Predictors of resolution of complex atypical hyperplasia or grade 1 endometrial adenocarcinoma in premenopausal women treated with progestin therapy

Objective. To To identify clinical and pathologic predictors of response to progestin treatment in premenopausal women with complex atypical hyperplasia (CAH) and Grade 1 endometrial adenocarcinoma (Grade 1 EA). Methods. Forty premenopausal patients with Grade 1 EA or CAH who underwent progestin therapy for a minimum of 8 weeks were retrospectively identified. Patient characteristics and histopathologic features of pretreatment and first follow-up endometrial specimens were evaluated as predictors of resolution, defined as absence of hyperplasia or carcinoma. Results. Kaplan-Meier analysis indicated 63% resolution at 18 months of follow-up. Multivariate classification analysis showed that resolution rates were higher in individuals with a low pre-treatment qualitative abnormal architecture score and a BMI <35 (Standardized Resolution Ratio (SRR) = 1.48, p=0.03). The diagnosis of benign endometrium or simple hyperplasia on the first follow-up specimen was highly predictive of resolution (SRR=2.25, p=0.002). Resolution rates were lower among subjects with a high pre-treatment qualitative abnormal architecture score (SRR=0.37, p<0.03) and lowest in subjects whose first follow-up specimen showed persistent complexity, atypia, or carcinoma with adjacent stromal decidualization (SRR=0.24, p=0.002). Conclusions. Clinical and pathologic parameters can predict response to progestin therapy in premenopausal women with CAH and Grade 1 EA. A low likelihood of resolution is predicted by an unfavorable pre-treatment architectural score and lack of pathological response in the first specimen, despite adjacent stromal decidualization. (C) 2011 Published by Elsevier Inc.