MIRS Special Report

New Treatment for Uterine Fibroids Avoids Surgery

Introduction

Uterine fibroids are the most common pelvic tumors in women, occurring in approximately 30% of women over the age of 35. Although fibroids are benign (non-cancerous), they may produce a wide variety of symptoms including excessive bleeding leading to iron deficiency anemia, pain and pressure sensations, and even obstruction of the bowel or urinary tract. Women with fibroids often complain of painful intercourse, and the presence of fibroids may result in pregnancy loss. Each year, approximately 200,000 hysterectomies are performed in the United States for uterine fibroids. Despite this large number of operations, the vast majority of women with symptomatic fibroids are "silent sufferers".

Until recently, the only effective treatments for fibroids were hormonal therapy and surgery. Because fibroids grow in response to the female hormone estrogen, anti-estrogen hormones such as progesterone can shrink fibroids and may result in dramatic improvement in symptoms. However, these hormones have many untoward side effects including menopausal symptoms and osteoporosis (softening of the bone). Consequently, hormonal therapy can only be used for a short time and, unfortunately, once it is discontinued, symptoms usually return. Therefore, hormonal therapy is most useful in shrinking fibroids prior to surgery.

There are two general types of surgery available for fibroids, hysterectomy and myomectomy. Hysterectomy is the complete removal of the uterus with or without removal of the ovaries. In some cases hysterectomy can be performed through the vagina, avoiding an incision through the abdominal wall. However, with large fibroids, an abdominal hysterectomy (that is, a hysterectomy through an abdominal wall incision) is often necessary. Abdominal hysterectomy is a major surgical procedure requiring general anesthesia, approximately 6 days of hospitalization, and at least 6 weeks of recuperation. Obviously, pregnancy is no longer possible following a hysterectomy.

Myomectomy is an alternative surgical procedure for the treatment of fibroids. The object of myomectomy is to remove only the fibroid while leaving the uterus intact and preserving reproductive potential. Depending on the location and size of the fibroid, myomectomy may require an abdominal incision or may be done through a laparoscope (a telescope-like instrument inserted through an abdominal wall puncture) or a hysteroscope (a telescope-like instrument inserted through the vagina). With larger fibroids, attempted myomectomy frequently results in hysterectomy due to uncontrollable bleeding in these highly vascular tumors. Even when successful, myomectomy offers only temporary improvement in about one-third of patients because smaller untreated fibroids continue to grow.


Uterine Artery Embolization

Embolization (embolotherapy) is a procedure used to block blood vessels from the inside. Embolotherapy is performed by Interventional Radiologists, physicians who specialize in the treatment of a variety of diseases using catheters (tiny tubes) and medical imaging techniques. For nearly thirty years, embolotherapy has been used as a means of stopping uncontrollable bleeding from the uterus due to cancer, blood vessel malformations, trauma, and complications of pregnancy. In the early 1990's, investigators in France began using embolotherapy of the uterine arteries to prevent excessive bleeding in women about to undergo myomectomy for uterine fibroids. A surprising and wholly unexpected result of these uterine artery embolization procedures was that many of the patients had such significant improvement in their symptoms that surgery was postponed. Over the course of months it became clear that the improvement noted in these women was not only significant, it was durable. Consequently, a pilot study was begun to evaluate the long-term results of uterine artery embolization for the primary treatment of fibroids.

In the initial pilot study, 85% of women undergoing uterine artery embolization experienced significant improvement or complete resolution of symptoms. In 75% of cases the size of the uterus decreased by 20-80% within 3 months, and these results remained stable with an average follow-up of more than 18 months (11 to 38 months). In a second study from UCLA, 77% of patients reported "significant improvement" or "complete resolution" of their dominant fibroid symptom at 2 to 9 months follow-up. In this group, 2-month follow-up revealed an average 40% (22-61%) reduction in uterine volume with the dominant (largest) fibroid decreased by an average of 58% in 55% of the patients studied. In one-third of the patients the fibroids were no longer visible by ultrasound.

On the basis of these studies, uterine artery embolization programs for the non-surgical treatment of fibroids have been established at several academic medical centers in the United States. The experience gained at these centers will optimize treatment protocols and provide in-depth answers to questions regarding the durability of symptomatic relief and preservation of reproductive function.


The Uterine Artery Embolization Procedure

The uterine artery embolization procedure is performed by an Interventional Radiologist in the radiology department of the hospital. Although patients are awake for the procedure, they are sedated and often have no recollection of events during the embolization. The procedure itself consists of introduction of a tiny tube (catheter) into an artery in either the left arm or the groin under a local anesthetic. Except for the injection of the local anesthetic, there is little or no discomfort associated with the catheter insertion. Once in the artery the catheter is manipulated into the uterine arteries and angiography is performed. Patients may experience a mild sensation of warmth during the angiogram. When the catheter is positioned well within the uterine artery, tiny pellets of a material called PVA are injected. (Note: the chemical name for PVA is polyvinyl alcohol, but it is neither vinyl as in flooring nor alcohol as in alcoholic beverages. It is merely an organic [i.e., carbon-based] synthetic compound with properties that make it a useful embolic agent.) The PVA is carried by the flow of blood into the uterus and all of the fibroids present. The particles eventually impact in the very small arteries and produce blockage. Deprived of their blood supply, the abnormal cells in the fibroids die and are slowly removed by the body. Meanwhile, the body restores circulation to the normal tissue by both the in-growth of new arteries and the removal of a portion of the PVA from some of the existing vessels.

