For more than a generation, urologists have followed two basic treatment plans for men diagnosed with localized prostate cancer: active surveillance, the “wait and see” method, and radical treatment such as surgical removal of the entire prostate or radiation therapy.

Outside of these standards of care, other treatment modalities that focus on removing only the diseased portion of the prostate have been viewed with skepticism because of the size of the prostate, relative inaccessibility to the tumor and the fact that prostate cancer can appear in multiple places within the prostate (it’s multifocal).

Yet, at one time doctors considered removing only the cancerous tumor in the breast for women with breast cancer a dangerous departure from the standard of care, which was radical mastectomy. Of course, today lumpectomy is a conventional therapy that has preserved the health related quality of life (hrQoL) for so many women.

Prostate cancer, which is similar to breast cancer in many ways, was considered a poor candidate for a “lumpectomy” (or focal therapy) until the U.S. Food and Drug Administration (FDA) cleared High Intensity Focal Ultrasound (HIFU) in 2018 as focal therapy for prostate disease. HIFU has been used for decades in Europe with excellent long-term outcomes and minimal side effects of impotence and incontinence.

High Intensity Focal Ultrasound
What follows is a comprehensive overview of HIFU – what the treatment is, how it works, reference to several clinical studies and what patients can expect before, during and after the HIFU procedure.

High-Intensity Focused Ultrasound (HIFU) is a minimally invasive treatment for localized prostate cancer that uses high-frequency sound waves directed at cancerous tissue through an ultrasound probe inserted into the rectum. The high intensity sound waves heat up and destroy the targeted tissue, causing cell death.

This minimally invasive treatment combines magnetic resonance imaging and biopsy data with ultrasound guided imaging to enable doctors to precisely target and destroy only the diseased portion of the prostate, and spare surrounding healthy structures.  HIFU is significant because of the degree of precision with which the cancer can be treated in the prostate; sparing healthy tissue and thereby minimizing the risk of urinary continence and erectile dysfunction.

An appropriate alternative
For patients with localized prostate cancer HIFU may be an appropriate alternative to standard treatments, including radical prostatectomy and radiotherapy. Also HIFU can be repeated if the cancer returns, unlike radical surgery and radiation.

HIFU has been used for whole gland ablation or partial gland ablation of localized prostate cancer, depending on the grade and stage of the cancer, and treatment needs of the patient.  Partial gland ablation, also referred to as focal therapy, has been compared to the lumpectomy for breast cancer.  Due to improvements in MRI visualization and biopsy data, and the ability to better localize the prostate tumor, partial gland ablation makes it possible to pinpoint and remove only the cancerous tissue, and spare normal tissue.

Encouraging results
Since the late 1990s, HIFU has been used to treat more than 60,000 men around the world (and approximately 3,000 men in the U.S.) with encouraging results in terms of both survival rates and quality of life. In 2015, the FDA approved HIFU in the U.S. for the ablation of prostate tissue.  HIFU is considered in the early stage of development in the U.S., and not a standard of care, since 10-year studies are not yet available.  Several US academic institutions are currently accumulating treatment data on American patients.

However, two long term studies based on whole gland ablation, have been published in France and Germany (2013).  In the French study, 1,002 patients were treated with HIFU for localized prostate cancer from 1997 to 2009. The results of the study showed: “At 10 years, the PCa-specific survival rates and metastasis-free survival rates were 97% and 94%, respectively.” [1]

The German study results of 704 patients with a mean follow up of 5.3 years, showed cancer specific survival of 99%, metastasis-free survival of 95%, and 10-year salvage treatment-free rates of 98% in low risk, 72% in intermediate risk and 68% in high risk patients.[2]

More recently, two different studies of HIFU for partial gland ablation were published in the U.K. in 2018 and 2019.  The first is a multicentric study of 625 patients with a median follow-up of 56 months showing metastasis-free, cancer-specific, and overall survival rates at five years of 98%, 100% and 99% (Guillaumier et al.). The second study included 1,032 patients and showed overall survival rates at 24, 60 and 96 months of 99%, 97% and 97%, respectively. [3][4]

About the Procedure
The HIFU procedure is generally performed in a single session on an outpatient basis, requiring no hospital stay. It typically takes between one to three hours. Treatment is usually performed under general anesthesia, but spinal anesthesia is sometimes used.

In the procedure, a probe is inserted through the rectum and produces a detailed, 3D image of the prostate – showing the entire organ and the cancerous areas. The urologist draws a contour around the diseased tissue and the targeted area is then ablated with high intensity ultrasonic waves using the same probe. The area destroyed by each wave is very precise. The robotic device repeats the process by locating the next focal point and destroying only the cancerous tissue in the prostate.

Advantages of HIFUDisadvantages of HIFU
No incision is requiredHIFU treats only the areas targeted for ablation. However, the cancer can reoccur in another area, although the HIFU procedure can be repeated
The patient does not undergo any radiation exposureRisk of major complications include: urinary tract infection, urinary retention, sexual dysfunction, urinary incontinence, urethral stricture and recto-urethral fistula
Treatment can be repeated if necessaryPayment by insurance companies varies.  Without any coverage the procedure is approximately U.S. $25,000.

Medicare offers partial reimbursement and the American Medical Association has approved issuance of a CPT code for HIFU, starting January 1, 2021.

CPT codes are used by private insurers and Medicare to reimburse patients for the procedure)

Other therapeutic alternatives can be considered in case of incomplete results or if the cancer returnsWhile studies in Europe and preliminary studies in the U.S. point to the effectiveness of HIFU, longer term follow up of a larger patient population is still needed in the U.S. to accept HIFU as a standard of care for men with localized prostate cancer
HIFU can be used for the treatment of local recurrences (i.e., after external beam radiotherapy)

 

Who is a Candidate for HIFU?
Ideal candidates for HIFU are those who have early stage (Gleason 6 or 7), low- or intermediate-grade cancer that is confined to the prostate, and that is visible on an MRI. A PSA level below 20ng/mL is also preferred. HIFU is used to treat a single tumor or part of a large tumor and is not meant for those whose cancer has spread beyond the prostate.

Reference
[1] Crouzet S, Chapelon JY, Rouvière O, et al. Whole-gland ablation of localized prostate cancer with high-intensity focused ultrasound: oncologic outcomes and morbidity in 1002 patients. Eur Urol. 2014;65(5):907–914. doi:10.1016/j.eururo.2013.04.039 [Pubmed][Article]
[2] Thüroff S, Chaussy C. Evolution and outcomes of 3 MHz high intensity focused ultrasound therapy for localized prostate cancer during 15 years. J Urol 2013; 190:702-10. [Pubmed][Article]
[3] Guillaumier S, Peters M, Arya M, et al. A Multicentre Study of 5-year Outcomes Following Focal Therapy in Treating Clinically Significant Nonmetastatic Prostate Cancer. Eur Urol. 2018;74(4):422–429. doi:10.1016/j.eururo.2018.06.006 [Pubmed][Article]
[4] Stabile A, Orczyk C, Hosking-Jervis F, et al. Medium-term oncological outcomes in a large cohort of men treated with either focal or hemi-ablation using high-intensity focused ultrasonography for primary localized prostate cancer. BJU Int. 2019;124(3):431–440. doi:10.1111/bju.14710 [Pubmed][Article]