Morphometric differentiation between responsive tumor cells and mesothelial hyperplasia in second-look operations for ovarian cancer

We developed a procedure based on computerized image analysis to establish objective criteria for the differential diagnosis between mesothelial hyperplasia and cancer in peritoneal tissue samples obtained at second-look operations for ovarian cancer. The tumor tissue after chemotherapy was classified as "nonresponsive" if it was found by histologic criteria to be roughly similar to the tumor before chemotherapy and as "responsive" if it was found to be different (small clusters of bland-looking cells with no mitotic activity). Eighty-five samples of tissue had been classified previously by a pathologist into one of the four following groups: ovarian tumor prior to chemotherapy, "responsive" tumor, "nonresponsive" tumor, or mesothelial hyperplasia. Cell profiles of the tissue samples were studied by computerized image analysis using 21 morphometric descriptors derived from the manual tracings of tumor nuclei, including nuclear perimeter, nuclear area, maximal chord, circularity factor, and standard deviations of these descriptors. Size distribution curves of nuclear areas and maximal chords were included in the analysis. A multivariate discriminant analysis confirmed the separation into the four diagnostic groups, accomplished with consideration of the physical descriptors alone, except for some overlapping between groups 1 and 3. The separation between carcinoma and mesothelial hyperplasia was clear in all cases.