Flow cytometry of peritoneal washings in gynecologic neoplasia

A prospective, double blind study was initiated to compare flow cytometry to cytopathology in detecting malignant cells within peritoneal washings. Deoxyribonucleic acid (DNA) histograms were generated using 4',6-diamidino-2-phenylindole (DAPI) as a DNA fluorochrome. Evaluation of these data revealed a correlation of 84.5% with the cytologic findings. Two specimens demonstrated euploidy in the presence of cytologically malignant cells (false negative), 28 of 128 specimens (21.8%) manifested aneuploidy with negative cytologic findings (false positive). Further evaluation of this latter subgroup revealed 22 of the 28 to possess unequivocal histologic evidence of malignancy, thus yielding an actual false positive rate of 4.7%. This preliminary study demonstrates that flow cytometry is a highly sensitive, accurate, and analytic method for the detection of malignant cells within peritoneal washings and that it may augment the cytologic examination. However, additional comparative studies are necessary to conclusively demonstrate its apparent diagnostic potential.