Denosumab and MRI Breast Imaging

Inclusion Criteria:

* Pre or postmenopausal women with first incidence of early stage (stages 0 - III) breast cancer who have completed all treatment and are cancer-free, which includes women at high risk for developing invasive cancer i.e. having a breast biopsy positive for atypical ductal or lobular hyperplasia or carcinoma in situ.
* Age ≤ 75 years
* 44 patients will be accrued as follows: a) 22 evaluable patients will be premenopausal as defined as regular menses (24-38 days) b) 22 evaluable patients will be postmenopausal as defined by a history of amenorrhea for at least one year or hormone levels (estradiol/FSH) consistent with menopause if post-hysterectomy status, or history of surgical/medical castration.
* Normal serum calcium or albumin-adjusted serum calcium between 2.0 and 2.9 mmol/L (8.0-11.5mg/dL).
* Adequate vitamin D level (25-hydroxy vitamin D level \> 20 ng/mL)
* Currently on no active treatment for breast cancer and at least 3 months post all the treatments, with the exception of aromatase inhibitors (exemestane, anastrozole, letrozole)
* No prior or current use of IV bisphosphonates
* No current use of oral bisphosphonates
* Patients must have an unaffected, non-irradiated contralateral breast
* Significant breast density as determined by mammography and defined by the descriptive terms scattered fibroglandular tissue/densities, heterogeneously dense, or mostly dense tissue in the mammography report.
* Adequate renal function defined as a serum creatinine \< 1.5 x ULN or CrCl \> 30mL/min
* A willingness and ability to follow the study protocol, as indicated by provision of informed consent to participate
* Willingness to being tested for current pregnancy and use of birth control while being treated with denosumab (pre-menopausal women only)

Exclusion Criteria:

* Age \> 75 years
* Subject has known sensitivity to any of the products to be administered during the study (e.g., mammalian derived products, denosumab, calcium, or vitamin D).
* Patients have prior history or current evidence of osteonecrosis or osteomyelitis of the jaw.
* Patients have active dental or jaw condition which requires oral surgery, including tooth extraction.
* Patients have non-healed dental or oral surgery, including tooth extraction.
* Patients with planned invasive dental procedures
* Subject is pregnant or breast feeding, or planning to become pregnant within 5 months after the end of the treatment
* Subject is of child bearing potential and is not willing to use, in combination with her partner, highly effective methods of contraception or abstinence during treatment and for 5 months after the end of treatment
* Active infection with Hepatitis B, Hepatitis C, or Human Immunodeficiency virus (HIV)
* Any condition or disorder that compromises the ability of the subject to provide written informed consent and/or comply with study procedures
* History of claustrophobia
* Have electrically, magnetically, or mechanically activated implants including cardiac pacemaker, cochlear implants, magnetic surgical clips or prostheses.