Normal endometrial cells in Papanicolaou smears: Prevalence in women with and without endometrial disease

Objective: To determine whether the prevalence of normal endometrial tells in Papanicolaou smears of women with and those without endometrial carcinoma or hyperplasia differs significantly. Methods: Papanicolaou smears of women with biopsy-proved endometrial hyperplasia or carcinoma diagnosed between 1990 and 1998 were reviewed for the presence of normal endometrial cells. Chi-square and a power analysis were used to compare these smears with results of smears from women older than 35 years of age with tissue diagnoses other than hyperplasia or carcinoma. All Papanicolaou smears obtained within the 5 years before endometrial sampling were reviewed. Each patient had at least one smear done within the previous 12 months. Clinical information was available for all patients. Results: Of the 201 women in whom endometrial hyperplasia (n = 103) or carcinoma (n = 98) was diagnosed, 4 (2%) had normal endometrial cells in otherwise negative Papanicolaou smears. Of the 289 women in the comparison group, 15 (5%) had normal endometrial cells in their Papanicolaou smears. The prevalence of normal endometrial cells did not differ significantly between the two groups (P =.071). The study had 80% power to detect a 5% or greater difference between groups. Conclusion: The prevalence of normal endometrial cells in Papanicolaou smears of women with endometrial carcinoma or hyperplasia does not significantly differ from that in women without these conditions. Reporting normal endometrial cells in Papanicolaou smears according to the recommendations of the Bethesda System may lead to unnecessary procedures and patient anxiety. (Obstet Gynecol 2000;96: 874-8.) (C) 2000 by The American College of Obstetricians and Gynecologists.).