Exemestane in Treating Patients With Complex Atypical Hyperplasia of the Endometrium/Endometrial Intraepithelial Neoplasia or Low Grade Endometrial Cancer

Inclusion Criteria: * Females with a histologically proven CAH/ EIN or low grade (grade 1 or grade 2) endometrial carcinoma (EC) for which surgery is planned; the pathologic report from the referring facility will be used to determine pathologic eligibility; this report must be within 45 days of their baseline (pre-surgical) clinic visit * No prior treatment for CAH/EIN/EC * Post-menopausal confirmed with one the following criteria: * \>= 60 years of age * Age 56 to 59 years of age with \>= 2 years of amenorrhea * Age 56 to 59 years of age with \< 2 years of amenorrhea and follicle stimulating hormone (FSH) within institutional post-menopausal range. * Age 45 to 55 years of age with FSH within institutional post-menopausal range. The Ki-67 expression changes based on menopausal status and specifically varies based on what phase of the menstrual cycle the sample is collected. Therefore, in order to eliminate this source of variability, only postmenopausal women will be included in this trial. In addition, exemestane is currently approved for use in post-menopausal women only. * Eastern Cooperative Oncology Group (ECOG) performance status =\< 1 * Hemoglobin \>= 9 g/dL * Serum creatinine =\< 1.5 x upper limit of normal or calculated creatinine clearance \>= 60 mL/min using Cockcroft-Gault equation for patients with creatinine levels \> 1.5 x institutional upper limit of normal (ULN) * Total bilirubin =\< 1.5 x ULN OR direct bilirubin =\< 1 x ULN * Aspartate aminotransf…