Validation of the ThinPrep papanicolaou test for cervical cancer diagnosis

Objectives. Although the accuracy of the Thin-Prep Papanicolaou (Pap) Test has been demonstrated in the detection of precursor lesions to cervical cancer, its performance in identifying invasive cancer has not been adequately evaluated. These studies were designed to determine the effectiveness of the ThinPrep method in diagnosing invasive cervical cancer. Materials and Methods. In four clinical studies, 47 cases of cervical cancer were processed by both conventional and ThinPrep techniques, and the cytological diagnoses and detection rates were compared. Additional studies evaluated the potential of cell loss during the ThinPrep filtration process. Results. A diagnosis of cancer was made in 45 cases (95.7%) by the ThinPrep method and in 44 cases by conventional Pap smear (93.6%). In the two cases not diagnosed by the ThinPrep method, one was diagnosed as atypical squamous cells of undetermined significance and one as atypical glandular cells of undetermined significance. In the conventional smears, one of the three cases not identified as cancer was atypical squamous cells of undetermined significance, and the other two cases were unsatisfactory. In addition, the ability of the ThinPrep method to demonstrate tumor diathesis and to retain diagnostic cells by the filtration process was confirmed. Conclusions. These studies indicate that the ThinPrep method is at least equivalent to the conventional Pap smear method for the demonstration of squarnous cell carcinoma, adenocarcinoma, and other cervical malignancies.