Cancer is the leading cause of mortality in the investigators country. According to the statistics of the Department of Health, the incidence of ovarian cancer increased in recent years and the mortality rate is highest in all gynecologic malignancies in Taiwan. Ovarian cancer becomes a more and more important disease gradually in the field of gynecologic malignancies. The classification of histology in ovarian cancer included epithelial ovarian cancer、germ cell tumors、sex-cord cell tumors…etc. Epithelial ovarian carcinoma is the most common ovarian cancer clinically. Early diagnosis is difficult due to the lack of obvious initial symptoms, so ovarian cancer patients are usually at advanced stage when the diagnosis is confirmed. The prognostic parameters for ovarian carcinomas include tumor stage, histological subtype, degree of malignancy, residual tumor after surgical intervention and the response to chemotherapy. However, the possible etiology and mechanism of ovarian cancer is still unclear. However, there is no epidemiologic data of ovarian cancer in Taiwan. Therefore the investigators propose this study to use Taiwan registry database provided by Department of Health to analyze the epidemiology and prognosis of ovarian cancer patients in Taiwan.