Ploidy as a prognostic factor in ovarian cancer

Abstract

The cellular DNA content of 50 ovarian common epithelial carcinomas was determined by flow cytometry, and tumours were classified as being either diploid or aneuploid. A significant association between tumour stage and ploidy was demonstrated, with all diploid tumours being of an early stage (p less than 0.001). Forty percent of early-stage tumours (FIGO stages I and II) and all late-stage tumours (FIGO stages III and IV) were aneuploid. This heterogeneity with respect to DNA content among tumours of a similar stage may allow the identification of neoplasms with a different natural history. The proportion of S-phase cells determined by flow cytometry is a measure of cellular proliferation and may also be of prognostic significance. Diploid tumours had a median S phase of 9.8% (2.4-14.1%), while aneuploid tumours had a significantly higher S phase of 19.6% (7-24.7%; p less than 0.05). In this study there was no relationship between histological grading of invasive carcinomas and ploidy, but in view of the relatively small numbers and limited follow-up, it was not possible to perform a multivariate analysis of all known prognostic factors in ovarian cancer. Our results suggest that ploidy reflects tumour behaviour, but prolonged follow-up and increased patient accrual is necessary to assess whether the flow cytometric analysis of DNA content will provide clinically important information in ovarian cancer.