A study published in JAMA Network Open suggests that tailored exercise strategies may be associated with improved long-term survival among breast cancer survivors, supporting the role of individualised physical activity as part of survivorship care.
While regular physical activity is widely recommended following cancer treatment, the optimal approach to exercise—particularly in terms of intensity, duration, and personalisation—remains less clearly defined. In this context, the current study used a target trial emulation design, aiming to approximate the conditions of a randomised trial, to evaluate the association between changes in physical activity and long-term outcomes.
CLINICAL SUMMARY
What was examined
A target trial emulation study evaluating the association between tailored increases in physical activity and long-term survival outcomes in women with stage I–III breast cancer.
Key findings
- Increases in physical activity (e.g., +60 minutes vigorous or +120 minutes moderate per week) were associated with reduced all-cause and breast cancer–specific mortality.
- Absolute reductions in 10-year mortality were approximately 3.1% (all-cause) and 2.4% (breast cancer–specific)
- Even modest increases in activity were associated with improved outcomes
Clinical implications
- Tailored exercise strategies may support improved long-term outcomes in breast cancer survivorship.
- Incremental increases in physical activity may be beneficial, particularly in previously inactive patients.
- Findings are observational and should inform, but not replace, evidence-based exercise recommendations pending further validation.
The analysis extended to a broader cohort of approximately 2,100 women with stage I–III breast cancer, the majority of whom were insufficiently active at baseline. Physical activity was assessed over time and linked to survival outcomes, with the investigators modelling the effects of increasing activity levels using individualised strategies that accounted for baseline activity and patient characteristics. In this framework, increases in physical activity—such as an additional 60 minutes of vigorous or 120 minutes of moderate exercise per week—were associated with lower risks of both all-cause and breast cancer–specific mortality over 10 years.
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Specifically, these increases were associated with an absolute reduction in 10-year all-cause mortality of approximately 3.1%, alongside a 2.4% reduction in breast cancer–specific mortality. Notably, even more modest increases in activity were associated with improved outcomes, suggesting that incremental changes may confer benefit.
The use of a target trial emulation approach represents a methodological strength, building on prior evidence, including findings from randomised studies such as the CHALLENGE trial, while addressing some of the limitations inherent in traditional observational analyses. However, the authors emphasise that the findings should be interpreted cautiously. As an observational study, the analysis remains susceptible to residual confounding, and causal relationships cannot be definitively established. In addition, physical activity was self-reported, which may introduce measurement bias.
Although the findings were observed across a broad survivorship population, the study was conducted within a single integrated health system and should be confirmed in other settings.
Overall, the results reinforce the role of lifestyle interventions as an important component of comprehensive cancer care. They also support a shift away from one-size-fits-all recommendations toward more tailored exercise strategies that consider baseline activity levels and individual patient capacity, with even modest increases in physical activity potentially contributing to improved long-term outcomes.
Paper: Jayasekera J, Ergas IJ, Schneider J, et al. Tailored Exercise Strategies and Mortality Among Breast Cancer Survivors. JAMA Netw Open. 2026;9(4):e265177. doi:10.1001/jamanetworkopen.2026.5177 Access online here.
