BACKGROUND

Uterine fibroids are the most common benign uterine tumours present in women of reproductive age. Mifepristone (RU-486) competitively binds and inhibits progesterone 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 METHODS

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, I(2) = 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; I(2) = 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.

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.