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

A106
DNA-IMAGE-CYTOMETRY AND IMMUNOCYTOCHEMISTRY FOR IMPROVEMENT OF DIAGNOSTIC ACCURACY IN EFFUSION CYTOLOGY
Motherby H, Kube M, Friedrichs N, Pomjanski N, Buckstegge B, Knops K, Böcking A

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

Aims: 1. To identify the prevalence of immunohistochemical staining of 12 different epithelial antibodies and DNA-aneuploidy in tumor cell positive and negative effusions of the serous membranes. 2. To determine the positive and negative predictive values (PPV, NPV) of BerEP4 staining and DNA-aneuploidy detection in equivocal effusions for the occurrence of tumor cells. Material and Methods: 1. 87 effusions unequivocally containing carcinoma cells of different origins, 14 with malignant mesothelioma cells, and 53 without tumor cells were investigated, applying a panel of 12 different epithelial antibodies and DNA-image-cytometry. 2. 65 effusions with cytologically equivocal diagnoses suspicious for tumor cells were investi gated with the same techniques. Clinical and/or histological follow-ups were available for all patients. Results: BerEP4 evolved as the diagnostically most useful antibody. Its prevalence in effusions due to carcinoses was 95.4 %, 0 % in mesotheliomas and in reactive mesothelial cells. Its PPV for the occurrence of cancer cells in doubtful effusions was 100 %, its NPV 65.5 %. DNA-aneuploidy occurred in 95.4 % of carcinoses, in 57.1 % in mesotheliomas, and in 0 % in reactive effusions. Its PPV was 96.7 %, its NPV 72.0 % in doubtful effusions. By combination of both markers the PPV for malignancy increased to 97.7 %, the NPV for benignancy to 79.2 %. The differentiation between carcinoses and mesotheliomas was correct in all cases using both adjuvant methods. Discussion: The combined application of both adjuvant methods is able to reduce the rate of equivocal cytological diagnoses in effusions by about 8 % identifying cancer cells which cannot be diagnosed by morphology alone. Sensitivity of effusion cytology thus increases by about 8 %, specificity by about 6 % as could be shown in a third study on the impact of these adjuvant methods on diagnostic accuracy in a routine setting including 300 cases.