6th ESACP Congress, Heidelberg, April 7-11, 1999

A107
COMPARISON OF DIAGNOSTIC EFFICIENCY OF DNA-FLOW- AND -IMAGE- CYTOMETRY IN 200 EFFUSIONS OF TEN SEROUS CAVITIES
Motherby H, Kube M, Pomjanski N, Boros A, Knops K, Böcking A

Institute of Cytopathology, Heinrich-Heine-University Düsseldorf, Germany

Aims: To compare 1. the diagnostic usefulness of DNA-flow- (FCM) and -image-cytometry (ICM) for the identification of malignant cells in effusions and 2. sensitivities of different algorithms to identify DNA-aneuploidy. Material and Methods: 200 effusions of which 80 contained cytologically unequivocal tumor cells (74 carcinoses, 6 mesothelio- mas), 46 with equivocal cytological diagnoses suspicious for tumor cells, and 74 without tumor cells. Clinical follow-up was available for all patients. Effusions were formalin fixed, protease disaggregated DAPI stained for FCM and performed with a PAS cytometer (PARTEC, Münster, Germany). Image-cytometry was performed on air-dried smears after Feulgen staining with the AutoCyte QUIC DNA workstation (AutoCyte, Burlington, USA). Results: The application of three different algorithms each in FCM and ICM increased the rate of aneuploidy detection in both procedures. DNA-aneuploidy was detected in 58.8 % of tumor cell positive effusions by FCM and in 87.5 % by ICM (prevalence), but never in tumor cell negative samples or in effusions without malignant tumors in the follow-up. 19.6 % of equivocal effusions in FCM and 45.7 % in ICM revealed DNA-aneuploidy. The positive predictive value of DNA-aneuploidy for tumor cells in cytologically equivocal effusions was 100.0 % for both FCM and ICM. The negative values were 48.6 % and 72.0 % respectively. Whereas FCM could differentiate peaks differing only 4 % in DNA content ICM could identify single nuclei with abnormally high DNA-values (9c EE). Discussion: The lower detection rate of DNA-aneuploidy of FCM compared with ICM was due to frequent prevalence of lymphocytes and granulocytes over mesothelial- and tumor cells. This disadvantage can be overcome by differential centrifugation or immunocytochemical gating in multiparameter flow-cytometry.