High Intensity Ultrasound for the Treatment of Prostate Cancer

INTRODUCTION

Medical science has taken significant leaps in the past three decades with the advent of a non-invasive approach to surgical investigation and treatment modalities.  This movement was greatly prompted by the need to reduce or eliminate the many significant risks and hidden dangers of cutting through the skin and vital organs.  Technologies such as the ULTRASOUND offers the medical community life-saving alternatives that ensures quantifiable results without the  potential dangers to the patient. (also see "No More Scalpel" and "Bye Bye Biopsies")

Pursuing the concept of safe, non-surgical alternatives, the principle of HIFU is based on controllable high energy sound waves, which leads to coagulation necrosis at the focal point. It can be applied for different indications: complete ablation of prostatic tissue is attempted in whole gland HIFU in the primary treatment of localized prostate cancer. [1] The first therapeutic trial of high intensity ultrasound beams was carried out in 1942. The Fry brothers are credited with the first application of HIFU for neurologic disorders in humans. Early attempts to generate HIFU lesions in the brain through the intact skull bone were unsuccessful. Jan 10, 2011 [2]

HIFU: THE NEXT WAVE OF NON-INVASIVE CANCER TREATMENT 
By: Dr. Robert L. Bard 

Prostate cancer, certainly the most common cancer among men, might be considered a two-headed hydra. On the one hand, some of these tumors, especially among African-Americans are aggressive, resulting in premature death. On the other hand, many of these tumors are slow growing and for a significant subset of patients, watchful waiting is recommended. But it is difficult to watch and wait when you believe that a cancer is growing within.

The quest for minimally invasive treatments of prostate tumors has been ongoing since the 1990’s. There have been advocates of focal freezing as well as heating of prostate tissue that results in the destruction of prostate cancers. Focal cancers may be targeted by high intensity focused ultrasound beams (High Intensity Focused Ultrasound or HIFU) and have been in clinical practice for 25 years. Developed simultaneously in the US (Sonoablate 500) and France (Ablatherm) the technique is favored by men wishing to avoid possible complications or side effects of surgery or radiation therapy. 

Treatment is usually performed under anesthesia. Energy is delivered to malignant tissue using in this instance, high frequency ultrasound waves that heats the tissue above 40 degrees Centigrade destroying the tissue.  Tissue temperature is closely monitored by sophisticated electronics to minimize adjacent tissue damage which can result in narrowing of the urethrae and obstruction of the flow of urine. Additionally, nerves involved in sexual performance may be inadvertently heated resulting in some degree of sexual dysfunction. 

A recent study reported in the Journal of Urology looked at 52 patients treated with this technique. The results are mixed. Patients included all had localized biopsy proven prostate cancers. The study defined treatment failure as recurrence on follow up biopsy at 20 months showing recurrent or higher grade tumor, metastatic spread systemic therapy or cancer specific mortality. 

• There were 13 minor complications of which urinary retention was the most common.  There were no deaths and no cases of rectal injury.

• Of the 60% of individuals undergoing repeat biopsy, 83% had no residual tumor

This study was limited in two significant ways. First, nearly a quarter of the patients underwent simultaneous “debulking” of prostate tissue by conventional surgical means in order to treat pre-existing difficulties with urination. Second, if biopsy is to be considered the outcome of importance, then 40% of the patients did not complete the study.

It did not recognize that microscopic analysis of biopsies is limited by the posttreatment effect on the gland and the gold standard for pathology has been whole gland analysis after radical prostatectomy.

VIEWPOINTS:
Treatment will be more effective on smaller volume glands and low grade cancer. As an imaging specialist, the problem with biopsies is that the cells under the microscope may look malignant but the tumor is clinically indolent or inactive. Biopsies are random and the area presumed to be a cancer may have active malignancy in one area, scarring in another, benign tissue adjacent or immune cells attacking the injured tissue.  Most post treatment biopsies are guided by blood vessel flow study with contrast MRI or 3D Doppler in the cancer site since PSA is not very reliable. The targeted area is the region of greatest arterial tumor arterial concentration.  [J Urol 2016]

Worldwide the aggression of a tumor is determined by the activity of the feeding blood vessels. Generally ablative treatments are deemed successful when there are no more arterial suppliers demonstrable by the various blood flow perfusion imaging technologies (Doppler ultrasound, CT dye, MRI contrast)  It is well known that there is a PSA rise in the presence of inflammation as well as recurrence which is non diagnostic. Over many years the cancer statistics observed that the re-occurrence of malignancy in 5 years falls between 10-30% regardless of the treatment delivered.

About the Author:

Dr. Robert L. Bard currently runs a private cancer imaging center in NYC specializing in advanced 3-D sonography to detect cancer tumors and other health disorders.  He lectures in medical conferences worldwide, runs a cancer awareness program for first responders and is also a publisher of countless educational books and articles about cancer imaging and other health/wellness related materials. Dr. Bard maintains an active role in supporting the medical community by contributing relevant articles to major health magazines, medical journals and news organizations pertaining to current health concerns. His recent projects include advocating and inserting TELEMEDICINE in the medical community as a safe alternative for patients.  Other projects include an upcoming collaborative textbook series on Covid-19 with a list of top experts in the field.  Dr. Bard is also the president of the AngioFoundation (501c3), as philanthropic organization dedicated to funding and supporting public education about current treatment protocols worldwide. 

REFERENCES

1) High intensity focused ultrasound (HIFU) : Importance in the treatment of prostate cancer https://pubmed.ncbi.nlm.nih.gov/28439616/#:~:text=Results%3A%20The%20principle%20of%20HIFU,treatment%20of%20localized%20prostate%20cancer.

2) High intensity focused ultrasound in clinical tumor ablation - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3095464/#:~:text=HIFU%20BACKGROUND-,History,unsuccessful%5B8%2C10%5D.

Sources: Prospective Evaluation of Focal High Intensity Focused Ultrasound for Localized Prostate Cancer Journal of Urology DOI: 10.1097/JU.0000000000001015

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