Conditions: Breast Cancer
Keywords: hormone-receptor positive tamoxifen letrozole zoledronic acid leuprolide
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 17
Healthy volunteers: no

Brief summary:
The purpose of this study is to determine the safety and tolerability of the combination of two drugs (letrozole and leuprolide) in women who have already taken tamoxifen for at least 4.5 years. Letrozole, an aromatase inhibitor (which blocks an enzyme that produces estrogen), is a drug that is FDA approved. It has been shown to reduce the risk of breast cancer recurrence in postmenopausal women with breast cancer who have been previously treated with tamoxifen. Letrozole works by stopping the production of estrogen in parts of the body other than the ovaries. Leuprolide is a drug that stops a women's ovarian cycles. This process is known as ovarian function suppression. Stopping a women's menstrual cycle may be effective against breast cancer for some patients when given as initial therapy. The combination of letrozole and leuprolide is considered a standard treatment for women with metastatic breast cancer, and is also sometimes used for treatment of premenopausal early stage breast cancer, but it has not been accepted as a standard of care treatment.

Detailed description:
* Participants will be given a monthly intramuscular injection of leuprolide. Six to eight weeks after the first leuprolide injection, participants will be instructed to begin taking letrozole pills by mouth at home each day.
* During this research study, participants will also be offered injections of zoledronic acid to preserve bone mineral density. If desire, these injections will be given every 6 months for a total of 4 injections during the course of the research study.
* The treatments in this research study may increase the risk of bone density loss, so vitamin D and calcium supplements will be recommended to participants.
* The following tests and procedures will be performed during the research study: Physical Exam (every visit); Blood tests; Urine test (beginning and end of treatment); Imaging (annual mammograms); Bone Density (DXA) Scan (beginning and end of treatment); Questionnaires (throughout the study).
* Participants will be on this study for about two years.

Arms:
arm 1: Patients will receive 2.5mg oral letrozole daily and either 7.5mg monthly of Leuprolide IM or 22.5mg every three months of Leuprolide IM. Zoledronic acid 4mg IV every 6 months x 4 will also be offered optionally.

Interventions: intervention 1: leuprolide intervention 2: letrozole intervention 3: zoledronic acid
Intervention descriptions: intervention 1: Given intramuscularly beginning on day 1 and then either 7.5 mg every month or 22.5 mg every 3 months for two years intervention 2: Taken orally once a day 6-8 weeks after initial leuprolide administration intervention 3: If desired, given intravenously every 6 months for a total of 4 injections (optional)

Protocol document: