Just as Ponce de Leon sought in vain for a fountain of youth, it appears that the search for a whole gland prostate treatment that will reliably preserve sexual function remains fruitless for the time being. At least, based on medium-term outcomes of whole gland HIFU announced by Dr. Mark Emberton’s team, it sure looks that way.
HIFU (high intensity focused ultrasound) is a noninvasive prostate cancer treatment for localized disease that uses sound waves to destroy the cancer. U.S. patients waited hopefully for FDA approval for well over five years, while HIFU was being routinely offered in Europe, Japan, Mexico, China and many South American countries. Since there’s no surgery or radiation, this outpatient ultrasound-guided treatment was interpreted by many as being better able to spare erectile function as well as continence. The publication of the 5-year (medium term) results involving a cohort of 569 patients at University College London Hospitals and seven other British centers reveals disappointing sexual outcomes. The study included primary intervention using HIFU as well as re-do HIFU.
Patient ages ranged from 47-87, with the average (mean) age of 65. One hundred sixty-three patients (29%) required a total of 185 repeat HIFU treatments, for a total of 754 treatments. Of those who completed the study and follow-up, there were 161 low-risk patients (28%), 321 intermediate risk (56%) and 163 high risk (14%). Median follow up was 46 months. The 5-year failure-free (no rise in PSA) rates were
Low risk: 87% failure free. Intermediate risk: 63%. High risk: 58%. The main urinary side effects for the total 754 treatments were as follows:
A single urinary tract infection – 58 (7.7%)
Recurrent urinary tract infection – 22 (3%)
The authors report, “Of 206 known to be pad-free pre-HIFU, 183/206 (88%) remained pad free, and of 236 with good baseline erectile function, 91/236 (39%) maintained good function. The main limitation is lack of long-term data.” The researchers note that while cancer control was “acceptable” and there was low risk of urine leakage following treatment, the ED rates were “similar to other whole gland treatments.”
Perhaps one reason for 61% percent experiencing post-HIFU sexual dysfunction has to do with ultrasound guidance. While ultrasound reveals the contours and size of the gland, the fine details of the location of the neurovascular bundles are obscured. This helps explain why the top robotic surgeons have higher rates of nerve-sparing success, since they are able to directly observe the highly magnified anatomy (which differs slightly from one patient to another).
Although most HIFU will continue to be done under ultrasound guidance, there is a ray of hope. A new approach called MRgFUS (Magnetic Resonance-guided Focused Ultrasound) uses real-time multiparametric MRI to reveal the anatomy of the gland and the functional tissue characteristics that define the location, size, shape and aggressiveness of the tumor. According to Zini et al. (2012), “This advantage makes MRI the more suitable technique [over ultrasound] for targeting focal cancer lesions in the prostate. In addition, MR thermometry enables the operator to monitor the temperature and amount of estimated tissue damage real time both at the site of ablation as well as in vulnerable areas that have to be protected from ablation.
Not only will MRgFUS be able to identify and avoid the neurovascular bundles (as clinically appropriate given tumor location) but it is completely noninvasive since there is no transrectal probe. The crystal array that delivers precise sound energy is actually in the table on which the patient lies, and which slides in and out of the bore (tunnel) of the magnet. In fact, at our Center we are excited about the possible benefits of MRgFUS, and are vigilant in tracking developments in this technology since we anticipate offering it.
To sum up, the current HIFU device systems that incorporate transrectal ultrasound guidance appear to deliver cancer control and side effect results similar to other whole gland treatments such as prostatectomy and radiation. While this may be disappointing for the present, we believe there is hope for the future thanks to multiparametric MRI.
Copyright by Dan Sperling, MD. Reprint permission courtesy of Sperling Prostate Center (New York, Florida), the leading U.S. Center for multiparametric detection, diagnosis and image-guided focal treatment of prostate cancer.
Read more in our Prostate Cancer Health Center.
Dickinson L et al. Medium-term outcomes after whole-gland high-intensity focused ultrasound for the treatment of nonmetastatic prostate cancer from a multicentre registry cohort. Eur Urol 2016 Oct; 70(4): 668-74
Zini C et al. Ultrasound- and MR-guided focused ultrasound surgery for prostate cancer. World J Radiol 2012 Jun 28; 4(6): 247–52.