Nutrition research in diet and breast cancer has typically focussed on cancer prevention, but now studies are also looking at the links between diet and cancer survival.
Breast cancer survivors in the UK
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.
Can dietary factors improve survival?
Whilst we know that there are associations between lifestyle factors and the chance of surviving breast cancer after diagnosis, a recent World Cancer Research Fund report concluded that the evidence is still too unclear to make specific recommendations for breast cancer survivors.
The first Continuous Update Project (CUP) review of the research into diet, weight, physical activity and its impact on breast cancer survival confirmed indications of links with:
- A healthy weight
- Regular physical activity
- Eating foods containing fibre
- Eating foods containing soy
- A lower intake of fat, and in particular saturated fat
The CUP was able to draw on 85 separate studies of 164,416 women, but we still need to know more.
The association between survival and body weight
The evidence was consistent in showing an association between body fatness, lifestyle and breast cancer survival, but there may be several reasons for this. Many factors might influence survival, and currently the evidence cannot distinguish clearly which ones are responsible. Even for Body Mass Index (BMI), where there was a consistent statistical link between being overweight or obese and poorer outcome, there wasn’t enough information on the other possible factors to clearly implicate body fatness itself as the reason for the worse outcome.
There are several “confounding” factors, factors which distort the actual relationship between the lifestyle factor, like weight, and survival. One is the type of breast cancer treatment. Different treatments that are themselves related to BMI may influence cancer survival. Another factor is the role of different tumour types, which differ with BMI. Socio-economic factors also link to BMI and can influence breast cancer survival, for example, by impacting on access to healthcare. Yet another factor may be the stage at which a tumour is found.
More research needed, but it supports healthy eating
We do not yet fully understand how these factors may affect the relationship between lifestyle and breast cancer survival, and further research is needed before more concrete recommendations are made. But, in any case, the indications in the report support general eating advice – to maintain a healthy weight, be physically active, reduce saturated fat and increase fibre. This may well help your health whether you are a breast cancer survivor or not.
