Megestrol Acetate or Levonorgestrel-Releasing Intrauterine System in Treating Patients With Atypical Endometrial Hyperplasia or Endometrial Cancer

Inclusion Criteria: * A histologic diagnosis of complex atypical hyperplasia or grade 1 endometrioid adenocarcinoma of the endometrium diagnoses within 3 months of study enrollment who strongly desire to maintain fertility * A diagnosis of endometrioid adenocarcinoma will undergo a magnetic resonance imaging (MRI) scan of the pelvis to rule out deep (\> 50%) myometrial invasion and extrauterine metastases * A negative urine or serum pregnancy test at the time of enrollment * Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and for 90 days following completion of therapy; should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately; a female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: * Has not undergone a hysterectomy or bilateral oophorectomy; or * Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months) * Willing and able to consent for treatment with office endometrial biopsies every 3 months * Ability to understand and the willingness to sign a written informed consent Exclusion Criteria: * A diagnosis of grade…