Findings indicate that even modest levels of physical activity can be beneficial.
Engaging in regular physical activity prior to a cancer diagnosis may reduce the risk of both disease progression and mortality, according to research published in the British Journal of Sports Medicine. Notably, even modest levels of physical activity appear to offer significant benefits, the study suggests.
While strong evidence supports the role of physical activity in reducing cancer-related mortality, its impact on disease progression has been less clear, the researchers note.
To investigate this further, the study examined anonymized data from the Discovery Health Medical Scheme (DHMS), South Africa’s largest open medical plan, which covers around 2.8 million individuals.
The data was linked to the Vitality health promotion program, which incentivizes healthy behaviors. Participants in the program earn points for engaging in physical activities such as workouts tracked by activity monitors, gym visits, or participation in organized fitness events.
Activity type, frequency, duration, and intensity are recorded and translated into weekly minutes of exercise.
The Vitality Program and Study Participants
In all, 28,248 Vitality programme members with stage 1 cancers, and comprehensive physical activity data for the year preceding diagnosis, were included in the study, which spanned the period 2007 to 2022. Breast and prostate cancers were the most common cancers, comprising 44% of the study total.
The length of time between initial diagnosis and disease progression, death, or exit from the study ranged from 1 month to nearly 13 years.
Cancer didn’t progress in nearly two-thirds of the total sample (65.5%), but in just over a third (34.5%) it did. And while 81% survived, 19% died before the end of the study. The average time to death was 20 months and the average time to progression was 7 months.
Activity Levels and Cancer Outcomes
Participants were categorized into three groups based on their physical activity levels in the year before diagnosis:
- None recorded: 62% of participants
- Low (≤60 weekly minutes): 13%
- Moderate to high (≥60 weekly minutes of moderate-intensity): 25%
After accounting for potentially influential factors, including age at diagnosis, sex, economic and social position, and co-existing conditions, rates of cancer progression and death from any cause were lower among those who were physically active in the year preceding their diagnosis.
The odds of disease progression were 16% lower for those who had engaged in low levels of physical activity in the preceding year than among those who hadn’t recorded any physical activity, while the odds for those who had engaged in moderate to high levels were 27% lower.
Similarly, the odds of death from any cause were 33% lower among those who had engaged in low levels of physical activity compared with those who hadn’t recorded any, and 47% lower for those who had managed moderate to high levels.
Long-Term Benefits of Physical Activity
Two years after diagnosis, the likelihood of no disease progression was:
- 74% for inactive participants
- 78% for those with low activity
- 80% for those with moderate to high activity
This trend continued over time:
- After 3 years: 71%, 75%, and 78%, respectively
- After 5 years: 66%, 70%, and 73%, respectively
Similar patterns were observed for overall survival:
- At 2 years, survival probabilities were 91%, 94%, and 95%, respectively.
- At 3 years: 88%, 92%, and 94%, respectively.
- At 5 years: 84%, 90%, and 91%, respectively.
This is an observational study, and as such, can’t establish cause and effect. And the researchers acknowledge that they weren’t able to account for other potentially influential factors, such as smoking and alcohol consumption, while the data on weight (BMI) were incomplete.
But there are several plausible biological explanations for the findings, they suggest, chief among which is the way in which physical activity strengthens immunity by increasing numbers of natural killer cells, lymphocytes, neutrophils and eosinophils.
Physical activity may also lower the progression risk of hormone-sensitive cancers, such as breast and prostate cancers, by regulating estrogen and testosterone levels, they add.
“Physical activity may be considered to confer substantial benefits in terms of progression and overall mortality to those diagnosed with cancer,” they write.
“In a world where cancer continues to be a significant public health burden, the promotion of physical activity can yield important benefits regarding the progression of cancer as well as its prevention and management,” they conclude.
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1 Comment
It may be a longitudinal study, but it still, in my view, proves the point that those who exercise, whether moderately or vigorously, have a positive attitude toward life. It would have been interesting if those participating in the study would have had some psychological questioners included.