In October 2015, the U.S. Food and Drug Administration (FDA) approved the first ultrasound system for the ablation of prostate tissue in the United States. This new treatment called high-intensity focused ultrasound or HIFU, is a technology using ultrasound waves to destroy cancerous tissue found in the prostate gland.
HIFU works by transmitting mechanical force via ultrasound waves which generate heat to the malignant tissue. Because the prostate is deep within the pelvis, it uses a probe placed into the rectum that gives out a beam of ultrasound waves. This allows HIFU to accurately direct the beam at the area of where the cancer is located in the prostate, ablating the tumor.
Initially blocked for approval
Questions surrounding the safety, lack of information and deficiencies had been the holdup of FDA approval in the past. HIFU had been approved by other countries where more than 50,000 men had been treated with the procedure, causing some American men to travel outside the country for treatment. But now that it’s approved, doctors are able to offer it as a noninvasive option which can selectively target and treat tumors, while preserving surrounding healthy tissue.
Use of HIFU has certain specifications
HIFU is not a new technology in cancer treatment. The technology has been used in breast, liver, kidney, pancreatic and bone malignancies before. However, with a 99 percent 5-year survival data in current prostate cancer treatments with surgery, the technology has to offer excellent survival data along with low complication rates to compete with the current standard of care in practice, robotic prostatectomy.
Proper case selection is the most significant factor in considering HIFU as a treatment option. Like any cancer diagnosis, there needs to be an individualized care plan to best meet the needs of the patient. Eligibility for HIFU treatment depends on whether a man has low-grade cancer that has not spread outside the prostate gland.
Patients with enlarged prostate are not considered eligible for HIFU treatment, and the treatment can take up to 10 hours to perform. Currently research suggests that older patients who cannot tolerate surgery or patients diagnosed at the earliest stages of the prostate cancer (Gleason 6) should be asked if they prefer HIFU as an option.
Advantages and disadvantages of HIFU
The advantages of HIFU are its minimally invasive nature combined with a short hospital stay. Recent studies have shown that 94 percent of men with early stage prostate cancer treated with HIFU had eradication of all clinically significant cancer in the treated area. And in 87 of 101 cases, patients saw complete ablation of all cancer in the prostate.
When the men were followed up two years later, 89 percent were still alive without radical therapy. Almost all of the men had resolved any urinary incontinence and about 80 percent had preserved erectile function.
But it’s important to remember that two years is not an adequate amount of time to evaluate the efficacy of prostate cancer treatment, as previous data has suggested higher recurrence rate in patients undergoing HIFU. Other studies have shown 36- to 47 percent biochemical recurrence (rise in PSA level) in patients undergoing HIFU after 5 years. Considering the fact that untreated parts of the gland could potentially undergo malignant changes as well in time, the recurrence rate might be higher in patients who survive more than 10 years after diagnosis.
The disadvantages of HIFU include possible scarring of the prostate, a recurrence rate which is not well understood, and the cost. According to a review article published in Journal of Cancer, 19.7 percent patients undergoing HIFU for prostate cancer treatment can end up with urethral strictures and up to 6.2 percent can be complicated with epididymitis. The current data on HIFU, considering the quality of the evidence and length of follow up times in treatments are not satisfactory to consider it as a standard treatment option in a routine practice. However, cautiously selected patients can be offered to undergo HIFU, if requested.
The decision to use HIFU or not is between the patient and his doctor to decide. Weighing the pros and cons is an important step before any decision is made on using HIFU for treating prostate cancer.