Magnetic Resonance-Guided Focused Ultrasound Surgery Offers Scalpel-Free Alternative to Standard Prostate Cancer Treatments
When detected early, clinically significant prostate cancer has one of the lowest mortality and malignancy rates in comparison to other types of cancer, but the treatment options available can often be a double-edged sword. Uncomfortable side effects, such as urinary incontinence, rectal toxcity and erectile dysfunction, can occur following standard treatments, which include radiation and surgical removal of the prostate. These potential complications are unappealing to patients, as they can significantly decrease their quality of life.
The close proximity of the prostate gland to other parts of the body, including the bladder, rectum and penis, makes the treatment of prostate cancer a difficult process that requires the utmost precision; alterations to the gland – such as partial or complete removal of it or hormone therapy targeted at it – can easily affect the functionality of the surrounding organs. Current treatment options focus on treating the whole gland using methods that range from hormone therapy to radiation to a complete prostatectomy (removal of the prostate). All of these techniques run the risk of causing urinary, sexual and gastrointestinal dysfunction.
Pioneering a Better Method
To treat prostate cancer patients while lowering the risk of side effects, a multidisciplinary team of researchers and clinicians at BWH pioneered a more targeted treatment. A team from the BWH Focused Ultrasound Laboratory, established in the early 1990s by Ferenc Jolesz, MD, and Kullervo Hynynen, MSc, PhD, and now led by Nathan McDannold, developed magnetic resonance-guided focused ultrasound (MRgFUS) and has continued to improve on ultrasound techniques since then. MRgFUS has been used to treat growths, such as uterine fibroids, but never prostate cancer. Earlier this year, a team led by Clare Tempany, MD, director of the National Center for Image-Guided Therapy in the Department of Radiology at BWH, and Adam Kibel, MD, chief of the Division of Urology in the Department of Surgery at BWH, became the first clinicians on the East Coast to apply MRgFUS to the prostate. This was performed as part of a clinical trial with InSightec Ltd, the device manufacturer.
Paul Cassidy, the patient who underwent this inaugural procedure at BWH, was diagnosed with stage 1 prostate cancer in November 2014. Before undergoing the procedure, Cassidy’s doctors monitored the development of his cancer using “active surveillance,” meaning that they would check in regularly to see if the cancer had progressed, and they would hold off on implementing any therapies. Cassidy wanted to approach his cancer more aggressively, but was wary of undergoing surgery or radiation, as these options would have likely decreased his quality of life.
“I was being fairly stubborn in terms of what I would and wouldn’t do,” said Cassidy. “There are all kinds of problems that treatments like radiation could cause with the body’s organs.”
When Kibel approached him with a new, less-invasive option, Cassidy agreed to be the first patient at BWH to undergo this procedure for prostate cancer.
“Being the first patient can be good and bad, but I always trusted Dr. Kibel,” said Cassidy. “I’m glad I went to BWH for this.”
Cassidy underwent a rigorous screening process to ensure that he was a good candidate for this procedure. This included MRI imaging, the results of which Kibel and Tempany used to essentially map out the affected portion of the prostate gland and know exactly where to target the ultrasound waves. The procedure typically lasts an hour, but because Cassidy was the first patient, his care team spent two hours completing the process as an added precaution.
While the patient is in the MRI, Tempany and Kibel visualize the prostate gland on and identify its cancerous portions using the images. Then, with the help of Nathan McDannold, medical physicist, they aim the ultrasound waves at portions of the prostate until the cancer cells are eliminated. The high intensity and pinpoint accuracy of the beams heat up the cancer cells until they are destroyed (a process known as ablation). This can be directly seen during the treatment using MR images as a “heat map.” It can show the changes in temperature allowing the medical team to closley monitor the local tissue chanegs all during the procedure.
“We call this scalpel-less surgery,” said Kibel. “We are able to destroy the tumor using a noninvasive method that avoids any of the negative side effects that accompany typical prostate cancer treatments. This results in little to no pain or discomfort and a short recovery period.”
What sets this method apart, in addition to reduced side effects, is its accuracy. The diameter of the average prostate gland is a little over an inch. The cancerous portions of the prostate gland are a fraction of that size; in Cassidy’s case, the diameter of the target area was less than half an inch. The precision required to destroy only the cancerous cells, without affecting the rest of the prostate or the surrounding organs, is extremely difficult using hormone therapy, radiation therapy or surgery. MRgFUS can accomplish this precision because the focal point radius of the ultrasound waves is small enough to target tiny portions of the prostate at a time. Additionally, the clinicians can immediately see how effective the treatment is.
Tempany looks forward to transitioning prostate cancer treatment from approaches that treat the entire gland as if it were equally filled with equally agressive cancer, to approaches that are more focused, targeting only proven cancerous portions of the gland.
“This method allows treatment to span the duration of surgery and improve the lives of patients for the rest of their lives,” she said.
The MRgFUS clinical trial for focal prostate cancer is currently open for enrollment at BWH. Contact persons: Clare Tempany MD (PI), Adam Kibel MD, Quoc Dien Trinh MD (Co-Investigators) Sponsor: InSightec Ltd. in Haifa, Israel.