UFE credibility

The gynecological community remains steadfastly skeptical in the face of the benefits of uterine fibroid embolization (UFE) as opposed to surgery. Jean-Pierre Pelage will be furthering the clinical credibility of the procedure with his presentation on lowering the rate of fibroid recurrence at this year's CIRSE meeting.

Uterine fibroid embolization is fast gaining ground on its surgical counterparts, hysterectomy or myomectomy, as a safe, relatively non-invasive and effective alternative to the treatment of fibroids. Since its introduction in Hôpital Lariboisiere in Paris, there have been upward of 50,000 cases performed. Studies have shown that the procedure is associated with high clinical success rates of between 80 to 90%, reported reductions in uterine and fibroid volume of 50 to 70% and low complication rates.

While radiologists are enthusiastic about the procedure, some gynecologists still consider UFE as experimental. Although the short-term benefits of the procedure are becoming increasingly difficult to ignore, the lack of long-term data on recurrence is a sticking point. Follow-up in most UFE studies has been 24 months or less and many in the gynecological community consider that long-term studies on symptomatic outcome need to continue for them to assess how embolization fits into their surgical therapeutic options, particularly with reference to myomectomy.

Recurrence

The disadvantage of myomectomy is the risk of clinical recurrence, which is as high as 30-40% at three years. According to studies, most of these recurrent symptoms are not caused by new fibroids but related to the regrowth of fibroids left in place during the initial treatment. With embolization, symptom recurrence at two years is generally related to the regrowth of fibroids, which received insufficient initial devascularization. Therefore the goal of the interventional radiologist performing UFE is to attain complete ischemic infarction of all identified uterine fibroids to prevent any recurrence. "For the durable acceptance of uterine fibroid embolization as a valuable alternative to multiple myomectomy, we should have lower clinical recurrence rates than surgery at 2-3 years," says Pelage.

Causes of recurrence

One of the most common causes of fibroid recurrence after UFE, according to Pelage, is arterial spasm or flow restriction at the time of embolization. Another possibility is thin uterine arteries found in women who have received an injection of gonadotrophin-releasing hormone analogues prior to embolization. In these circumstances, insufficient volumes of embolization particles delivered to the fibroids may cause incomplete infarction. Failure to completely devascularize the fibroids can affect long-term clinical response and may lead to high recurrence rates even if, surprisingly, some of these women may have initial relief of symptoms. "The quality of the initial embolization greatly influences clinical outcome," says Pelage.

Prevention of recurrence

Key to a successful devascularization of the fibroids is the prevention of arterial spasm. This is done with the systematic use of microcatheters, the dilution of embolization particles, a slow rate of injection and delaying post-embolization angiograms to identify secondary redistribution of embolized arteries. Although different embolizing agents can be utilized, all angiographically identified fibroid branches should be occluded.

Mid-term recurrence also occurs in women who receive only unilateral arterial embolization or have an additional arterial supply to their fibroids from sources such as the ovarian arteries. Initial clinical improvement and fibroid shrinkage may be observed at six months but there is the risk of possible recurrence if part of the fibroid is not infarcted. Pelage reports that accurate identification of ovarian artery supply to the fibroids seems particularly helpful in women with previous surgery or tubo-adnexal disorder or in those presenting with large fundal fibroids.

Appropriate post-procedure imaging is the key to early detection of uninfarcted uterine fibroids. In order to understand or predict symptom recurrence, Pelage prefers to employ contrast-enhanced MRI to standard T1 and T2 weighted images, as it is more accurate in detecting the percentage of tissue perfused in each fibroid. "It has been demonstrated that women with persistent fibroid perfusion after embolization are at higher risk of clinical recurrence after two to three years," reports Pelage. "Systematic and early detection of residual fibroid vascularization is now part of our usual clinical practice. In our experience and those of others, complete fibroid devascularization of all identified fibroids can be obtained in 75-85% of cases. To date, we have not seen any cases of symptom recurrence in women with complete fibroid infarction. But all women with incomplete infarction seem to come back for symptom recurrence frequently observed more than two years after embolization."

Although totally new fibroids may grow (true recurrence) in a woman post UFE, Pelage's team has yet to report any successfully infarcted fibroid that was to have recurrent growth after embolization. Pelage warns that to simply use volume reduction as an indicator of the clinical success of UFE is misleading. Although incomplete fibroid infarction may not affect immediate outcome, there is strong evidence that regrowth of uninfarcted fibroid tissue may result in symptom recurrence after several years. "The clinical credibility of interventional radiologists against hostile gynecologists is directly related to their ability to predict and manage clinical recurrences," concludes Pelage.