New research highlights possible links between weight and physical activity in surviving breast cancer

16 October 2014

A leading cancer prevention charity has identified intriguing indications of links between diet, physical activity and breast cancer survival.

The global review of cancer prevention research by World Cancer Research Fund International’s Continuous Update Project (CUP), found indications of links between breast cancer survival and:

  • A healthy body weight;
  • Being physically active;
  • Eating foods containing fibre and soy; and
  • A lower intake of fat, particularly saturated fat.

The Continuous Update Project is the most rigorous, in-depth and systematic review to-date of worldwide research into breast cancer survivors and the lifestyle factors affecting their survival. 

The CUP reviewed 85 separate studies of 164,416 women and highlights growing evidence of links between a healthy BMI, physical activity, diet and cancer survival.

Eating a plant-based diet, keeping to a healthy weight and regular physical activity remain the best strategies for breast cancer survivors, but World Cancer Research Fund International’s expert panel of scientists believes the available scientific evidence is still not strong enough to give concrete recommendations specifically to survivors.

Dr Kate Allen, Executive Director of Science and Public Affairs at World Cancer Research Fund International, said: “Although it is difficult to make specific recommendations, the research shows some evidence of links between cancer survival, maintaining a healthy body weight, being physically active and having a healthy diet.

“The research from the Continuous Update Project indicates that women who have a healthy BMI and are physically active, both before and after they are diagnosed, have a better chance of surviving if they are diagnosed with breast cancer. But we need to rule out other factors, such as types of treatment, that might explain these findings, so our knowledge of the exact causal links between diet, weight and physical activity and breast cancer survival needs to improve.”

Having a healthy BMI helps to reduce risk of developing eight cancers including post-menopausal breast cancer, so World Cancer Research Fund International recommends checking your BMI regularly to see if you are a healthy weight.

The study also found some evidence that women who eat more foods containing fibre and soy have a lower risk of dying from the disease. There are also indications that people eating a diet high in fat and saturated fat before developing the disease may have a higher risk of dying following a diagnosis of breast cancer, although these findings are still not strong enough to base specific cancer survival recommendations on.

In 2012, 50,748 women were diagnosed with breast cancer in the UK and increasing numbers of women are surviving as methods of diagnosis and treatment improve. More than half a million (550,000) UK women are currently breast cancer survivors.

Dr Teresa Norat from Imperial College London whose team assesses and collates the research for World Cancer Research Fund International said: “Understanding the science behind the links between diet and lifestyle and surviving breast cancer is still a relatively new area of research. There are several possible reasons for the links we are seeing into diet, weight and physical activity, and breast cancer survivorship.”

We know that high body fatness is linked to an increased risk of breast cancer, but we need to know more about the effect of other factors on survival such as: previous cancer treatment, the particular types of tumours affecting overweight women, socio-economic factors and the stage at which a tumours is found.

Dr Norat added: “Cancer survival is an emerging area of research, however, more good quality research is urgently needed to fully understand the relationship between lifestyle factors, treatment and cancer survival.”

The CUP monitors and analyses global research and draws conclusions on how lifestyle factors such as diet, weight and physical activity affect the chance of developing cancer and surviving it. A panel of independent experts assesses if the scientific evidence has changed and if this impacts on the 10 Recommendations for Cancer Prevention. It has so far reported on breast, bowel, pancreatic, womb (endometrial) and ovarian cancer.

After treatment our advice to breast cancer survivors, if it fits with the specific medical advice given, is to follow our Cancer Prevention Recommendations.

For more information contact Paul Hebden on 020 7343 4273.

Notes for editors

  • For an advance copy of the full Breast Cancer Survivors CUP report please contact Paul Hebden in the WCRF Press Office. The report will be available from 16 October onwards.
  • The cancers linked to being overweight or obese are: ovarian, bowel, post-menopausal breast, endometrial, oesophageal, kidney, pancreatic and gallbladder.
  • Healthy weight = BMI of 18.5 to 24.9
  • Overweight = BMI of 25 to 29.9
  • Obese = BMI of 30 or more
  • Being overweight or obese increases blood levels of insulin, oestrogen and other hormones that can encourage the growth of cancerous cells, and because fat tissue is metabolically active, it produces proteins that cause inflammation, which can promote cancerous changes in cells and tissues.