Magnesium Oxide in Treating Postmenopausal Women With Hot Flashes and a History of Breast Cancer

DISEASE CHARACTERISTICS:

Women with a history of breast cancer (currently without malignant disease)
Bothersome hot flashes (defined by their occurrence ≥ 28 times per week and of sufficient severity to make the patient desire therapeutic intervention)
Presence of hot flashes for ≥ 30 days prior to study registration
Willingness to provide the biologic specimens as required by the protocol
Hormone receptor status not specified

PATIENT CHARACTERISTICS:

Women who are postmenopausal as defined by absence of a period in the past 12 months or bilateral oophorectomy

Women with at least one ovary but without a uterus should be deemed postmenopausal by either age over 55 or a combination of estrogen within a postmenopausal range (per local lab) and FSH over 40 mIU/mL
No women of childbearing potential or who are premenopausal
Creatinine clearance > 30 mL/min
Ability to complete questionnaire(s) by themselves or with assistance
ECOG performance status 0 or 1
No history of allergic or other adverse reaction to magnesium
No diabetes
No patients with conditions that are implicated in decreased absorption of magnesium (e.g., Crohn disease, ETOH abuse)
No patients who have diarrhea where magnesium might make it worse (per provider discretion)

PRIOR CONCURRENT THERAPY:

None of the following current (≤ 28 days prior to registration) or planned therapies (tamoxifen, raloxifene, or aromatase inhibitors are allowed, but the patient must have been on a constant dose for ≥ 28 days and must not be expected to stop the medication during the study period):

Antineoplastic chemotherapy (trastuzumab or lapatinib are allowed)
Androgens
Estrogens (any delivery route)
Progestational agents
No prior use of magnesium for hot flashes
No current or planned use of gabapentin (for any reasons) or antidepressants (for any reasons) or other agents for treating hot flashes (except stable dose of vitamin E is allowed as long as it was started > 30 days prior to study registration and are to be continued through the study period; soy is allowed, if it is planned to be continued at the same dose during the study period)
No current use of magnesium for any indication (except one standard multiple vitamin dose is allowed per day)
Not taking diuretics, corticosteroids, bile acid sequestrants, and other prescription and over-the-counter medications that may affect magnesium levels
No current (≤ 7 days prior to registration) or planned use of other non-drug therapies for managing hot flashes, such as acupuncture or yoga (use of these therapies for other reasons is allowed)