Epithelial Ovarian Cancer with Endometriosis is not Associated with Menopausal Status: a Co-Association Study at Prapokklao Hospital

Objective: To determine any association between the menopausal status and epithelial ovarian cancer coexisting with endometriosis (EOC-E). In addition, the prevalence and possible risk factors were assessed. Methods: Medical records of 172 women with epithelial ovarian cancer between January 2011 and December 2016 at Prapokklao Hospital were reviewed and divided into two groups: EOC-E defined as the case group and without endometriosis (EOC-NE) as the control group. Results: The proportion of EOC-E was 18% (31/172). There were no significant differences between the two groups in baseline clinical characteristics and presenting symptoms except for history of smoking and abnormal uterine bleeding found more often in EOC-E cases. Most EOC-E were of clear cell histological type followed by endometrioid and serous types (35.5, 25.8 and 22.6 %; respectively). The clear cell type was 8 times more likely in the EOC-E than in the EOC-NE (OR 8.0, 95% CI 2.97-21.89, p-value <0.001) group. Nulliparity and smoking increased risk of EOC-E 2 and 7 times, respectively (OR 2.3, 95%CI 1.03-5.00, p-value 0.041 and OR 7.4, 95%CI 1.18-46.63, p-value 0.032). Conclusions: EOC-E are relatively common. Abnormal uterine bleeding is the only significant presenting symptom in the EOC-E as compared with the EOC-NE group. Endometriosis was a predictive factor for clear cell and endometrioid type I EOC. Menopausal status and age were not associated with a presentation of endometriosis with EOC