A review of the literature

Abstract
Introduction
Soy Consumption and Risk of Recurrence: Review of Epidemiological Studies
Evidence suggests there is no increased risk of recurrence for any subpopulations of breast cancer survivors.
Discussion
Conclusion
Study Name and/ or Author |
Year |
Participants and |
Highest intake groups |
Some Foods Contributing to Intake |
Outcomes (p value) |
Life After
Cancer Epidemiology (LACE) Guha, et al.
|
2009 | 1,954 women in U.S.; Stages I(>1cm)-IIIA; premenopausal and peri/post menopausal; ER+/PR+, ER+PR-, ER- PR+, ER-/PR-; tamoxifen use: never, current and past; diadzein, genistein and glycetin evaluated separately and together |
Diadzein >1.453 mg/day |
Soy sauce, powders and drinks, tofu, diet bars, soy milk (several others that had nominal contribution) |
A significant reduced risk of breast cancer recurrence in postmenopausal tamoxifen users in the highest quintile of diadzein intake(P=0.008). A trend for reduced recurrence for postmenopausal women with increasing amounts of soy isoflavones diadzein (P=0.08) and glycetin (P=0.06). Overall and disease related mortality was not evaluated. |
Shanghai
Breast Cancer Survival Study (SBCS) Shu, et al.
|
2009 | 5,033 women in Shanghai, China; Stages 0–IV, and “unknown”; premenopausal and peri/post menopausal; ER+ or ER- , and PR+ or PR-; tamoxifen use: yes or no; soy protein; total isoflavones |
Soy protein
>15.31 g/d Isoflavones
>62.68 mg/d |
Tofu, soy milk, fresh soy beans, “other soy products” |
Inverse association with |
Kang, et al. | 2010 | 254 women in China; Stages I-III; pre and post menopausal; ER+/PR+, ER+/PR-,ER-/PR+; all participants were on tamoxifen (n=438) or anastrozole(n=86) |
Total isoflavones >42.50 mg/d |
Soy milk, tofu, soy flour |
The risk of recurrence in ER+/PR+ post-menopausal women in the highest quartile of isoflavone intake was significantly lower than the lowest quintile (P=0.02). Women taking anastrazole and in the highest quartile of intake had a significantly lower risk of recurrence than those taking anastrazole and in the lowest quartile (P=0.005). |
Womens
Healthy Eating and Lifestyle (WHEL) Caan, et al.
|
2011 | 3,088 women; stages I–III; premenopausal and peri- /postmenopausal; ER+/PR+ and ER-/PR- disease; tamoxifen current, never, and past users; total isoflavones |
Total isoflavones= 16.33–86.9 mg/day |
Tofu, soy milk and “additional foods” |
Overall mortality decreased with increasing isoflavone intake (P=0.02); Trend toward lower mortality in those consuming isoflavones and ever using tamoxifen was strong (P=0.05); non- significant trend for reduced recurrence with increasing intake (P=0.47) |
Zhang, et al | 2012 | 616 women; stages 0–II and III–IV; peri- /postmenopausal and premenopausal; ER+ or ER-; tamoxifen use either yes or no |
Soy protein
intake >13.03 g/d Total
isoflavone >28.83 mg/day |
Tofu, processed soy products, soy milk, bean curd, whole soybeans |
An average intake of soy isoflavones above 17.3 mg/day reduces breast cancer mortality by 36%– 38%. (no P value given). This benefit was independent of ER status. |
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