Breast density (a risk factor for breast cancer) and N-acetylcysteine.
A small 2012 study included 25 postmenopausal women randomized to receive either 1 to 1.5 g metformin or 400 to 600 mg of NAC over a median of 10.5 months. Mammographic breast density was measured before and after completion of the study. Both groups exhibited reductions in mammographic breast density, with the metformin group eliciting reduction in 28.5% of women and the NAC group exhibiting reduction in 27.3% of cases. Altered cell proliferation, apoptosis, and DNA repair are thought to be the mechanism for the reduction in breast density. Though this is a small study and considering that pharmacological methods for mammographic bone density are few and still considered experimental, NAC supplementation may represent a promising adjunctive natural therapy to breast cancer prevention in women with dense breast tissue.
Nearly 50% of women who undergo screening mammography are classified as having either heterogeneously or extremely dense breast tissue. Dense breast tissue is defined as a greater amount of fibrous or glandular tissue than fatty tissue in the breasts. Women with dense breast tissue have a modestly elevated risk for breast cancer and the sensitivity of screening mammography is reduced. One 2007 report states a 4--to 5-fold increased likelihood of developing breast cancer in women with dense breasts versus women with low breast density. (Boyd NF et al. Mammographic breast density and the risk and detection of breast cancer. N Engl / Med. 2007;356:227236.)
Comment: Due to these data, and some assertive women's health scientists and activists, certain states now require that women found to have dense breast tissue on screening mammography be provided a letter informing them of these findings and then encouraged to follow up with their primary-care provider to discuss risk and screening guidelines. While this is dictated by at least 22 state jurisdictions, and more to come, most physicians have yet to urge patients to get further testing. Even the American College of Obstetrics and Gynecologists (ACOG) is currently not offering guidelines to physicians, for further testing when the mammogram detects heterogeneously dense or extremely dense tissue (grade 3 and 4 density respectively).
In a recent evidence-based review, ACOG noted that "the assessment of breast density is subjective and affected by the perspective of individual radiologists" (Committee on Gynecologic Practice. Committee Opinion No. 593: Management of women with dense breasts diagnosed by mammography. Obstet Cynecol. 2014 Apr;123:910).
Their statement also indicates that "use of supplemental imaging such as ultrasound, magnetic resonance imaging, tomosynthesis, or thermography has not been associated with meaningful benefits for women found at screening to have dense breast tissue." ACOG goes on to encourage clinicians to comply with applicable state laws, and support further research on the topics but as of this writing, ACOG does not recommend use of alternative tests for dense breast tissue detected on screening mammography.
Bershtein LM, Vasil'ev DA, Kovalenko IG, et al. The influence of metformin and N-acetylcysteine on mammographic density in postmenopausal women. [In Russian.] Vopr Onto/. 2012;58(l):45-49.
by Tori Hudson, ND and
Guest coauthor Michelle Cameron, ND
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|Title Annotation:||Women's Health Update|
|Date:||Aug 1, 2015|
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