Prevalence of cysts in epithelial ovarian cancer

Ovarian carcinomas mostly appear as large cystic masses. However, the exact prevalence of cysts in epithelial ovarian cancer (EOC) has never been documented as well as the tumor factors that are related to the presence of cysts. Demonstrating the prevalence of cysts in EOC is essential for research focused on predictive and prognostic biomarkers in ovarian cyst fluid.

From 233 patients with primary EOC who underwent surgery, pathological data were collected from pathology reports. Univariate and multivariate logistic regression were used to analyze the relationship between the presence of cysts and other tumor characteristics.

Cysts in EOC were present in 83.7% of the patients and were mostly (61%) multilocular. The most common histological subtypes (serous, mucinous, endometrioid, clear cell) contained cysts in more than 85% of the cases. In univariate regression analysis, early FIGO stage, low tumor grade and a large tumor size were significantly associated with the presence of cysts (OR (95% CI)=5.312 (1.81-15.57), 6.906 (2.31-20.66) and 1.169 (1.08-1.27), respectively). In multivariate regression analysis, apart from tumor size, only tumor grade was independently associated with the presence of cysts (adjusted OR (95% CI)=4.234 (1.36-13.22)).

The large majority of all EOCs contained cysts. Histological subtype, FIGO stage, tumor necrosis and age were not associated with the presence of cystic EOC. In contrast, tumor grade and tumor size were independently related to the presence of cystic EOC. This means that cystic EOCs represent a subgroup of larger and more well-differentiated tumors. The evident relationship between the presence of cysts and differentiation grade is interesting from a clinical point of view as grading is especially important for the prognosis and treatment of patients with stage I EOC.