Incident and death cases ascertainment: Patients with ovarian cancer, including epithelial ovarian carcinoma, germ cell tumors, sex cord tumors … etc., will be identified from computerized linkage to the Taiwan national cancer registry with International Classification of Diseases for Oncology Third Edition T-code C569. Histological types will be identified from morphology code in the cancer registry database. Women affected by ovarian cancer and found death due to ovarian cancer (International Classification of Diseases 9th edition code 183) in deaths certificate will be defined as death cases.