Reliability of the routine cytological diagnosis in bladder cancer

Objectives: To establish the reliability of three cytopathologists for cyto logical diagnosis of primary bladder tumors. Methods: Preoperative voided u rine specimens of 71 patients with bladder cancer and 55 noncancer controls were retrospectively and blindly reviewed by 3 independent cytologists, an d their results compared. The estimation of the interobserver agreement was calculated using the weighted kappa coefficient, A multivariate analysis w as carried out to identify the factors associated with the disagreement bet ween the three observers. The sensitivity and specificity for each of the p articipants was calculated in order to clearly identify the origin of the d isagreement, in terms of the performance of the diagnostic test in the hand s of each observer. A comparison of the overall diagnostic performance was made by plotting sensitivity versus 1-specificity. Results: The weighted ka ppa coefficient among the 3 observers was 0.46. The multivariate analysis d id not identify any variable that could have caused such disagreement. Vast differences in sensitivity and specificity were detected between observer 1 (sens, 0.90, spec, 0.45) and observers 2 (sens. 0.67, spec. 0.72) and 3 ( sens. 0.71, spec. 0.80), but the overall diagnostic performance (sensitivit y vs. 1-specificity) was superimposable in the 3 cases (p = NS). Conclusion s: Simple, reproducible and agreed-on-diagnostic criteria should be establi shed to yield reliable results in a group of cytologists, The consideration of individual diagnostic performances can give a false idea of homogeneity between observers. In this field, concordance analysis makes quality contr ol reliable and should be a routine procedure of any pathology department.