Soyaøstrogener i behandling av overgangsplager hos kvinner med tidligere brystkreft

INTRODUCTION: After combined hormone replacement therapy was deemed unsafe by clinical reports in the 90’s, many women have turned to alternative sources for relief of their menopausal symptoms, a popular alternative being phytoestrogens from soy. As many sources indicate a possible beneficial effect of these supplements, I wanted to assess if these were safe for women with earlier low grade breast cancer (stadium I, II or III). METHODS: A systematic search was performed in PubMed reviewing clinical trials and RCT, the search was supplemented with articles mentioned in Messina et al.’s review paper, and the reference lists of earlier mentioned papers. RESULTS: After reviewing vast amounts of evidence, both epidemiological and interventional, no statistically significant proof that soy supplements, when used within the recommended doses (25-50mg/day), have any adverse effect on the breast predisposed for breast cancer were found. However, one interventional study found an increase in Ki67, a proliferation marker, in premenopausal women treated with one dose of 150mg soy isoflavones daily for 3 months. An epidemiological study also found an adverse effect in premenopausal women consuming high amounts of soy. While these findings were not statistically significant, it raises concerns that soy isoflavones may be harmful for a subset of women with earlier breast cancer. CONCLUSION: Further research should be done to investigate these findings, as soy isoflavanoids in themselves have many proven health benefits, and can be a valuable alternative for women whose breast cancer excludes them from conventional hormone replacement therapy