Imagine battling advanced breast cancer, feeling the fatigue and side effects of treatment weighing you down. What if there was a way to fight back, not just against the disease, but against the physical toll it takes on your body? Groundbreaking research presented at the Advanced Breast Cancer Eighth International Consensus Conference (ABC8) reveals that supervised exercise can be a game-changer for patients with metastatic breast cancer, significantly boosting muscle mass and balance.
Professor Anne May from the University Medical Center (UMC) Utrecht and the Netherlands Cancer Institute, presented compelling findings from the PREFERABLE-EFFECT study. This research demonstrates that a structured, nine-month exercise program can lead to substantial improvements in muscle mass and strength, especially in the arms and legs, resulting in enhanced physical performance for individuals whose breast cancer has spread to other parts of the body. But here's where it gets controversial... Many believe that patients with advanced cancer should focus solely on rest and palliative care. This study challenges that notion, suggesting that targeted physical activity can offer real, tangible benefits.
"Until now, there has been limited evidence that physical exercise can improve muscle mass and strength in patients with metastatic cancer, partly because they were often excluded from studies," explains Professor May. This exclusion is a critical point. For too long, these patients have been overlooked in exercise-related research, leaving them without evidence-based guidance on how to maintain their physical well-being during treatment. The professor further noted treatments, combined with physical inactivity, often lead to a decline in skeletal muscle mass, negatively affecting body composition, muscle strength, and overall physical function, and that low muscle mass in breast cancer patients undergoing chemotherapy has been linked to increased treatment-related toxicities, more frequent dose reductions, poorer treatment outcomes, and decreased chances of survival. Hormonal therapy, another common treatment, is also associated with low muscle mass.
The PREFERABLE-EFFECT study, the largest of its kind, aimed to fill this gap by investigating the impact of physical exercise on patients with advanced breast cancer. It is crucial to highlight here that exercise has already been proven effective in patients with non-metastatic disease. The study was an international, randomised controlled trial involving centres from five European countries (Germany, Poland, Spain, Sweden and The Netherlands) and Australia. Between 2019 and 2022, it enrolled 357 patients with stage IV metastatic breast cancer – that is, breast cancer that has spread to distant parts of the body. Most were receiving first or second line treatment and 74% had bone metastases.
The participants were divided into two groups: one receiving standard care and the other participating in a nine-month exercise program. This specialized program included aerobic exercise, strength training, and balance exercises, all supervised by a qualified trainer twice a week for the first six months. For the remaining three months, the exercise group reduced supervised sessions to once a week, supplementing it with one unsupervised session. All participants used an activity tracker and were encouraged to engage in at least 30 minutes of physical activity daily. And this is the part most people miss... the importance of professional supervision. This isn't just about going for a walk; it's about a tailored program designed to address the specific needs and limitations of patients with metastatic breast cancer.
After six months, the results were striking. The exercise group showed significant improvements in physical performance, including enhanced balance and muscle strength at both three and six-month marks. Whole body lean mass, a key indicator of muscle mass, increased in the exercise group, while it decreased in the control group. Specifically, muscle mass was, on average, 0.79 kg higher after three months and 0.32 kg higher after six months in the exercise group compared to the control group. Interestingly, there were no significant differences in whole body fat percentage between the two groups.
The study also revealed significant increases in muscle mass in the arms and legs of the supervised exercise group. At three months, it had increased by an average of 0.6 kg and by 0.48 kg at six months, compared to the control group. Similarly, the skeletal muscle mass index, which is like body mass index (BMI) for muscles, also increased by an average of 0.22 kg/m2 after three months and 0.18 kg/m2 after six months compared to the control group. These increases are especially important because the muscles in the arms and legs are responsible for movement and load bearing; therefore, deterioration is an important indicator of skeletal muscle loss resulting in frailty. In contrast, the control group experienced a decline in muscle mass and skeletal muscle mass index in the arms and legs.
Professor May also highlighted the improvement in balance among the exercise group. Low muscle mass and strength are often linked to balance problems, which can be further worsened by therapy-induced nerve damage in the hands and feet, increasing the risk of falls. Preventing falls is particularly crucial for patients with bone metastases due to their increased risk of fractures. She shared a powerful anecdote about a patient who, initially unable to use public transportation due to balance issues, regained her independence after participating in the supervised exercise program.
"The results from our study are important since lean body mass is linked to better treatment tolerance, prognosis and overall health, and increased muscle strength correlates with improved quality of life and lower mortality risk," Professor May emphasized. "This supports the call for exercise, and specifically supervised exercise with a resistance exercise component, to be integrated as a standard component of cancer care for patients with metastatic breast cancer."
To further support patients, caregivers, and healthcare professionals, the ABC Global Alliance will launch a Physical Activity Resource Hub in early 2026. This hub will provide videos, exercise guides, and links to external resources tailored to individuals with different sites of metastasis, symptoms, and fitness levels.
Isabelle Aloi-Timeus, a cancer physiotherapist and founder of Salvati AC, emphasizes the importance of personalized, supervised, and safe exercise programs. Eva Schumacher-Wulf, a patient living with metastatic ABC, editor of Mamma Mia!, reinforced the need for targeted exercise programs that address the specific needs of individuals with advanced cancer. Professor Fatima Cardoso, medical oncologist and President of ABC Global Alliance, echoed this sentiment, stating that finding a balance between quantity and quality of life is fundamental in managing advanced breast cancer, and that Professor May's research contributes to empowering patients by enabling them to directly improve their quality of life and regain some control over the disease.
This research raises some important questions: Should supervised exercise be a standard part of care for all metastatic breast cancer patients? What are the potential barriers to implementing such programs, and how can they be overcome? Do you think that the current medical guidelines should be updated to reflect these findings? Share your thoughts and experiences in the comments below!
