magnesium oxide in treating postmenopausal women with hot flashes and a history of breast cancer

Conditions: Breast Cancer; Cancer Survivor; Hot Flashes

Summary: rationale: magnesium oxide may help relieve hot flashes symptoms in women with a history of breast cancer. purpose: this randomized clinical trial studies how well a high-dose or a low-dose of magnesium oxide works compared to placebo in treating menopausal women with hot flashes and a history of breast cancer.

objectives: primary * evaluate the efficacy of magnesium oxide on hot flashes in women with a history of breast cancer. secondary * evaluate the side-effect profile of magnesium oxide in this study population. * evaluate the effect of magnesium oxide on the secondary outcomes hot flash frequencies, hot flash severities, toxicities (including diarrhea), and hot flash-related daily interference on activities. * evaluate the effect of magnesium oxide on the change of magnesium level (for the first 150 patients). outline: this is a multicenter study. patients are stratified according to age (18-49 years vs ≥ 50 years), current tamoxifen and/or selective estrogen receptor modulator (yes vs no), current aromatase inhibitor (yes vs no), and daily frequency of hot flashes (4-9 vs ≥ 10). patients are randomized to 1 of 4 treatment arms. * arm i: patients receive a low-dose of magnesium oxide orally (po) daily (qd). * arm ii: patients receive a high-dose of magnesium oxide po qd. * arm iii: patients receive a low-dose of placebo po qd. * arm iv: patients receive a high-dose of placebo po qd. in all arms, treatment continues for 8 weeks in the absence of unacceptable toxicity. some patients may continue or crossover to receive magnesium for 4 more weeks. patients complete the hot flash diary daily for 9 weeks beginning 1 week before treatment. they also complete the symptom experience questionnaire, the profile of mood states (poms), and hot flash-related daily interference scale (hfrdis) questionnaires periodically during study treatment. patients undergo blood sample collection at baseline and at the end of weeks 5 and 9 for serum magnesium level analysis.

Eligibility criteria:
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)

Keywords: hot flashes cancer survivor breast cancer