Study population: To evaluate the epidemiology and prognosis of ovarian cancer in Taiwan, we will conduct a nationwide analysis through linking national cancer registry database. Every citizen in Taiwan has a life-long identification number to link individual information, including health status. The Taiwan household registry database provided by Department of Health will be the source population. National household registry and death certificate will be adopted to ascertain the live status of study subjects, and provided individual demographic characteristics.All individual linkages between databases will be conducted according to the study protocols, i.e. databases will be linked by corresponding identification number, name (Chinese characters) and birthday, and all data included in this study will be analyzed without individual identification information. The agreement of utilizing the databases in the study was obtained from the Bureau of Health Promotion in Taiwan.