Demographic Clinical and Prognostic Factors of Primary Ovarian Adenocarcinomas of Serous and Clear Cell Histology-A Comparative Study.

To compare clinical demographic and prognostic factors as well as overall survival in a nationwide cohort of patients diagnosed with ovarian clear cell carcinoma (oCCC) and high grade ovarian serous adenocarcinoma (oSAC) during 2005 to 2013.Population-based prospectively collected data on oCCC (n = 179) and oSAC (n = 2363) cases were obtained from the Danish Gynecological Cancer Database. χ, Fischer or Wilcoxon-Mann-Whitney, multivariate logistic regression, univariate Kaplan-Meier, and multivariate Cox regression tests were used. Statistical tests were 2-sided. P values less than 0.05 were considered statistically significant.The oCCC cases were significantly younger than oSAC cases. An inverse association between ever smoking and oCCC as compared to oSAC was observed and a significantly higher proportion of oCCC was found to be nulliparous (odds ratio, 0.62; 95% confidence interval, 0.37-0.92).Although more oSAC than oCCC cases diagnosed in stage III or IV were referred to neoadjuvant chemotherapy, a higher proportion of oCCC achieved complete cytoreduction at primary debulking surgery and/or had lymphadenectomy performed; overall survival were poorer among oCCC than oSAC cases in analyses restricted to stages III and IV (odds ratio, 1.87; 95% confidence interval, 1.35-2.61), whereas no difference between early stage oCCC and oSAC was observed.The study confirms that demographic features and risk factors differ between oCCC and oSAC cases. Furthermore, our findings confirm that advanced stages of oCCC have a poorer prognosis compared with oSAC probably because of the resistance toward adjuvant chemotherapy. The observed differences highlight the need for subtype-specific research and individualized treatment within ovarian cancer.