When it comes to treating prostate cancer (PCa), proof matters. There’s a legend about a Missouri Congressman at the turn of the 20th century, Willard D. Vandiver. As a member of the House Committee on Naval Affairs, he gave a speech at a naval banquet in which he stated, “I come from a state that raises corn and cotton and cockleburs and Democrats, and frothy eloquence neither convinces nor satisfies me. I am from Missouri. You have got to show me.” In other words, evidence carries persuasive power.
Magnetic resonance imaging is revolutionizing prostate cancer (PCa) treatment by making minimally invasive focal treatment possible for qualified patients. For those who want proof, a Finnish multidisciplinary team reviews published data on TRUS-guided focal therapy. They then present two new next-generation MRI-guided focal therapies: TULSA-PRO and MRI-guided Focused Ultrasound.[i]
Evolving prostate cancer treatment
The authors begin by noting the improved accuracy of PCa detection and diagnosis thanks to multiparametric MRI (mpMRI), the “King of Prostate Imaging”. Since MRI can identify the roughly 30% of patients who have a single focus of disease, clinicians reasoned that focal PCa ablation for such patients offers a safe and feasible alternative to whole-gland (radical) treatments which often result in urinary or sexual harm. Minimal-to-noninvasive procedures are now rapidly evolving. Without creating a surgical wound or applying radiation, these procedures deliver targeted tumor destruction. However, transrectal ultrasound (TRUS) can’t define cancerous tissue, whereas MRI can. The authors write, “Promisingly, combining MRI with newer generation ablation methods has improved the treatment’s accuracy.” In fact, mpMRI is now well established to plan, guide, monitor and confirm focal therapy.
To underscore the merits of focal treatment in general, the authors cite numerous papers on TRUS guided focal HIFU (high intensity focused ultrasound) to illustrate the following points:
- Compared with whole-gland ablation, two studies show that TRUS-guided focal therapy has similar cancer control rates at six and eight years.
- Compared with rates of urinary continence after radical prostatectomy, TRUS-guided focal ablation rates are significantly higher (in some studies as high as 100% continence).
- Compared with reported rates of full erectile function at 1 year after prostatectomy (28%), TRUS-guided focal ablation rates at 1 year are significantly higher (52-100%).
Two new MRI-guided methods: TULSA and MRgFUS
Having presented evidence for the efficacy and low side effects of TRUS-guided focal therapy, the authors describe two new FDA-approved MRI-guided therapies that utilize ultrasound energy to kill PCa.
The first, Transurethral ultrasound ablation (TULSA) is applied by a small instrument placed through the penis into the prostatic urethra. As the authors describe it, TULSA differs from the more common transrectal HIFU which relies on “sonications” or rapid small volume targeted beams of sound waves. Instead, “TULSA technology has distinct patterns of thermal dose and temperature deposition and subsequent tissue damage due to the use of continuous heating with an unfocused ultrasound beam.”[ii]
The second new method, MRI-guided Focused Ultrasound (MRgFUS) is similar to conventional transrectal HIFU based on sonications. The difference lies in MRI guidance vs. transrectal ultrasound guidance. MRI is simply more accurate because it depicts the tumor itself in real time (which ultrasound cannot do), and has thermometric software to monitor and track tissue temperatures.
Both TULSA and MRgFUS are performed in the bore (tunnel) of the magnet, with real-time MRI monitoring and temperature feedback control. Also, the success of the treatment can be immediately evaluated after the procedure by means of contrast-enhanced MRI scanning.
By basing their premise regarding the cancer control and low side effect profile of focal therapy in factual longer term study results, the authors establish a foundation for confidence that MRI-guided ablation will prove at least as safe, effective and accurate, if not even better, than TRUS guided ablation. The Sperling Prostate Center shares that confidence, leading the way in providing a full suite of three MRI-guided focal therapies: Focal Laser Ablation (FLA), TULSA, and Exablate MRgFUS. For more information on how the power of MRI diagnosis, planning, monitoring and confirming success can fulfill its promise for you, contact us.
Are you a candidate for MRI-guided focal therapy?
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] Anttinen M, Blanco Sequeiros R, Boström PJ, Taimen P. Evolving imaging methods of prostate cancer and the emergence of magnetic resonance imaging guided ablation techniques. Front Oncol. 2022 Nov 17;12:1043688.