Endometriosis Linked to Ovarian Cancer, but Absolute Risk Stays Low

Endometriosis, particularly ovarian endometrioma, is associated with an increased risk of ovarian cancer, according to a new review. The strongest link was seen with clear cell and endometrioid ovarian cancers.

Despite this, the review emphasizes the absolute lifetime risk remains low at 1.9%. This distinction is clinically important, as relative risk estimates may appear substantial while translating into a low absolute probability for most patients.

The review highlights shared mutations in ARID1A, PIK3CA, and KRAS, supporting a biological pathway from endometriosis to malignancy. The ovarian microenvironment, with high free iron and local estrogen metabolism, may promote DNA damage.

Long-term oral contraceptive use offers significant protection against ovarian cancer in women with endometriosis, with benefits lasting over a decade after stopping. Surgical excision of ovarian endometriomas may reduce risk, but must be weighed against fertility goals. Routine prophylactic salpingo-oophorectomy is not recommended for endometriosis alone.