Comparison of conventional Papanicolaou smears and fluid-based, thin-layer cytology with colposcopic biopsy control in central Italy: a consecutive sampling study of 461 cases

The aim of this study was to compare the cytologic diagnosis and specimen adequacy of conventional Papanicolaou (CP) and fluid-based, thin-layer [ThinPrep (TP), Cytyc, Boxborough, MA] cervical cytology in a population from central Italy. CP and TP samples were collected simultaneously using a consecutive sampling method on women presenting for cervical screening. Colposcopy was performed as clinically indicated, and biopsy results were compared with cytologic diagnoses. Among the 461 patients included in the study, 413 were negative at both CP and TP, 9 had unsatisfactory results at both tests and 39 patients presented abnormal results at CP, TP or both. Cohen's Kappa was 0.77 showing good agreement between CP and TP test results. Histological data were available for 20 (51.28%) of the 39 patients with at least one positive test. Among the 13 patients with HSIL at histology, 7 had HSIL at CP (sensitivity 53.85%) and 5 at TP (sensitivity 38.46%). For all three patients with squamous cell carcinoma (SCC) at histology, CP and TP had shown the same diagnosis (sensitivity 100%). The positive predictive values were 33.33% for CP and 25.0% for TP regarding the LSIL diagnosis and 100% for both CP and TP regarding HSIL and SCC diagnoses. Our results may be influenced by the consecutive sampling procedure.