Diagnostics & Imaging Week

CHICAGO – Women who suffer from uterine fibroids may have an effective option for removing them non-invasively, based on a study presented during the Radiological Society of North America (RSNA; Oak Brook, Illinois) annual meeting at McCormick Place earlier this month.

The option is a non-invasive procedure using high-intensity ultrasound waves to “heat and destroy uterine fibroid tissue” using magnetic resonance-guided, focused ultrasound surgery (MRgFUS), which the study’s authors suggest allow radiologists to “precisely” target fibroids without harming healthy surrounding tissue.

“[This is] a very debilitating disease,” said the study’s lead author, Fiona Fennessey, MD, PhD, instructor of radiology at Harvard Medical School and staff radiologist at Brigham and Women’s Hospital (both Boston) at a press conference to discuss the study’s findings, later adding, “Women are becoming more and more aware of non-invasive options.”

For example, she said although fibroids are benign growths in the muscle inside the uterus, they cause increased bulk in the uterus, which puts pressure on the bladder, often causing frequent urination and back pain, in addition to excessive menstrual bleeding.

Currently, hysterectomy is the “gold standard” for treatment of uterine fibroids; however, in recent years women have begun to search for other options, which include fibroid embolization, fibroid ablation and myomectomy, in which only the fibroids themselves are surgically removed.

For example, according to RSNA/American College of Radiology (ACR; Bethesda, Maryland) resources, uterine fibroid embolization involves “using angiographic methods similar to those used in heart catheterization, a catheter is placed in each of the two uterine arteries and small particles are injected to block the arterial branches that supply blood to the fibroids. The fibroid tissue dies, the masses shrink, and in most cases symptoms are relieved.”

According to the National Institutes of Health (NIH; Bethesda, Maryland), at least 25% of women in the U.S. age 25 to 50 suffer from fibroids, and as many as 50% of African-American women have uterine fibroids.

And according to the National Women’s Health Information Center, fibroids are the primary reason for hysterectomy, accounting for 175,000, or about one-third, of hysterectomies performed annually in the U.S.

In their study of MRgFUS, Fennessey and other researchers looked at 160 women with symptomatic fibroids as part of a clinical trial at five medical centers.

With the procedure, MRI is used in pre-treatment to determine the exact location of the fibroids, she said. During the procedure, the woman must lie “belly down” over a transducer that is actually in the table of the MRI equipment, and the sound waves are then targeted with the MRI at the fibroids, which are directly above the transducer.

“Before we treat, we make sure nothing is between the fibroids [and the transducer] with MRI,” she said, such as ensuring that no part of the bowel is in front of the fibroids.

Of the 160 women – all of whom were required for the study to have no desire for future pregnancy – 111 were treated under the original study protocol, or Protocol A, and 51 patients were treated with an optimized protocol, or Protocol B.

Protocol A allowed a maximum treatment time of 120 minutes or a maximum treatment volume of 100 cc, or up to 33% of total fibroid volume. Protocol B allowed a maximum treatment time of 180 minutes, or up 33% of total volume of fibroids on the outer wall of the uterus and 50% volume in fibroids elsewhere in the uterus.

Fennessey said that the researchers found that the “greater the fibroid volume treated, the better the outcome,” up to p<0.0001, which is highly significant.

She said the sound waves shrink the fibroids, but do not totally destroy them. “The goal is not to destroy the fibroid, because this is not surgery, but [to create] dead tissue in the center so that the fibroid will collapse in on itself,” she noted.

The study reported no serious adverse events.

This type of MRgFUS treatment is available now through the ExAblate200 from Insightec (Tirat HaCarmel, Israel), she said.

Treatment outcomes were assessed by the Uterine Fibroids Symptoms and Quality of Life scores obtained at baseline, three, six and 12 months post-treatment.

Protocol A with percentage of patients with significant improvement was 76.5% at three months, 76.9% at six months, and 75.8% at 12 months.

With the expanded Protocol B, 86.4% had significant improvement at three months, 85.7% at six months and 85.7% at 12 months.

And treating benign uterine fibroids likely is not the only way ultrasound can be used with MRI, Fennessey suggested. “Probably you will see papers in the future on ultrasound with malignant tumors,” she said.