New Report: Potential Links Between
Weight, Physical Activity and Breast Cancer Survival
There are now approximately 3.1 million breast cancer survivors living in the United States. The latest Continuous Update Project report, released earlier this month, has now identified potential links between diet, weight and physical activity and longer survival for women diagnosed with breast cancer.
In partnership with AICR, World Cancer Research Fund (WCRF) International's report found indications of links between survival and:
- A healthy body weight
- Being physically active
- Eating foods containing fiber and soy
- A lower intake of fat, particularly saturated fat
The latest report from the Continuous Update Project is the most rigorous, in-depth and systematic review of worldwide research yet conducted into breast cancer survivors and the lifestyle factors affecting their survival.
The CUP analysis includes 85 separate studies of 164,416 women and highlights growing evidence of links between a healthy BMI, physical activity, diet and all-cause mortality, breast cancer mortality, and subsequent primary breast cancer incidence.
The findings of Diet, Nutrition, Physical Activity and Breast Cancer Survivors support AICR’s recommendations that eating a plant-based diet, keeping to a healthy weight and getting regular physical activity remain the best strategies for all cancer survivors to follow. The report concludes, however, that currently available scientific evidence is still not strong enough to give concrete recommendations specifically for breast cancer survivors.
“Although it is difficult to make specific recommendations, the research suggests that women who have a healthy weight and are physically active, both before and after they are diagnosed, have a better chance of surviving a diagnosis of breast cancer and of not getting a second primary breast cancer,” said Anne McTiernan, MD, PhD, the panel lead of the CUP report and a researcher in the Public Health Sciences Division at the Fred Hutchinson Cancer Research Center in Seattle. “We need to know more about the effects of other factors on the associations between lifestyle and survival, including specific types of tumors, the stage at which a tumor is found, previous cancer treatment, and socio-economic factors.”
Previous reports from AICR and WCRF International have shown that a healthy body weight reduces the risk for eight cancers, including post-menopausal breast cancer.
The new report also found some evidence that women who eat more foods containing fiber and soy may have a lower risk of dying following a diagnosis of breast cancer, and that women eating a diet high in fat and saturated fat may have increased risk of dying following a diagnosis of breast cancer, although these findings are also still not strong enough to merit specific recommendations for breast cancer survivors.
There are several possible mechanisms to explain links between diet, weight, and physical activity with breast cancer prognosis. For example, being overweight or obese increases blood levels of insulin, estrogen and other hormones that can encourage the growth of cancerous cells. Because fat tissue is metabolically active, it produces proteins that cause inflammation, which can promote cancerous changes in cells and tissues.
And physical activity may influence breast cancer outcomes through its effects on hormones and by helping women prevent weight gain.
“We know there are many reasons for women to eat a plant-based diet and be active, both for cancer prevention and overall health,” said Alice Bender, RDN, MS, AICR Associate Director for Nutrition Programs. “For survivors, start where you are and look for small changes you can make. For example, take advantage of the times you feel best to walk or move in some way. Use pre-chopped or frozen vegetables as an easy way to boost your healthy diet.”
Today’s report on breast cancer survivors – the first CUP report to look at survivorship – has not changed AICR’s advice to the survivor community: After treatment, breast cancer survivors should follow AICR’s 10 Recommendations for Cancer Prevention, as guided by their health care professional.
Source: Krasimira Aleksandrova et al. Combined impact of healthy lifestyle factors on colorectal cancer: a large European cohort study. BMC Medicine, 2014; 12 (1): 168.
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