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 = 9 g/dL
• Serum creatinine = = 60 mL/min using Cockcroft-Gault equation for patients with creatinine levels > 1.5 x institutional upper limit of normal (ULN)
• Total bilirubin = = 3000/mcl
• Platelets >= 100,000/mcl
• Able and willing to take oral medications
• Ability to understand and the willingness to sign a written informed consent document
• Body mass index (BMI) > 20

Exclusion Criteria

• Participants who had curatively treated invasive malignancies for which all treatments ended within 1 year prior to the study (with the exception of basal cell or squamous cell carcinoma of the skin)
• Not a surgical candidate or surgery is not scheduled within 43 days from starting the study drug
• Receiving any other investigational agents
• Any gastrointestinal condition causing malabsorption or obstruction (e.g. celiac sprue, gastric bypass surgery, strictures, adhesions, history of small bowel resection, blind loop syndrome)
• Has been on any hormonal treatment (including progestin-containing intrauterine device [IUD]) for CAH/EIN or low grade (grade 1 or grade 2) endometrial carcinoma in last 3 months
• Use hormone replacement therapy (including systemic or topical estrogen, progesterone, or testosterone based medication) or/and phytoestrogen supplements (i.e. black cohosh) or has been on progestin (including progestin containing IUD), tamoxifen or aromatase inhibitor within the prior 3 months
• Concomitant use of strong CYP3A4 inducers such as rifampicin, phenytoin, carbamazepine, phenobarbital or St. John's wort as these may significantly reduce the availability of exemestane
• Known hypersensitivity to exemestane or its excipients
• Known intercurrent illness or psychiatric illness/social situations that will limit compliance with study requirements
• Evidence or high suspicion of metastatic disease at enrollment
• Women with severe bone density issues/osteoporosis (defined as any medical treatment for osteoporosis, and/or a T-score of -2.5 or lower, and/or history of fracture of the hip or spine)
• Unwilling or unable to undergo research biopsy during the baseline (pre-surgical) clinic visit, or inadequate research biopsy obtained during the baseline (pre-surgical) clinic visit (determined by the gynecologic oncologist at the time of the subject's pelvic exam)