Ploidy assessment of benign and malignant ovarian tumors by flow cytometry. A clinicopathologic study.

In a prospective study, 112 fresh ovarian tumor samples were collected from 83 consecutive patients. Cellular DNA content was measured by flow cytometry. All the benign (n = 24) and semimalignant (n = 6) tumors were diploid. Of 50 malignant tumors, 24 (48%) were diploid and 26 (52%) were aneuploid. Aneuploidy was more frequent in the advanced stages of the disease, in tumors of low degree of differentiation, and in older patients. The patients with aneuploid tumors had smaller primary tumors and more often ascites. The fraction of cells with S-phase DNA content was higher in the aneuploid tumors. No association was seen to the tumor type. Ploidy determination is objective and reproducible. Aneuploidy associates to most negative prognostic factors in ovarian carcinoma and may reflect the aggressiveness of the tumor. The ploidy status may be taken into consideration in the stratification of patients of comparable risk for treatment studies.