Risk factors for recurrence of endometrioid ovarian cysts after combined treatment

BACKGROUND: The main method of endometrioid ovarian cyst treatment is considered surgery with further hormone therapy. However, the recurrence rate of endometriomas, even 57 years after combined treatment, can reach 50%. 
AIM: The aim of this study was to identify risk factors for recurrence of endometrioid ovarian cysts among women of reproductive age after combined treatment. 
MATERIALS AND METHODS: This study included 196 women operated on for ovarian endometriosis. We carried out a comparative analysis of the data between the study groups: the main group comprised 45 patients with a relapse of the disease; the comparison group consisted of 151 women without a relapse. Hematoxylin-eosin staining was used for morphological examination of the surgical material, and monoclonal mouse antibodies to Ki-67 and bcl-2 (DAKO, Denmark) were used for immunohistochemical examination. The construction of a statistical model for predicting the recurrence of ovarian endometriosis among women of reproductive age was carried out using multivariate binary logistic regression analysis in reverse stepwise mode. The influence of the independent variable on the likelihood of recurrence was determined using the odds ratio and its 95% confidence interval, with the sensitivity, specificity and diagnostic accuracy evaluated. 
RESULTS: A set of predictors has been identified that provides the greatest contribution to recurrence of ovarian endometriosis. Immunohistochemistry study showed that the level of Ki-67 protein was higher in the group with relapsed endometriomas compared to the non-recurrent course: in the epithelial lining of the cyst, 9.08 2.60 and 2.06 1.16%, respectively (p = 0.043); in the cytogenic stroma, 11.67 4.10 and 9.81 3.40%, respectively (p = 0.48). Bcl-2 expression was reduced in the epithelial lining of the cyst capsule in the main group in comparison with the material where there was no recurrence: 0.653 0.043 and 0.961 0.056%, respectively (p = 0.31). 
CONCLUSIONS: Of significance in predicting the risk of recurrence of ovarian endometriosis is a combination of four signs in one patient: primary infertility; pelvic organ surgery in history, unrelated to endometriosis; elevated levels of CA-125 oncoprotein and proliferative changes in cytogenic stroma cells, as well as increased expression of the Ki-67 antigen in the epithelial lining of the endometrioid cyst.