The diagnostic value of the ThinPrep pap test in endometrial carcinoma: a prospective study with histological follow-up.

Case-control studies have demonstrated that the ThinPrep Pap test may provide improved detection of endometrial carcinoma. The purpose of this study is to prospectively examine the diagnostic potential of the ThinPrep Pap test in the detection of endometrial carcinoma. ThinPrep Pap test slides were collected from high-risk patient groups. Pap-stained slides were reviewed and the cytological diagnosis was rendered independently by investigators. Each case was assigned to one of the four diagnostic categories: within normal limit (WNL); atypical glandular cells (AGC); atypical endometrial cells (AEC); or adenocarcinoma, probably endometrial origin. After cytological diagnosis was made, the histological follow-up diagnosis was obtained through the laboratory information system and the cyto-histological correlation was analyzed. Of 106 patients identified, 60 had histological follow-up. For all eight cases interpreted by cytology as positive, endometrial carcinoma was confirmed histologically. Among 25 patients with normal endometrial cells present, histological follow-up showed benign endometrium. Among 17 cases interpreted cytologically as AEC, 14 cases (82.4%) had benign histological follow-up and 3 cases (17.6%) had endometrial carcinoma. All 11 cases (100%) classified as AGC had benign histological follow-up. The sensitivity and specificity of detecting endometrial malignancy were 72.7% and 100%, respectively. The positive predictive value was 100%. In this prospective study, we demonstrated that the Thin Prep Pap test had a reasonably high sensitivity and/or specificity in detecting endometrial carcinoma.