A Multicenter Study Comparing Mirena and Systemic Progestin for Endometrial Hyperplasia

Background:

Endometrial cancer is the most common gynecologic cancer in the Western world and the incidence is still increasing. Endometrial cancer is principally developing through preliminary stages called endometrial hyperplasia and 10-30 per cent will develop into carcinoma when left untreated. The incidence of endometrial cancer in Norway is presently about 650 cases per year and about 3000 cases of endometrial hyperplasia are estimated. Thus,correct and optimal treatment of endometrial hyperplasia will contribute to prevent endometrial cancer development and also in the long term, to reduce the incidence of endometrial cancer. Correct treatment of endometrial hyperplasia includes operative treatment with hysterectomy of the high risk cases and conservative treatment and follow up for patients with lower risk. As diagnostics of endometrial hyperplasia has been a challenge to pathologists, overtreatment of patients with low risk of cancer development is unfortunately still a problem. In the present study an objective scoring system, D-score, is used to classify the patients into low and high risk hyperplasia. D-score in an objective morphometric analysis and the scoring system has proved reliable to predict the prognosis of each single case as to cancer development or not. By tradition low risk endometrial hyperplasia is treated conservatively with progestin hormones, however, no national routines really exist according to dose, type of progestin, treatment time or distribution route, however, varying doses of per oral treatment is mostly used.

Progestins hormones are known to have a growth regulatory effect on the uterine mucosa. However, treatment success after per oral therapy has shown that up to 50% are non-responders after per oral treatment. On the other hand a few recent studies have reported successful results after using the LNG-IUD as treatment for endometrial hyperplasia with 100 per cent treatment response.

The levonorgestrel impregnated impregnated intrauterine originally constructed for menorrhagia and contraceptive use, is delivering more than hundred times increased concentration of progesterone to the uterine mucosa compared to per oral therapy. Thus , the favourable treatment is attributable to the increased concentration of progestins obtained in the uterine mucosa. Another advantage is that treatment can last for years and that side-effects seen for per oral treatment after progestin therapy can be avoided.

Inclusion: