LAUSR

Abstract In this study, the risk factors for ovarian endometriosis (OE) malignancy and its recurrence were explored in Chinese women. For OE malignancy occurrence, the age of marriage, abortion times, course of OE, body mass index (BMI), other benign uterine complications, and shorter parturition times were identified as risk factors using univariate analyses. Among them, age at marriage, course of OE, BMI, and decreased parturition times were identified as risk factors using multivariate analyses. For OE malignancy recurrence, the risk factors included clinical staging, histological classification, and chemotherapy by univariate analysis; and clinical stage, clear-cell carcinoma, and fewer chemotherapy cycles by multivariate analyses. In summary, we concluded that higher ages at marriage, longer courses of ovarian endometriosis, shorter parturition times, and additional benign uterine complications may increase the risk of OE malignancy. Advanced clinical stages, clear-cell carcinomas, and fewer chemotherapy cycles may promote OE malignancy recurrence. Impact statement What is already known on this subject? Endometriosis is one of the most common gynaecological diseases. Although endometriosis is not a malignant disease, endometriosis cells have characteristics similar to cancer cells. The risk of malignant transformation rates of ovarian endometriosis is said to be 1:18. However, epidemiological evidence based on large population research in ovarian endometriosis malignancy is lacking. In addition, there were few studies focussing on the long-term prognosis of ovarian endometriosis malignancies. What do the results of this study add? This study revealed the possible occurrence and recurrence risk factors of ovarian endometriosis malignancy using univariate and multivariate statistics analyses. What are the implications of these findings for clinical practice and/or further research? A clinical retrospective study with a longer follow-up period is suggested for assessing the occurrence and recurrence risk factors for ovarian endometriosis malignancies.