OBJECTIVE: 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.
OBJECTIVE: 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.