be biopsied. No one disagrees with that. However, what if mpMRI does NOT reveal such areas? Is it safe to assume there’s no need to biopsy the patient, despite a suspiciously high PSA? That’s exactly what the 3-year study mentioned at the beginning was designed to test.

A total of 593 men who were suspected of having PCa (based on PSA and/or digital rectal exam) were enrolled across 54 urology centers. None had yet had a biopsy at the time of enrollment. Once enrolled, all had mpMRI scans, but only those with positive imaging results had immediate biopsy, and all were monitored for three years. The study recorded and reported:

1. The proportion of prostate biopsies avoided by first using mpMRI
2. The proportion of men with insignificant PCa (Grade Group 1)
3. The proportion of men with significant PCa (Grade Group ≥2) eventually detected in men with initial negative MRI results (low risk) and initial positive MRI results (intermediate/high risk).

At the outset 307 men (52%) had positive MRI results, while 286 (48%) had negative results. Of the men with positive MRIs, 270 underwent immediate biopsy (the 37 who did not were excluded from further analysis due to violation of study protocol); 58 biopsied men were found to have insignificant PCa while 161 had significant PCa. Eventually, 44 of the 286 men with negative MRI a had biopsy at some point during monitoring but the remaining 242 had no biopsy during the entire study.

In terms of the men whose initial MRI was negative, 233 entered and completed 3-year monitoring. This group is of particular interest when we ask if it’s safe to avoid biopsy after a negative MRI. Monitoring consisted of clinical exams, PSA tests, digital rectal exams, and follow-up MRI as needed, with biopsy triggered as needed. Over the cumulative three-year period, an average of 15% needed a follow-up MRI, 14.2% had a biopsy, and 4% were diagnosed with PCa at three years.

After computing all statistics, the authors declared that “prebiopsy prostate MRI, as an integral component of the MRI pathway, is feasible in a community-based setting and oncologically safe.”^[ii] Over 3 years of monitoring, only 4% of their study participants with a negative MRI developed clinically significant PCa. Thus, for their population, a negative MRI had a 96% probability of accurately predicting there is no cancer. According to their numbers, adding prebiopsy MRI prevented prostate biopsy in 41% of their total enrollees, and 86% of men with initial negative MRI results over three years. Stated another way, skipping a biopsy based on negative MRI results has a very low probability of putting a patient’s life in danger provided he participates in monitoring. “Thus, prebiopsy MRI may not only improve cancer detection at biopsy, but also identify men who can safely omit biopsy.”^[iii]

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] Hamm CA, Asbach P, Pöhlmann A, Schoots IG et al. Oncological Safety of MRI-Informed Biopsy Decision-Making in Men With Suspected Prostate Cancer. JAMA Oncol. 2024 Dec 12.
[ii] Ibid.
[iii] Ibid.