Do clear cell ovarian carcinomas have poorer prognosis compared to other epithelial cell types? A study of 1411 clear cell ovarian cancers

Objective. To compare the clinico-pathologic characteristics and survival of women with clear cell versus other epithelial ovarian cancers. Methods. Data were obtained from the Surveillance, Epidemiology and End Results Program between 1988 and 2001 and analyzed using Kaplan-Meier and Cox proportional hazards models. Results. Of 28,082 women with epithelial ovarian cancer, 1411 (5%) had clear cell, 13,835 (49.3%) papillary serous, 3655 (13%) endometrioid, 2711 (9.7%) mucinous, and 6470 (23%) had unspecified histologies. The median age of overall patients was 64 years; with clear cell patients presenting at younger age (55 years). The proportion of clear cell histology was significantly higher in Asians versus Whites, Blacks, and others (11.1% versus 4.8%, 3.1%, and 5.5%;p < 0.001). Clear cell carcinoma is more likely to be diagnosed at early-stage (67.3%) compared to 19.2% in serous, 61.6% endometrioid, and 61.3% in mucinous carcinomas (p < 0.005). Retroperitoneal lymph node metastases were found in 13.6% of serous carcinomas, 7.9% clear cell, 7.3% endometrioid, and 3.8% of mucinous (p < 0.001). Adjusted for stage, the 5-year disease-specific survival of patients with clear cell carcinoma is worse compared to serous: 85.3% vs. 86.4% for stage 1, 60.3% vs. 66.4% stage II, 31.5% vs. 35.0% stage III, and 17.5% vs. 22.2% for stage IV, respectively (p < 0.001). On multivariate analysis, age, stage, grade, histology, and surgical treatment were independent predictors of disease-specific survival. Conclusions. Our data suggest that women with clear cell ovarian cancer present at a younger age, are more likely to be Asian, and have a poorer prognosis compared to serous cancers. (c) 2008 Elsevier Inc. All rights reserved.