Mifepristone for uterine fibroids

Uterine fibroids are also known as uterine leiomyoma,myoma or  fibromyoma and are non-cancerous benign growths in the uterus. Fibroids are the most common benign tumours in females and are typically found during the middle and later reproductive years. Common symptoms include heavy bleeding, menstrual pain, pressure in lower abdomen, infertility or miscarriage. Fibroids can be treated with surgery using either myomectomy (removal of fibroids leaving the uterus in place) or hysterectomy (removal of uterus). Drugs such as mifepristone have been suggested as a therapeutic option. This review includes three trials and 112 women with uterine fibroids under mifepristone treatment. These clinical trials included a small number of participants and show limited methodological quality. The studies included in this review show that mifepristone had a moderate effect in relief of bleeding and showed an improvement in fibroid-specific quality of life. Determination of the effects of mifepristone on uterine fibroid volume requires much larger trials to draw a confident conclusion for mifepristone in clinical use.

Authors' conclusions: 

Mifepristone reduced heavy menstrual bleeding and improved fibroid-specific quality of life. However, it was not found to reduce fibroid volume. Further well-designed, adequately powered RCTs are needed before a recommendation can be made on the use of mifepristone for the treatment of uterine fibroids.

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Background: 

Uterine fibroids are the most common benign uterine tumours present in women of reproductive age. Mifepristone (RU-486) competitively binds and inhibitsprogesterone receptors. Studies have suggested that fibroid growth depends on the sexual steroids. Mifepristone has been shown to decrease fibroid size. This review summarises the effects of mifepristone treatment on fibroids and the associated adverse effects as described in randomised controlled trials.

Objectives: 

To determine the efficacy and safety of mifepristone for the management of uterine fibroids in pre-menopausal women.

Search strategy: 

We searched the specialised register of the Cochrane Menstrual Disorders and Subfertility (Cochrane Menstrual Disorders and subfertility Review Group), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4), MEDLINE, EMBASE, PsycINFO, and CINAHL (to November 2011). We handsearched a number of journals, and searched reference lists, databases of ongoing trials and the Internet. There were no language restrictions.

Selection criteria: 

Only truly randomised controlled trials of mifepristone versus other forms of medical therapy or placebo in pre-menopausal women with confirmed uterine fibroids were included.

Data collection and analysis: 

Four authors independently extracted data and assessed trial quality. Data were analysed using the Peto odds ratios (OR) for dichotomous data and the weighted mean differences for continuous data, with 95% confidence intervals (CI). Meta-analyses were performed using the fixed-effect model.

Main results: 

Three studies involving 112 participants were included. Comparison interventions included different dosages of mifepristone, placebo and vitamin B tablets. There is evidence that treatment with mifepristone relieves heavy menstrual bleeding compared with placebo (Peto OR 17.84; 95% CI 6.72 to 47.38; 2 RCTs, 77 women, I2 = 0%). Three studies (Bagaria 2009; Engman 2009; Fiscella 2006) were included in the meta-analysis of this comparison. There was no evidence of an effect of mifepristone on the fibroid volume (standardised mean difference (SMD) -0.02; 95% CI -0.38 to 0.41; 99 women). Two studies (Bagaria 2009; Fiscella 2006) were included in the meta-analysis of this comparison. There was no evidence of an effect of mifepristone on uterine volume (mean difference (MD) -77.24; 95% CI -240.62 to 86.14; 72 women). The pooled data suggest an increased adverse event (abnormal endometrial histology) in the mifepristone group compared to placebo (OR 31.65; 95% CI 4.83 to 207.35; 2 RCTs; 54 women; I2 = 0%). Only one study (Bagaria 2009) reported endometrial hyperplasia at the end of the therapy (12/19 women in the mifepristone group versus 0/16 in the placebo group; OR 55.0; 95% CI 2.86 to 105.67). Engman 2009 found a significantly higher rate of cystic glandular dilatation in women in the mifepristone group (5/8 women biopsied) compared with the placebo group (1/11 women biopsied) (OR 16.67; 95% CI 1.36 to 204.03). One study (Fiscella 2006) suggested significant improvements (P < 0.001) for specific quality of life outcomes.

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