NCCTG N10C2 (Alliance): A double-blind, placebo-controlled study of magnesium supplements to reduce menopausal hot flashes.

Abstract

9508 Background: Hot flashes (HFs) are a common symptom in female breast cancer survivors that can negatively impact quality of life. Preliminary data suggest that magnesium may be an effective, low-cost treatment for HFs causing minimal side effects. Methods: A four-arm, double-blinded, placebo-controlled randomized trial was conducted. Postmenopausal women with a history of breast cancer and bothersome HFs were randomized into treatment groups of 800 mg or 1200 mg of magnesium oxide per day, or a corresponding placebo group in 2:2:(1:1) ratios. HF frequency and scores (number times severity) were measured using a validated HF diary. A one-week baseline period preceded initiation of study medication. The primary endpoint was the intra-patient difference in average hot flash score between baseline and at the end of the treatment period, comparing each magnesium arm to the combined placebo arms using a gate-keeping procedure. With a sample size of 80 patients per arm, there was 80% power to detect a differ...