Men with ‘intermediate risk’ prostate cancer may be able to avoid surgery, chemotherapy and radiation, thanks to a new method of treatment.
The new approach uses high-intensity focused ultrasound (HIFU) guided by magnetic resonance imaging (MRI) to destroy small tumours confined to one area of the prostate with little to no side effects.
At Memorial Sloan Kettering Cancer Center (MSK), researchers have been working closely with the advanced focal therapy approach.
A phase two trial, led by MSK urologic cancer surgeon Behfar Ehdaie, looked at a particular type of HIFU treatment, also called MR-guided focused ultrasound, in men with intermediate-risk cancer.
“We believe this novel treatment strategy will improve the lives of many prostate cancer patients,” Dr Ehdaie said.
“To draw a parallel with how breast cancer treatment changed 30 years ago, you could think of focal therapy as a ‘male lumpectomy’.
“Instead of removing all the tissue in a breast or prostate, we have learned that it is safe and effective to treat specific areas and greatly reduce the burden on patients.”
Past treatments
When the cancer is confined to the prostate gland, the main treatment options have traditionally included active surveillance, surgery and radiation.
But men who needed surgery or radiation often had persistent side effects, such as urinary and sexual problems, that could reduce quality of life.
“Advancements in prostate cancer over the past two decades have been headlined by successes that have benefited all patients, and now focal therapy provides another exciting area that can move the needle in prostate cancer management,” Dr Ehdaie said.
Results from the clinical trial, published on June 14 in Lancet Oncology, represent a major step toward having the new HIFU approach become part of widespread prostate cancer treatment.
Focused ultrasound
The MR-guided focused ultrasound is an outpatient treatment that takes about two hours.
Patients under anaesthesia are placed in an MRI machine that covers the lower half of the body.
After the machine takes an image of the prostate, the doctors outline the treatment area and deliver the focused ultrasound waves, guided by the MRI.
The ultrasound waves come from different directions, intersecting to attack and kill the cancer by heating the cells to more than 158 °F (70 °C).
“While you are imaging, you are getting temperature feedback as well to make sure the right spots are being treated,” Dr Ehdaie said.
“The patient wakes up from the anesthesia and goes home. There’s no incisions or wounds on the body to heal.
“We have demonstrated the procedure is safe for patients, and they can return to normal activity right away.”
More availability
Dr Ehdaie said that using MRgFUS for intermediate-risk cancers became possible due to two important developments over the past 15 years.
First, there was an acceptance by experts of using active surveillance for low-grade tumours.
The second advance was new imaging technology that enabled MRIs to be incorporated into ultrasound treatment.
In the phase two clinical trial, 101 men received the novel MR-guided focused ultrasound treatment and then were biopsied six months and 24 months later.
There was no intermediate- or higher-risk cancer left in the treated area for 88 per cent of the patients.
“Probably most important was the lack of side effects,” Dr Ehdaie said. “Nobody in the study reported urinary incontinence or experienced bowel problems. Most men were able to achieve erections.”
Based on this data, the FDA in December 2021 granted approval for the technology, called Exablate Prostate, to treat prostate tissue.
The FDA also approved an investigator-initiated trial designed by Dr Ehdaie and surgeon Peter Scardino to compare MRgFUS focal therapy to active surveillance and demonstrate a clinical benefit for patients with prostate cancer.
