CERVICAL CYTOPATHOLOGY - AN EVALUATION OF ITS ACCURACY BASED ON CYTOHISTOLOGIC COMPARISON

Background. Although Papanicolaou cytology represents the most effecti ve technique to prevent and detect precancerous conditions of the uter ine cervix, its false-negative yield is still a reason of concern amon g pathologists and gynecologists. Methods. Because histologic control is one of the best ways to assess the accuracy of cytology diagnosis, the authors have investigated 1000 women who had cervical smears and t issue sampling obtained during the same colposcopic evaluation between 1987 and 1990. Results. Out of 1000 cases (average age, 34.6 years; r ange, 14-80 years), 918 had adequate, 62 had less than optimal, and 10 had unsatisfactory samples. Cytology unsatisfactory and less than opt imal cases as well as inadequate histology cases have been disregarded from all calculations. After histologic comparison, confirmed negativ es were 622 of 918 (67.8%). Cytologic diagnoses of cervical intra-epit helial neoplasia (CIN) I were 96, of CIN II were 44, of CIN III, inclu sive of carcinoma in situ, were 39, and of invasive carcinoma were 2. Atypical cases were 56. The overall sensitivity was 76.3%, with group sensitivity rates increasing directly with CIN grade. Positive predict ive value was 80.2%. Specificity was 93.0%, and negative predictive va lue was 91.3%. False-negatives were 59 of 681 (8.7%), basically due to sampling errors. Among true-positives, there was 1 category discrepan cy in 30 cases (mostly undercalled or overcalled CIN II) and 2 categor y discrepancies in 4 cases. Conclusions. Cervical cytology has an over all accuracy close to that reported in studies employing indirect cont rol methods, such as patient follow-up. Higher sensitivity rates emerg ed for CIN II, CIN III, and cervical carcinoma. Our figures of sensiti vity and specificity may represent a useful reference source for futur e studies dealing with quality control in cervical cytopathology.