Introduction/Background As we know, the risk of progression of endometrial hyperplasia to endometrial cancer is 5–28% over 20 years. Effective therapy for endometrial hyperplasia can be considered as a factor in the prevention of the development of endometrial cancer. The objective of this study was to evaluate the predictive potential of immunohistochemical (IHC) markers of the endometrium in assessing the effectiveness of therapy for endometrial hyperplasia without atypia (EH).

Methodology This prospective study enrolled 179 women aged 24 to 45 years with an abnormal uterine bleeding and diagnosed as having EH.Patients received progestins - in a cyclic mode from the 5th to the 25th day for 6 months. Endometrial samples for histological and IHC studies were taken at baseline and 3 months after the end of treatment. We assessed expression of estrogen receptors (ERα), progesterone receptors (PR-A, PR-B) and Ki67 separately in the glandular and stromal components of endometrium.

Results After 6 months of treatment, the efficacy of progestin therapy was 77.65%. A statistically significant difference was established in the expression level of the studied parameters between the groups of patients who responded to treatment and those who were resistant. Although each predictor alone lacked high prognostic value, a logistic regression equation combining the most significant predictors (ERα expression in the endometrial glands, PR-A, PR-B in the stroma and in the glands, Ki67 in the stroma) achieved 93% (AUC = 0.969 (95% CI: 0.938–1.000), sensitivity – 89.74%, specificity – 95.08%) correct predictions.

Conclusion This study presents difference in initial IHC profile of endometrium of patient who respond for progestin therapy and who was resistance. Our results indicate the potential benefits of using endometrial histological examination in combination with an IHC analysis of the endometrium in tailoring effective treatment strategies for endometrial hyperplasia. This would allow to effectively prevent development of f endometrial cancer.

Disclosures We have no financial relationships to disclose.