Li J, et al. - The incidence of ovarian malignant involvement in young and premenopausal endometrioid endometrial cancer patients was ascertained and the possible risk factors were investigated. In young premenopausal patients with endometrioid endometrial cancer, the incidence of co-existing ovarian malignant neoplasms was low. The findings have implications for pre-operative counseling of patients and decision-making at the time of surgery.