TERAPIAS ALTERNATIVAS PARA MENOPAUSIA EN MUJERES QUE TUVIERON CANCER DE MAMA What is the recommendation for the use of soy products, or concentrated soy isoflavones, and black cohosh in the postmenopausal woman with a previous history of breast cancer? Interest in phytoestrogens has been triggered by observations that certain populations, such as Japanese and Chinese women, who typically consume large amounts of isoflavones (20-150 mg/day), experience significantly fewer menopausal symptoms than those consuming only small amounts. Phytoestrogens have been reported to have both antiestrogenic and estrogenic activity.[1] As a supplement, isoflavones are used in a recommended dose of 40 mg/day. Black cohosh is a natural herbal remedy that is usually taken in doses ranging from 300-2000 mg 3 times daily in the dried rhizome form, or in doses ranging from 20-80 mg twice daily in a 20-mg-tablet form.[2] Although it is widely used by consumers for the treatment of menstrual disorders including postmenopausal symptoms, its mechanism of action remains unknown. Both agents have been investigated for the treatment of menopausal symptoms in peri- and postmenopausal women. A protocol for a systematic review of well-conducted studies was recently posted in the Cochrane Library to examine the use of phytoestrogens for treatment of menopausal symptoms.[3] However, the review is in progress and is not yet available. It will specifically address women over 45 years of age who use products containing high doses of phytoestrogens. Previously conducted studies of dietary phytoestrogens have suggested questionable or no benefits for hot flashes[4] and bone mineral density.[5] One study suggested improved lipid profile and blood pressure, as well as decreased menopausal symptoms in healthy perimenopausal women.[6] There is a single published study to date on the use of black cohosh in women with a history of breast cancer.[7] In this study, 85 patients (59 on tamoxifen, 26 not on tamoxifen) were randomized to receive either black cohosh or placebo. They kept diaries of hot flashes (number and intensity) over 60 days. There was no difference between the 2 groups. The authors concluded that in this group of women, black cohosh was not effective for hot flashes. Other literature had previously indicated that in healthy women without a history of breast cancer, black cohosh may reduce the incidence of hot flashes.[8,9] In summary, the literature on the postmenopausal use of isoflavones is limited at this point in time, and has been conducted with women without a history of breast cancer. There are suggestions of improvement in menopausal symptoms and cardiovascular function. The literature on black cohosh for symptom treatment in postmenopausal woman is more limited and even less conclusive. Physicians cannot at present recommend either remedy for postmenopausal women on the basis of adequately conducted trials. The anticipated Cochrane Review on phytoestrogens will provide more evidence. Hopefully, clinical practice guidelines for the use of these and other natural supplements will one day become available. References Knight D, Eden JA. A review of the clinical effects of phytoestrogens. Obstet Gynecol. 1996;87:897-904. Natural Medicines Comprehensive Database, Monograph on Black Cohosh (1995-2002; subscription). Contact: 3120 W. March Lane, PO Box 8190, Stockton, CA 95208 Lethaby AE, Kronenberg F, Roberts H, Eden J. Phytoestrogens for menopausal symptoms (protocol for a Cochrane Review). In: The Cochrane Library. Oxford: Update Software; 2002:Issue 1. Kotsopoulos D, Dalais FS, Liang YL, McGrath BP, Teede HJ. The effects of soy protein containing phytoestrogens on menopausal symptoms in postmenopausal women. Climacteric. 2000;3:161-167. Dalais FS, Rice GE, Wahlqvist ML, et al. Effects of dietary phytoestrogens in postmenopausal women. Climacteric. 1998;1:124-129. Washburn S, Burke GL, Morgan T, Anthony M. The effect of soy protein supplementation on serum lipoproteins, blood pressure, and menopausal symptoms in perimenopausal women. Menopause. 1999;6:7-13. Jacobson JS, Troxel AB, Evans J, et al. Randomized trial of black cohosh for the treatment of hot flashes in women with a history of breast cancer. J Clin Oncol. 2001;19:2739-2745. Foster S. Black cohosh (Icimicifuga recemosa):a literature review. Herbaalgram. 1999;45:35-49.
Posted on: Wed, 07 Aug 2013 18:38:24 +0000
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