Cancer Implications for Patients with Endometriosis

Endometriosis is defined as the presence of viable endometrial glands and stroma outside of the uterus. It is a common disease, occurring in 5 to 15% of all women. Endometriosis is associated with chronic pelvic pain and infertility and often requires surgical intervention for definitive treatment. Although it is a benign gynecologic condition, endometriosis shares pathophysiologic features with cancer. In recent years, both histologic and epidemiologic evidence has accumulated, suggesting that ovarian endometriosis may give rise to malignant ovarian tumors, primarily those that are epithelial in origin, known as endometriosis-associated ovarian carcinoma (EAOC) including ovarian clear cell carcinoma, endometrioid carcinoma, and the least common, seromucinous tumors. Women with endometriosis have a two- to threefold increase in absolute risk of developing epithelial ovarian cancer, especially clear cell and endometrioid subtypes. Somatic mutations, such as ARID1A, PIK3CA, and PTEN, may promote the progression of benign endometriosis to carcinoma. Endometriosis has been implicated in the development of other malignancies, including endometrial and breast cancer. In this review, we critically appraise the data regarding the association between endometriosis and ovarian cancer and the potential correlation of endometriosis with other cancers.