Risk of Ovarian Cancer in Women with Endometriosis

Women who have endometriosis, especially ovarian cysts called endometriomas, face about twice the chance of developing ovarian cancer compared to those without the condition. The overall risk over a lifetime is still small, roughly 2 percent. Studies show that the same gene changes—ARID1A, PIK3CA, and KRAS—can appear in both endometriosis lesions and certain ovarian cancers. The environment inside an endometrioma may help these changes turn into cancer, but it is not a guarantee. Doctors use ultrasounds and MRI scans to spot endometriosis, yet these tools do not reliably detect when a cyst becomes cancerous. Blood tests for markers like CA‑125 and HE4 give extra clues, but they are not precise enough to replace imaging. Taking combined oral contraceptives (COCs) for many years lowers the risk of ovarian cancer in women with endometriosis.The protective effect can last more than ten years after stopping the pill, and it may also reduce risks of other cancers such as endometrial and colorectal. Surgery that removes ovarian cysts can also lower cancer risk, but it may lead to fewer eggs left in the ovaries and a chance that the cyst returns. This trade‑off is especially important for younger women who want to keep their fertility. For those with inherited cancer genes, removal of the ovaries and fallopian tubes is advised, but it is not a routine recommendation for all women with endometriosis. New research aims to create personalized risk calculators that combine genes, medical history, and lifestyle choices. Long‑term studies will tell whether keeping the cysts or removing them gives better outcomes for cancer prevention and survival. Managing endometriosis requires a team of specialists to balance cancer protection, fertility goals, and overall well‑being.