Breast Cancer Risk Factors in Patients With Endometriosis

Background: Endometriosis is a common chronic inflammatory, estrogendependentdisease with characteristics similar to cancer. Epidemiological studies ofthe association between endometriosis and breast cancer have yielded inconsistentresults. The present study aimed to investigate the association betweenendometriosis and breast cancer risk factors. Methods: This case-control study (with ۲۲۲ persons in each group) wasconducted in Arash Women's Hospital from ۲۰۱۴ to ۲۰۱۷. Women withlaparoscopically proven endometriosis were considered as cases. Controls wereselected from women who had previous laparoscopic surgery due to any reason, andthe absence of endometriosis was confirmed in them. Results: Multivariate logistic regression analysis by considering the risk factors(age, body mass index, gravidity, age at first pregnancy, age at menarche, history ofbreast-feeding, history of oral contraceptive and hormone use, history ofmiscarriage and induced abortion, breast cancer in first-degree relatives, andphysical activity) revealed that endometriosis was positively association with age atfirst pregnancy (OR = ۱.۱۶, ۹۵% CI: ۱.۰۸-۱.۲۵; P < ۰.۰۰۱), history of oralcontraceptive use (OR = ۳.۹۱, ۹۵% CI: ۱.۹۲-۷.۹۵; P <۰.۰۰۱), and history ofhormone use (OR = ۵.۸۲, ۹۵% CI: ۲.۷۰-۱۲.۵۶; P <۰.۰۰۱), and negatively associatedwith gravidity (OR = ۰.۶۱, ۹۵% CI: ۰.۴۲-۰.۹۱; P = ۰.۰۱), and history of breastfeeding(OR = ۰.۳۷, ۹۵% CI: ۰.۱۶-۰.۸۶; P = ۰.۰۲).Conclusion: Women with endometriosis have some of the breast cancer riskfactors in their history, and these risk factors (gravidity, age at first pregnancy,history of breast-feeding, and OCP or hormone use) can change the risk ofendometriosis as they increase or decrease the risk of breast cancer.