Histologic subtypes and laterality of primary epithelial ovarian tumors

Objectives. To determine if the likelihood of bilateral primary ovarian tumors differs by histologic subtype. Methods. Using data collected by the Surveillance Epidemiology and End Results (SEER) program, the analysis included 22,328 women 25-84 years of age who were diagnosed with a borderline or malignant epithelial ovarian tumor during 1992-2000, categorized as to laterality and histologic subtype. Results. Malignant serous tumors were bilateral in 57.5% of cases. Corresponding figures for mucinous, clear cell, endometrioid and other epithelial tumors were 21.3%, 13.3%, 26.8%, and 35.6%, respectively. Borderline serous tumors were bilateral in 29.8% of the cases compared to only 7.0% of mucinous tumors. The tendency for serous tumors to present as bilateral was consistent across all categories of race, age, and stage. Conclusions. Serous tumors of the ovary are more commonly bilateral than ovarian tumors of other histologic subtypes. The reasons for this tendency remain to be determined. (c) 2004 Elsevier Inc. All rights reserved.