Endometrial cells as a predictor of uterine cancer

Background: With the recent cervix screening national guidelines recommending against reporting of benign endometrial cells, we examined South Australian data to see what impact this would have on detecting uterine cancers. Aims: To test whether benign endometrial cells detected in cervical cytology testing confer an increased risk of uterine cancer, and to ascertain what percentage of uterine cancers will be missed in cervical screening programs if these cells are not reported. Methods: The study was a retrospective cohort design of 1585 women with shed endometrial cells, each matched with three women without shed cells. All were linked with cancer registry data to check for uterine cancer diagnosis. Cox proportional hazards regression was used to check for any increase in cancer risk with shed endometrial cells. Using the calculated relative risks for uterine cancer diagnosis, we estimated the number of uterine cancers in South Australia associated with benign endometrial cells. Results: The presence of benign endometrial cells in a cervical cytology test increases the risk of uterine cancer sixfold. However, screening women with benign cells would involve a major increase in pathology work for only an 18% increase in uterine cancers detected. Conclusions: Until cytology systems have a higher sensitivity in detecting which benign endometrial cells are associated with uterine cancer, pathology laboratories are unlikely to be required to report these cells on tests. Inability to adjust for symptomatic status may have reduced the relevance of the results in this study.