Originally published 9/5/2019
The original blog below summarized a 2019 paper (Kasivisvanathan et al.) on the striking advantage of MRI-targeted biopsy over conventional systematic TRUS biopsy.
The use of fewer needles under MRI guidance diagnoses more significant tumors while avoiding overdiagnosing insignificant tumors. This reduces the number of overtreated cases and their side effect risks.
This update cites an April 4, 2023 article by Richard Hoffman (U. of Iowa Carver College of Medicine), who comments on the comparison study by Hugosson, et al.
The 2022 Hugosson study included over 17,000 patients who received either MRI-targeted biopsy or conventional systematic biopsy.
Hoffman noted that, “The MRI-targeted biopsy alone identified fewer low-risk prostate cancers compared with the systemic biopsy protocol and reduced the number of unnecessary biopsies performed. It also showed a similar rate of detection of clinically significant prostate cancer as the systemic approach…”[i]
We anticipate that future studies will continue to confirm the benefits of MRI-targeted biopsy over traditional blind, randomized TRUS-guided biopsies.
There’s a quip that goes, “If fifty people tell you you’re drunk, fall over.” The point is obvious. When you know you’re outnumbered, back down.
Since the early 1990s, prostate needle biopsy using transrectal ultrasound (TRUS) guidance has been the reigning method for diagnosing prostate cancer (PCa). Compared to prior biopsy methods, it was a relative walk in the park. (For a rather bloodcurdling history of 20th century open biopsy methods before imaging guidance, read The Development of the Modern Prostate Biopsy.) Transrectal ultrasound not only made prostate biopsy less invasive, it also had economic advantages. The equipment is affordable for urology practices, and the procedure can be done in an office setting.
In its early days, TRUS biopsy involved taking three samples from each side of the prostate—total of six sites—so it was called a sextant biopsy. As time passed, it became clear from comparing biopsy reports with actual post-prostatectomy specimens that six needles did not sample enough of the gland, thereby missing or underdiagnosing PCa. Gradually 10-12 needles became standard, with many urologists preferring 12-14 needles. As a consequence, side effect risks—including infection—rose.
Introducing Magnetic Resonance Imaging (MRI)
The problem with TRUS guidance is its inability to identify suspicious areas within the gland. Ultrasound lacks the imaging power to define tissue differences, so needles were aimed according to a conceptual “grid” of the prostate, in hopes of a positive “hit.” In reality, as we now know, much insignificant PCa was picked up while significant PCa was missed. Since PCa can only be definitively diagnosed from tissue samples, a more precise way to identify needle placement for maximum diagnostic power was needed.
With the introduction of multiparametric MRI that can visually characterize tissue differences, doctors now had a tool for identifying suspicious areas to sample, and for guiding individual needles directly into those areas. However, as often happens, implementing this new approach met with objections:
“Too expensive!”
“Have to get the patient to a radiology suite.”
“Urologists aren’t trained to interpret MRI scans.”
An “attractive alternative” to TRUS biopsy
Despite the resistance, evidence has been accumulating in favor of real-time MRI guidance for targeted prostate biopsies. An impressive May, 2019 journal article by Kasivisvanathan et al. compares MRI-targeted biopsy (MRI-TB) vs. systematic TRUS biopsy for detecting and diagnosing PCa.[ii] I say impressive because the authors represent several authoritative academic, research and clinical urology centers in Europe. All centers/departments are urologic, so we can rule out a bias toward radiology.
The purpose of their work was “to compare the detection rates of clinically significant and clinically insignificant cancer by MRI-TB with those by systematic biopsy in men undergoing prostate biopsy to identify prostate cancer.” For their analysis, the authors compiled and analyzed results from 76 previously published clinical studies involving a total of 14,709 men! They included 68 prospective or retrospective studies with a paired design (MRI-TB compared with systematic TRUS biopsy) and 8 randomized controlled trials (men assigned randomly to either MRI-TB or TRUS).
They found that MRI-TB accurately detected more men with clinically significant PCa and fewer men with insignificant PCa than TRUS biopsy. Also, the proportion of needle cores that were positive for PCa was greater for targeted than systematic biopsy, demonstrating that directing biopsy needles into the heart of a suspicious area is more productive in gaining a true idea of tumor volume. They conclude that “MRI-TB is an attractive alternative diagnostic strategy to systematic biopsy.”
The patient’s (and urologist’s) best interest
What is the best thing a urologist can do for the patient as well as for him/herself? Obviously, it’s to make sure the patient receives the best PCa treatment. That means achieving the most strategic balance between cancer control and lifestyle issues. Matching the treatment to the disease is only possible when the most detailed portrait of the tumor has been obtained—which is achievable today only by integrating multiparametric MRI into the diagnostic pathway. Whether the treatment choice is surgery, radiation, ablation or Active Surveillance, if the patient is well-served, the doctor is too. Everyone wins when the diagnosis and treatment are done according to the patient’s best interest.
The Kasivisvanathan analysis, developed out of nearly 15,000 cases, is a solid step toward amassing the kind of numbers needed to persuade urologists that MRI is a patient’s best friend when it comes to detection and diagnosis. Hopefully, when TRUS finally recognizes it’s outnumbered, it will ultimately back down.
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] Kasivisvanathan V, Stabile A, Neves JB, Giganti F et al. Magnetic Resonance Imaging-targeted Biopsy Versus Systematic Biopsy in the Detection of Prostate Cancer: A Systematic Review and Meta-analysis. Eur Urol. 2019 May 23.
[ii] Kasivisvanathan V, Stabile A, Neves JB, Giganti F et al. Magnetic Resonance Imaging-targeted Biopsy Versus Systematic Biopsy in the Detection of Prostate Cancer: A Systematic Review and Meta-analysis. Eur Urol. 2019 May 23.
About Dr. Dan Sperling
Dan Sperling, MD, DABR, is a board certified radiologist who is globally recognized as a leader in multiparametric MRI for the detection and diagnosis of a range of disease conditions. As Medical Director of the Sperling Prostate Center, Sperling Medical Group and Sperling Neurosurgery Associates, he and his team are on the leading edge of significant change in medical practice. He is the co-author of the new patient book Redefining Prostate Cancer, and is a contributing author on over 25 published studies. For more information, contact the Sperling Prostate Center.
