Hot flashes are a common symptom in breast cancer survivors that can negatively impact quality of life. Preliminary data suggested that magnesium might be used as an effective low-cost treatment of hot flashes with minimal adverse effects.
A four-arm, double-blind, placebo-controlled, randomized trial was conducted. Postmenopausal women with a history of breast cancer and bothersome hot flashes were randomized into treatment groups of magnesium oxide 800 or 1,200 mg daily or corresponding placebo groups at a 2:2:(1:1) ratio. Hot flash frequency and hot flash score (number × mean severity) were measured using a validated hot flash diary. A 1-week baseline period preceded initiation of study medication. The primary endpoint was intrapatient difference in mean hot flash score between baseline and treatment periods, comparing each magnesium group with the combined placebo groups using a gatekeeping procedure. Results were analyzed using repeated-measures and growth curve models on weekly hot flash scores based on a modified intent-to-treat principle.
Two hundred eighty-nine women enrolled between December 2011 and March 2013. Study groups were well balanced for baseline characteristics. Mean hot flash scores, mean hot flash frequencies, and associated changes during the treatment period were similar for each group. An increased incidence of diarrhea and a corresponding lower incidence of constipation were reported in magnesium arms compared with placebo. No statistically significant difference in other toxicities or quality-of-life measures was observed.
The results of this trial do not support the use of magnesium oxide for hot flashes.
From the 1Virginia Commonwealth University, Richmond, VA; 2Alliance Statistics and Data Center, Mayo Clinic Rochester, Rochester, MN; 3Johns Hopkins Medical Institutions, Baltimore, MD; 4University of Michigan School of Nursing, Ann Arbor, MI; 5Colorado Cancer Research Program, Denver, CO; 6Wichita Community Clinical Oncology Program, Wichita, KS; 7Metro-Minnesota Community Clinical Oncology Program, St Louis Park, MN; 8Michigan Cancer Research Consortium, Ann Arbor, MI; 9Illinois Oncology Research Association Community Clinical Oncology Program, Peoria, IL; 10Grand Rapids Clinical Oncology Program, Grand Rapids, MI; and 11Mayo Clinic, Rochester, MN.
Received July 24, 2014; revised and accepted September 16, 2014.
The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.
This study was orally presented at the 2014 American Society of Clinical Oncology Annual Meeting and was the recipient of an American Society of Clinical Oncology Fellow Merit Award.
Funding/support: This study was conducted as a collaborative trial of the North Central Cancer Treatment Group and Mayo Clinic and was supported in part by Public Health Service grants CA-25224, CA-37404, CA-35431, CA-35267, CA-63848, CA-35113, CA-35195, CA-35101, CA-37417, CA-35090, CA-35448, CA-35119, CA-35103, CA-35415, and CA-63849. The study was also supported, in part, by grants from the National Cancer Institute to the Alliance for Clinical Trials in Oncology (Monica M. Bertagnolli, MD, Chair; grant CA31946) and to the Alliance Statistics and Data Center (Daniel J. Sargent, PhD; grant CA33601). Additional participating institutions include the following: Marshfield Clinical Research Foundation, Minocqua, WI (Matthias Weiss, MD); Medical College of Georgia, Augusta, GA (Anand P. Jillella, MD); Carle Cancer Center Community Clinical Oncology Program (CCOP), Urbana, IL (Kendrith M. Rowland Jr, MD); Missouri Valley Cancer Consortium, Omaha, NE (Gamini S. Soori, MD); St Vincent Regional Cancer Center CCOP, Green Bay, WI (Anthony J. Jaslowski, MD); Hematology and Oncology of Dayton Inc, Dayton, OH (Howard M. Gross, MD); Sanford Cancer Center Oncology Clinic, Sioux Falls, SD (Miroslaw Mazurczak, MD); Virginia Mason CCOP, Seattle, WA (Craig R. Nichols, MD); Geisinger Clinic and Medical Center CCOP, Danville, PA (Maged Khalil, MD); Iowa Oncology Research Association CCOP, Des Moines, IA (Robert J. Behrens, MD); Meritcare Hospital CCOP, Fargo, ND (Preston D. Steen, MD); Lehigh Valley Hospital, Allentown, PA (Suresh Nair, MD); Upstate Carolina CCOP, Spartanburg, SC (James D. Bearden III, MD); Columbus CCOP, Columbus, OH (J. Philip Kuebler, MD, PhD); Toledo Community Hospital Oncology Program CCOP, Toledo, OH (Rex B. Mowat, MD); Heartland Cancer Research CCOP, St Louis, MO (Alan P. Lyss, MD); Montana Cancer Consortium, Billings, MT (Benjamin T. Marchello, MD); University of New Mexico, Albuquerque, NM (Zoneddy R. Dayao, MD); Northern Indiana Cancer Research Consortium CCOP, South Bend, IN (Robin T. Zon, MD); CentraCare Clinic, St Cloud, MN (Donald J. Jurgens, MD); Cancer Care Associates, Tulsa, OK (Alan M. Keller, MD).
Financial disclosure/conflicts of interest: None reported.
Address correspondence to: Charles L. Loprinzi, MD, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905. E-mail: firstname.lastname@example.org