World Cancer Research Fund regularly reviews all the latest evidence on certain risk factors and cancers as part of our Global Cancer Update Programme.
If you have any questions about the research on this page, please email web@wcrf.org and we’ll be happy to help.
As well as the latest research, where relevant we also share advice for people with cancer from our collaboration with the NIHR Cancer and Nutrition Collaboration and the BDA Oncology Specialist Group.
> Jump to our Oct 2022 review of the evidence on breast cancer mortality
In December 2022, our study found strong evidence that being physically active improves quality of life in women living with and beyond breast cancer.
Women are living longer after a diagnosis of breast cancer, due to earlier detection and improved treatment, and it is crucial that, as well as living longer, women live in good health.
According to the World Health Organization, good health refers to physical, mental and social wellbeing – it does not mean simply being disease-free. Quality of life typically refers to how “well” an individual feels (in physical, mental and social capacities) and whether they feel able to function in daily life.
This review, carried out by World Cancer Research Fund’s Global Cancer Update Programme team at Imperial College London, investigated whether physical activity improves health-related quality of life in women after a diagnosis of breast cancer. It also looked at whether there were any differences by the type, amount and timing of physical activity.
The study systematically reviewed the literature and included trials of physical activity interventions delivered before, during and after treatment, and which assessed quality of life by asking participants about their experiences and lives.
Approximately 14,500 women taking part in 79 trials (reported in 92 publications), mainly in North America and Europe, were included in the review. Overall, the results showed that physical activity improved quality of life.
The evidence was less clear on how frequency and amount of physical activity made a difference to quality of life. There was some evidence that physical activity had a greater effect on quality of life when it was started after treatment compared with during treatment (treatment here refers to primary treatment and the acute phase of adjuvant treatment, not extended use of hormonal therapy).
Independent experts found little evidence that physical activity caused any harm in this group (for example, physical activity causing injury). They were not however able to make judgements about the best type or dose of physical activity or draw firm conclusions about the impact on different aspects of quality of life.
Our findings support physical activity being routinely incorporated into clinical care. Breast cancer survivors should be encouraged to be physically active. However, women should introduce new physical activity under the supervision of healthcare professionals.
Future research should focus on understanding whether the type, amount and timing of physical activity makes a difference to quality of life outcomes, as this would allow for even more specific guidance to be developed for women.
Jodie Burdett (39), from Essex, is one of our supporters. She was diagnosed with breast cancer in 2015 and runs yoga classes for people with a cancer diagnosis. She said:
It is great to see that exercise is recommended for women living with breast cancer. Exercise and yoga helped me to adapt and reconnect to the changes in my body. My energy levels increased and, as I built up my strength and confidence, my quality of life improved as I was able to do more and was less anxious and worried.
After a cancer diagnosis, and the treatment that follows, you worry about how much exercise you can do and if it’s good for you, especially if you’ve had operations and radiotherapy. Fear can creep in. It’s important that this research is communicated: that after a cancer diagnosis physical activity is vital for both mind and body. As long as you listen to your body and don’t strive beyond your limits, you can enjoy a fulfilled life.
> Read a Q and A with Dr Helen Croker about this research
> Keeping active during cancer and cancer treatment
> Can people with cancer go swimming?
> Are there any nutrition tips that could help support my fitness goals after cancer diagnosis?
In autumn 2022, we published our review of evidence on how a woman’s risk of dying after a breast cancer diagnosis is affected by her weight, diet and physical activity. We commissioned a systematic review – examining all the published research on a particular subject – of studies up to 31 October 2021.
Many people living with and beyond a cancer diagnosis are interested in the latest research, so we’re sharing the results here. However, the evidence we found, although important, was limited. Evidence can be limited in many ways, such as:
We have complete confidence in the rigour of our review of breast cancer mortality studies, but since the evidence we found was limited, we weren’t able to make formal recommendations. However, it’s likely that following the healthy living guidelines coming out of this work will benefit women after a breast cancer diagnosis.
The review found some limited evidence that eating food that contains soy reduced a woman’s risk of death and the risk of breast cancer recurring.
The studies measured the amount of soy in women’s diets then estimated the amount of isoflavones and/or soy protein, using questionnaires given to patients. The studies didn’t distinguish between different soy food; the focus was on the overall amount in the diet.
The review also found some limited evidence that dietary fibre reduced a woman’s risk of death.
The review also found some limited evidence that women with healthy eating patterns had a reduced risk of death. In these studies, the eating patterns were low in fat and high in fibre, fruit and vegetables, and followed World Cancer Research Fund’s Cancer Prevention Recommendations.
> Should I avoid soy if I have breast cancer?
> Could soy products affect my risk of cancer?
The review found some limited evidence that doing more physical activity lowered a woman’s risk of death and the risk of breast cancer recurring.
The studies reviewed wasn’t able to didn’t look in detail at how much physical activity women with breast cancer should do – we need more evidence on what type and amount of activity, such as frequency, duration and intensity. In the absence of these details, women living with and beyond breast cancer should aim to follow national guidelines for physical activity, under the guidance of their healthcare team.
> Keeping active during cancer and cancer treatment
> Can people with cancer go swimming?
> Are there any nutrition tips that could help support my fitness goals after cancer diagnosis?
The review found strong evidence that having a higher body weight after a breast cancer diagnosis increases a woman’s risk of dying.
It’s not yet clear why a higher body weight has this affect. Possible explanations of this link relate to differences in the following between women living with obesity compared with those who have a lower BMI:
All these factors are thought to interact in a way that increases the risk of breast cancer developing and may also be associated with poorer outcomes after a diagnosis. Obesity may also alter disease characteristics, so that those living with obesity develop breast cancer that is less treatable and more likely to spread. Further studies exploring the mechanisms that underpin the links between weight and breast cancer outcomes are much needed.
> Common cancer side-effects: weight gain
With recent improvements in cancer screening, diagnosis and treatment, women with breast cancer are living longer than before. Analysing the latest evidence helps us to understand how risk factors affect a woman’s long-term health after a breast cancer diagnosis and provide evidence to governments wanting to reduce the burden of cancer.
The findings strengthen the case for women with breast cancer, supported by their healthcare team, to make positive behaviour changes. This could include eating a healthier diet and being more physically active, both of which play a role in maintaining a healthy weight. Being a healthy weight also reduces the risk of other chronic diseases such as cardiovascular disease and diabetes.
Women living with and beyond breast cancer should always consult with their healthcare team before making any changes to their diet or physical activity routine.
