Evaluation of Endometrial Cytology: Cytohistological Correlations in 1,441 Cancer Patients

Background: Endometrial cytology by direct intrauterine sampling is the most common test for an initial evaluation of the endometrium in Japan. However, its diagnostic value for endometrial cancer remains unknown. Here, we assess the correlation between cytopathology and histopathology to evaluate the diagnostic value of cytology for endometrial cancer. Methods: Patients with histologically confirmed endometrial cancer and controls with a normal endometrium confirmed by hysterectomy had all undergone preoperative endometrial cytology between 2001 and 2010 at our eight institutions and were retrospectively analyzed. The cytological results were compared by clinical stage, histological type, differentiation, and sampling instrument. Results: We analyzed 1,441 endometrial cancer and 1,361 control cases. Endometrial cytology detected cancer in 1,279 (916 positive and 363 suspicious) cases with a sensitivity (positive plus suspicious cases) of 88.8% and a specificity of 98.5%. The positive rate was high in advanced-stage, nonendometrioid, and undifferentiated cases, but there was no significant difference in sensitivity between these clinical conditions. Conclusion: Endometrial cytology shows a relatively high sensitivity and specificity for endometrial cancer, and neither statistical measure is significantly affected by clinical stage, histological type, differentiation, sample numbers, or sampling instrument. These findings form a superior dataset for evaluating the efficacy of endometrial cytology. (C) 2014 S. Karger AG, Basel