Incidence and treatment outcomes of ovarian carcinosarcoma from the national cancer registry of Korea

Objective: To investigate the incidence and survival outcomes of ovarian carcinosarcoma in Korea between 1999 and 2018. Methods: Patients diagnosed with ovarian carcinosarcoma between 1999 and 2018 were identified from the Korea Central Cancer Registry (KCCR) and their information was collected. Age-standardized incidence rates (ASRs), annual percent changes (APC), and relative survival rates of ovarian carcinosarcoma were calculated and compared to those of epithelial ovarian cancer. Results: According to the KCCR, 458 cases of ovarian carcinosarcoma were detected, and accounted for 1.5% (458/30,679) of all epithelial ovarian cancers in Korea between 1999 and 2018. The ASR of ovarian carcinosarcoma between 1999 and 2018 was 0.064 per 100,000 women. The incidence rate of ovarian carcinosarcoma increased during the study period, with an ASR of 0.029 per 100,000 in 1999 and 0.073 per 100,000 in 2018. The APC of ovarian carcinosarcoma during 1999-2018 was 5.86 (p<0.001). The median overall survival (OS) of patients with ovarian carcinosarcoma was 39 months, and the 5-year OS rate was 42.5%. Among ovarian carcinosarcomas, patients with localized stages showed better clinical outcomes than those with regional or distant stages (5-year OS, 60.8%, 57.9%, and 32.8%, respectively; p<0.001). In addition, younger (<50 years) patients showed better OS than older (>= 50 years) patients (5-year OS, 52.6% vs. 40.2%; p<0.001). Conclusion: Our nationwide registry-based study demonstrated that the incidence of ovarian carcinosarcoma increased from 1999 to 2018 in Korea. Patients with advanced-stage disease and older age (>= 50 years) had poorer survival outcomes.