Image Analysis of Cellular DNA Content in Peritoneal Fluid of Patients with Ovarian Tumors of Low Malignant Potential and Invasive Epithelial Ovarian Cancer

Abstract

Image analysis has rarely been used to quantitate the DNA content of intact cells derived from peritoneal fluid in patients with ovarian malignancy. An average of 118 (range 100–208) of the most atypical, visually selected Feulgen-stained cells in peritoneal fluid obtained from 46 patients undergoing primary cytoreductive surgery for histologically proven ovarian tumors of low malignant potential and truly invasive ovarian cancer were evaluated retrospectively using the SAMBA-4000 Image analysis system. The patients were stratified into 3 groups: 16 with ovarian tumors of low malignant potential (LMP), 14 with low-stage disease (LSD) (FIGO I and II), and 16 with advanced-stage (ASD) (FIGO III and IV). A pattern of high-degree aneuploidy with negative balance (means: LMP, 3.3; LSD, 20.5; ASD, 32.0), increased proliferative index (LMP, 11.2; LSD, 16.1; ASD, 13.9), and percentage of cells with DNA content greater than 5C (LMP, 6.7; LSD, 6.5; ASD, 9.5) was demonstrated in the peritoneal fluid of 8 of 16 patients with LMP (50%), 8 of 14 patients with LSD (57%), and 13 of 16 with ASD (81%). The median disease-free interval for patients with invasive epithelial ovarian cancer with peritoneal DNA diploid tumor cells was 57 months and for those with DNA aneuploid tumor cells 28 months, while in patients with LMP it was 65 and 54 months, respectively. In total, 19 patients developed a recurrence (LMP, 2; LSD, 5; ASD, 12) of which 17 were shown to have DNA aneuploid cells in the peritoneal fluid. Multivariate analysis, however, did not identify aneuploid population in the fluid, ploidy balance, proliferation indices, or degree of hyperploidy as an independently significant variable for predicting recurrence. It did appear, however, that tumor cells in peritoneal fluid with a degree of hyperploidy greater than 8 had a strong correlation for development of recurrence, although not statistically significant. Interactive image analysis of tumor cells in peritoneal fluid proved to be a valuable adjunct to cytodiagnosis. Seven of 28 patients (25%) who were underdiagnosed by cytology alone (LMP, 2; LSD, 3; ASD, 2) were shown to have malignant cells in their peritoneal fluid, while 2 of 18 patients (11%) who were called positive by cytology (LMP, 1; LSD, 1) showed diploid pattern histograms and upon review were interpreted as reactive mesothelial cells.