Investigation of the 12-month efficacy and safety of low-dose mifepristone in the treatment of painful adenomyosis

Objective:To study the 12-month effects and possible mechanisms of low-dose mifepristone in the treatment of adenomyosis.Methods:Patients included in this retrospective study had painful adenomyosis and previously received 5 mg mifepristone daily(group A,n=45)or 5 mg mifepristone daily with a poor-effect levonorgestrel-releasing intrauterine device(group B,n=13)for 12 months.Uterine size,serum CA125 levels,estradiol levels,Visual Analogue Scale(VAS)score,endometrial thickness,and hemoglobin levels were compared before and after treatment and investigated again at 3 to 6 months after drug withdrawal.Another 8 patients with adenomyosis(group C,n=8)who underwent surgery for severe dysmenorrhea during the same period were only used as a control group for immunohistochemical research.Endometrial biopsy results and expression of nerve growth factor(NGF),cyclooxygenase-2(COX-2),and nuclear-associated antigen Ki-67(Ki-67)in endometrial tissues and adenomyotic lesions were also analyzed.Results:The VAS scores in both experimental groups at all time points during treatment and follow-up were significantly lower(P<0.001)than those before treatment.The uterine size was significantly reduced,and endometrial thickness was distinctly thicker after 12 months of treatment than that before treatment in group A receiving 5 mg/d mifepristone.The immunohistochemical expression of NGF and COX-2 decreased in both eutopic and ectopic endometrium after treatment,whereas that of Ki-67 slightly increased in eutopic endometrium after treatment and rapidly recovered to the baseline value after stopping mifepristone.There were no signs of hyperplasia,atypical hyperplasia,or malignancy in the endometrial biopsies.Conclusions:The results suggested that a daily dose of 5 mg mifepristone for 12 months down-regulated the expression of NGF and COX-2 and was effective in treating painful adenomyosis with few side effects.