Immediately following the embolization procedure the catheter is removed and pressure is applied to the entry site for about 15 minutes to stop any bleeding. Almost all patients experience crampy abdominal pain following the procedure. Consequently, we provide patients with on-demand pain medicine through a device called a PCA (patient controlled analgesia) pump. Many studies have demonstrated that patients experience far less pain, yet actually use far less pain medication when this device is used. Patients are admitted to the hospital overnight and can usually be discharged home the morning following the procedure. Most patients can return to work within a few days. At the current time, we ask patients to return for an ultrasound examination two weeks and two to three months after the procedure to assess results. The patient will also be asked to complete a short mail-in questionnaire one year after embolization. Additional follow-up may be requested in the future.

Clinical Examples

Below left: Angiogram before (top) and after (bottom) uterine artery embolization in a 43 year old woman with a cantaloupe-size uterine fibroid. A large number of abnormal arteries supply the mass. Following embolization there is no blood flow to the tumor. The patient had suffered moderate abdominal discomfort and severe vaginal bleeding with iron deficiency anemia for two and one-half years. Two months following embolization there was a 60% reduction in the volume of the mass and all symptoms had resolved.

Below: Sonogram in a 37 year old patient before (top) and 2 months after (bottom) uterine artery embolization. The grapefruit-size uterine fibroid is barely visible on the follow-up study and the patients pain and abnormal bleeding have completely resolved.



Frequently Asked Questions Regarding Uterine Artery Embolization

What are the risks associated with uterine artery embolization?

The potential risks of the procedure include bleeding from the catheter entry site, infection, adverse reactions to medications or contrast media, blood vessel injury, inadvertent embolization of other tissues. The risk of a significant complication is less than 0.5%.

Does uterine artery embolization result in significant clinical improvement?

In all studies to date, embolization has resulted in significant improvement or resolution of symptoms in more than 75% of patients treated. With improvements in technique, it is anticipated that perhaps 90% of women treated will have substantial improvement in symptoms.

What impact does uterine artery embolization have on reproductive function?

Most studies published thus far have focused on women who did not desire pregnancy. However, pregnancies have occurred and been carried to term following uterine artery embolization for fibroids. Small studies of women who underwent uterine artery embolization to control bleeding complications of labor and delivery have shown the return of normal menses within a few months in all cases and all women desiring subsequent pregnancy conceived and were successful in carrying to term. Since the presence of fibroids already has a negative impact on pregnancy, determining the impact specific to embolization will be difficult and will require a very large number of patients.

Does uterine artery embolization preclude other potential treatments?

In the setting of uterine fibroids, this procedure began as a preoperative measure to control bleeding during myomectomy. Preoperative embolization is commonly used in a variety of settings because it makes surgery easier and safer. Since the only other definitive treatment for fibroids is surgical at this time, the only impact embolization would have on such treatment is complementary.

Is uterine artery embolization cost-effective compared with conventional therapy?

The overall procedure cost is significantly less than abdominal hysterectomy and moderately less than hysteroscopic and laparoscopic myomectomy. When one takes into account the potential economic losses during a 6-week recovery from abdominal hysterectomy, the cost differential becomes astronomical.

Are results obtained with uterine artery embolization durable?

Published reports have shown stable results with follow-up of more than 3 years in a few cases. For women approaching menopause, the results may well be permanent since estrogen production is declining and estrogen is required for fibroid growth. There is insufficient data at this time to predict the long-term durability in younger patients because estrogen secretion will continue for many years and, theoretically, may stimulate the formation of new fibroids. It may be several years before sufficient data is compiled to assess long-term results in younger patients. On the other hand, if fibroids do recur after several years, it should be possible to treat them with repeat embolization.

Where can I find more information about uterine artery embolization?

You should first discuss this procedure with your primary care physician or gynecologist. Unfortunately, many physicians are unaware of this alternative treatment for fibroids despite the fact that this procedure has now been used to treat well over a thousand patients in the United States. For specific information on this procedure you should contact an Interventional Radiologist in your locale. For Kansas, Missouri, Arkansas, Oklahoma and adjacent areas of neighboring states you may find a local Interventional Radiologist in the MIRS Physician Listings. Additional information and Interventional Radiologists in other locales can be found at the Society of Cardiovascular and Interventional Radiology (SCVIR) site on the World Wide Web.

Submitted by Edward L. Siegel, MD, Department of Radiology, University of Kansas Medical Center, 10/99