In the not-so-distant past, a PSA blood test that showed an elevated or rising PSA most often led to a transrectal ultrasound (TRUS) guided needle biopsy of the prostate. Most TRUS biopsies involve 12 or more needles for the simple reason that ultrasound cannot clearly identify what’s a tumor and what isn’t. And unfortunately, this “hunt-and-peck” blind biopsy method has too often been inadequate and/or inaccurate because 12 needles only samples roughly 1% of the gland.

This means that:

• many men were needlessly biopsied or over-biopsied, putting them at risk for pain and infection
• many men with low-risk prostate cancer (PCa) were sent for whole gland treatments that left them with short-term, long-term, or late-onset side effects (urinary, sexual, bowel)
• many men who were told they could do watchful waiting (WW) or active surveillance (AS) had underdiagnosed aggressive PCa that advanced to a later stage before discovery

Using mpMRI to correct past flaws

Multiparametric MRI (mpMRI) has demonstrated that it can fulfill 5 roles in which PSA screening and TRUS biopsies have fallen short.

1. Screening for PCa – A paper published in the Feb. 2021 issue of JAMA compared PCa screening using PSA, ultrasound, and a short MRI protocol. MRI vs. PSA alone (3 ng/mL or higher) diagnosed more men “with clinically significant cancer, without an increase in the number of men advised to undergo biopsy or overdiagnosed with clinically insignificant cancer.” There was “no evidence” that ultrasound would have performed better than PSA alone.^[i]
2. First response to suspicious PSA – The PSA blood test is not without merit as biomarker, except it is not specific for cancer. Men whose PSA is suspicious for PCa (including after a repeat PSA) should not automatically be referred for a biopsy. Instead, studies have shown that mpMRI before biopsy can prevent up to 40% of unnecessary biopsies.^[ii]
3. High PSA with previous negative biopsy – Another problem with TRUS biopsies is that if the first biopsy missed PCa, repeat biopsies are also unlikely to hit the tumor since the same systematic pattern is followed. If an initial biopsy missed PCa at, say, the anterior of the gland, there’s a good likelihood that a 2nd and even 3rd biopsy will miss it even as it continues to multiply. Therefore, an MRI before a repeat biopsy is “the most validated and accepted indication” for prostate MRI.^[iii]
4. Targeting biopsy needles – This is a huge advance in PCa diagnosis! Since mpMRI can depict the size, shape and location of abnormal lesions in the prostate gland, under the guidance of real time, in-bore (in the magnet tunnel) imaging, only a small number of needles are needed to sample precise locations within the lesion. The advantage is not only minimal infection risk, but also the ability to capture the most dangerous “founding cells” that pose the greatest danger. This means accurate knowledge of the cancer in order to determine the best treatment match. IMPORTANT NOTE – Fusion guidance that merges real-time TRUS with previously captured MRI slices is definitely not real time MRI targeting! Don’t be misled by those who may tell you that fusion-guided targeted biopsies are MRI-targeted. This is not the case. In fact, doctors who use fusion targeting often add a 12-core systemic biopsy during the same biopsy session, on the chance that the fusion guidance missed the mark.
5. Monitoring active surveillance (AS) – A greater percentage of low-risk PCa patients than ever before choose to go on AS in order to defer treatment. According to a study published in JAMA, “The use of active surveillance increased from 14.5 percent to 42.1 percent of men with low-risk prostate cancer between 2010 and 2015…”^[iv] There are three main reasons for this growing trend: a) avoid the side effects of whole-gland treatment as long as safely possible; b) better diagnostics more accurately identify which men are truly low-risk; and c) mpMRI monitoring for any tumor growth or progression that would trigger a treatment window.

Of course, there are other ways in which mpMRI is advantageous during the clinical pathway of PCa, but these are the current top five uses. It is worth noting that noninvasive mpMRI has the highest detection rate of clinically significant PCa, which makes it possible to identify those situations in which a biopsy is clearly warranted. Thanks to real time MRI targeting, the most accurate diagnosis using a minimum of needles offers doctors and patients a high degree of confidence in determining the treatment approach that best serves the clinical and lifestyle needs of each individual.

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] Eldred-Evans D, Burak P, Connor MJ, Day E et al. Population-Based Prostate Cancer Screening With Magnetic Resonance Imaging or Ultrasonography: The IP1-PROSTAGRAM Study. JAMA Oncol. 2021 Mar 1;7(3):395-402.
[ii] Klotz L, Chin J, Black PC, et al. Comparison of Multiparametric Magnetic Resonance Imaging–Targeted Biopsy With Systematic Transrectal Ultrasonography Biopsy for Biopsy-Naive Men at Risk for Prostate Cancer: A Phase 3 Randomized Clinical Trial. JAMA Oncol. Published online February 04, 2021.
[iii] Tempany C, et al. The Role of Magnetic Resonance Imaging in Prostate Cancer.” Mar. 26, 2021. https://www.uptodate.com/contents/the-role-of-magnetic-resonance-imaging-in-prostate-cancer#H14499361
[iv] Mahal BA, Butler S, Franco I et al. Use of Active Surveillance or Watchful Waiting for Low-Risk Prostate Cancer and Management Trends Across Risk Groups in the United States, 2010-2015. JAMA. 2019;321(7):704-706.