This comprehensive analysis found strong evidence that being physically active improves quality of life in women living with and beyond breast cancer.
Breast cancer is the most common cancer globally, making up 12.5% of total cancers and more than 25% of cancers in women in 2020. Women are living longer after a diagnosis of breast cancer, due to earlier detection and improved treatment, and it’s 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.
This comprehensive analysis, carried out by the 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.
“Health-related quality of life” is considered an important outcome, especially in healthcare settings, and it is important to understand the factors influencing it. Although there are differing definitions of “health-related quality of life, it typically refers to how ‘well’ an individual feels (in physical, mental and social capacities) and whether they feel able to function in daily life.
The study systematically reviewed the literature and included trials of physical activity interventions delivered before, during or after treatment for breast cancer, and which assessed quality of life by asking study participants validated questions 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. The results from most of these trials (59 out of 92 publications) could be meta-analysed – this means they all covered broadly the same topic, so could be examined as a whole, rather than just individually.
Overall, the results showed that physical activity improved quality of life. This was seen for global quality of life and specific quality of life domains (including physical and emotional functioning).
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).
The quality of the studies was assessed using the “Cochrane risk-of bias tool for randomized trials” (RoB 2). Overall, there were some issues with bias, but this was mostly due to the quality of life measures being self-reported and because it is not possible to blind participants to their intervention allocation.
These are both common issues with these types of trials and the use of validated tools to measure quality of life goes some way to addressing this. There was some variation (heterogeneity) in the findings, but overall, there was a positive effect.
There was little evidence of publication bias – this is when the results of a study influences whether or not it should be published, rather than just distributing it, regardless of the outcome.
Independent experts – the Global Cancer Update Programme Panel – judged this evidence using pre-defined grading criteria. They found strong evidence that physical activity improved quality of life and that this was probably a causal relationship. They also 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 domains of quality of life.
There’s a substantial amount of evidence examining the role that physical activity plays after a diagnosis of breast cancer. By reviewing the evidence, this study has important implications for clinical settings and for guiding future research in this area. The key finding was that physical activity improves quality of life, especially when implemented after primary or adjuvant treatment and that there was little evidence of any harm in this group of patients with breast cancer.
The findings from this review, along with the independent Panel judgement, lend support to physical activity being routinely incorporated into clinical care. However, women should introduce new physical activity under the supervision of healthcare professionals.
The Panel also recommends that 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.
The analysis is part of our Global Cancer Update Programme, and the result of ongoing reviews of decades of evidence by world-renowned, independent experts from across the globe.
The analysis was carried out on our behalf by a team at Imperial College London, UK, and funded by our network of international charities.
People living with and beyond breast cancer should always consult their healthcare team before making any changes to their diet or physical activity routine.