Soy Foods Reported To Not Increase Risk For Breast Cancer Recurrence
Posted Apr 08 2011 9:49am
It was only two or three weeks ago that I wrote about a large population-based study of over 3,000 breast cancer survivors that looked at the possible benefits of soy foods consumption for breast cancer survivors. In that study breast cancer researchers reported that breast cancer survivors who consumed more than 16 mg of soy isoflavones daily had a 54% decreased risk of dying from breast cancer and that consumption of soy foods did not increase the risk for breast cancer recurrence.
Earlier this week, breast cancer researchers from multiple research institutions presented the results of a similar, though much larger research study at the American Association for Cancer Research 102nd Annual Meeting. For this study, researchers determined soy isoflavone intake from soy foods consumed by over 16,000 breast cancer survivors diagnosed with invasive primary breast cancer. The data for this study was collected from the After Breast Cancer Pooling Project, which included data from the Shanghai Breast Cancer Survival Study, the Women's Healthy Eating and Living Study, the Nurse's Health Study, and the Life After Cancer Epidemiology Study. Statistical methods were used to determine risk of breast cancer recurrence, risk of breast cancer mortality, and the link between these risks and soy isoflavone intake. The researchers reported
Soy isoflavone intake was much lower in U.S. breast cancer survivors (an average of 3.2 mg of soy isoflavones/day) than in Chinese breast cancer survivors (an average of 45.9 mg soy isoflavones/day).
Compared to lower levels of soy isoflavone consumption, higher soy isoflavone intakes were associated with an 11-15% reduced risk for breast cancer mortality and a 15-17% decreased risk of breast cancer risk overall.
This reduction in risk was slightly lower in U.S. breast cancer survivors.
Compared to soy isoflavone consumption levels below 0.48 mg/day, consuming more than 23 mg soy isoflavones per day was linked to a 9% decrease in breast cancer mortality and a 15% decrease in breast cancer recurrence.
The results of this study provide additional good news to breast cancer survivors who enjoy or want to enjoy the benefits of adding soy to their diets. There has been concern in the past that the mild estrogen-like effects of the soy isoflavones found in soy foods might actually increase one's risk for breast cancer or breast cancer recurrence. However, this current study as well as several other studies published in the last year suggest that consuming soy foods does not increase breast cancer risk and might actually reduce breast cancer risk. While the reduction in breast cancer mortality risk observed in this week's report is not as great as reported in the the previous study, the previous study was based only on the Women's Healthy Eating and Living Study. This week's report is much larger and as such might provide a better overall picture of the benefits of soy foods consumption for breast cancer survivors in general. In summary this new breast cancer research continues to confirm that consumption of soy foods might have benefits for breast cancer survivors and at the least does not seem to increase their risk for recurrence or mortality.