Trends in incidence and survival outcome of epithelial ovarian cancer: 30-year national population-based registry in Taiwan

OBJECTIVE To investigate the changes of incidence and prognosis of epithelial ovarian cancer in thirty years in Taiwan. METHODS The databases of women with epithelial ovarian cancer during the period from 1979 to 2008 were retrieved from the National Cancer Registration System of Taiwan. The incidence and prognosis of these patients were analyzed. RESULTS Totally 9,491 patients were included in the study. The age-adjusted incidences of epithelial ovarian cancer were 1.01, 1.37, 2.37, 3.24, 4.18, and 6.33 per 100,000 person-years, respectively, in every 5-year period from 1979 to 2008. The age-specific incidence rates increased especially in serous, endometrioid and clear cell carcinoma, and the age of diagnosis decreased from sixty to fifty years old in the three decades. Patients with mucinous, endometrioid, or clear cell carcinoma had better long-term survival than patients with serous carcinoma (log rank test, p<0.001). Patients with undifferentiated carcinoma or carcinosarcoma had poorer survival than those with serous carcinoma (log rank test, p<0.001). The mortality risk of age at diagnosis of 30-39 was significantly higher than that of age of 70 years or more (test for trend, p<0.001). The mortality risk decreased from the period of 1996-1999 (hazard ratio [HR], 0.90; p=0.054) to the period after 2000 (HR, 0.74; p<0.001) as compared with that from the period of 1991-1995. CONCLUSION An increasing incidence and decreasing age of diagnosis in epithelial ovarian cancer patients were noted. Histological type, age of diagnosis, and treatment period were important prognostic factors for epithelial ovarian carcinoma.