OBJECTIVE: To estimate cancer outcome and outcome predictors of women with endometrial intraepithelial neoplasia (EIN).
METHODS: Outcomes of women with first diagnosis of EIN (“index biopsy”) were determined by follow-up pathology. Patient characteristics were correlated with EIN regression, EIN persistence, and progression to cancer.
RESULTS: Fifteen percent (95% confidence interval [CI] 9.8–20.8%, 26 of 177) of index EIN biopsy samples had concurrent cancer. Of the women with cancer-free index EIN biopsy samples and follow-up by hysterectomy or more than 18 months of surveillance, 25% (95% CI 18.4–33.3%, 36 of 142) showed regression, 35% (95% CI 27.4–43.7%, 50 of 142) showed persistence, and 39% (95% CI 31.3–48.0%, 56 of 142) showed progression. Nonwhite ethnicity and progestin treatment reduced cancer outcomes (odds ratio [OR] 0.16, 95% CI 0.03–0.84 and OR 0.24, 95% CI 0.08–0.70, respectively), whereas body mass index greater than 25 increased malignant outcomes (body mass index 25 or higher, OR 3.05, 95% CI 1.10–8.45).
CONCLUSION: Endometrial intraepithelial neoplasia confers a high risk of cancer, but individual patient outcomes cannot be predicted. Management should include exclusion of concurrent carcinoma and consideration of hysterectomy.
LEVEL OF EVIDENCE: II