In a study linking physical activity with improved cancer outcomes, researchers discovered that engaging in regular exercise before a cancer diagnosis significantly enhances the likelihood of survival and reduces the risk of cancer progression. The research, conducted on participants from the Vitality program associated with the Discovery Health Medical Scheme, revealed that individuals with moderate to high levels of physical activity have an 80% chance of avoiding death or further cancer advancement two years post-diagnosis. In contrast, those with no reported physical activity had a 74% chance of remaining stable.
The study, however, faced limitations due to insufficient data on body mass index (BMI) and other variables like cancer treatment completion, weight, and smoking habits. This lack of comprehensive data could affect the association between exercise and prognosis.
“There were several drawbacks to the study: It only collected exercise data from before diagnosis. We have no idea what these patients did afterwards […] While the measured exercise was likely accurate, it didn’t capture all that people do. So, for example, patients who had physically active jobs but didn’t wear watches that capture movement would have been inaccurately classified as doing no physical activity. The data support this since 60% were classified as having no physical activity. Even walking to your fridge or car or job entails some activity, so this study would have vastly underestimated amounts of activity.”
Participants in the study were individuals with stage 1 cancer who had been enrolled in the Vitality program for at least one year before their diagnosis. Physical activity levels were categorized into none, low, and moderate to high, with low activity defined as 1-59 minutes of exercise per week and moderate to high activity as one hour or more weekly.
The research highlighted that only 40% of participants engaged in some form of physical activity. Among these, those with moderate to high levels had a 95% chance of survival when considering all-cause mortality, compared to a 91% chance for those with no activity. The findings underscore the potential role of exercise as a preventative measure against cancer progression and mortality.
“With cancers being diagnosed earlier and an increasing incidence, accessible interventions that may positively influence prognosis are more relevant than ever. Knowing that as little as 60 minutes of regular weekly exercise may reduce the likelihood of cancer progression by 27% and death by 47%, should encourage all doctors to use exercise as medicine.”
The study's results suggest that even limited physical activity can be beneficial, aligning with previous findings that regular exercise before a cancer diagnosis correlates with reduced risks of progression and death. Although promising, the implications of these findings are limited to a specific demographic—those with private health insurance access in South Africa, predominantly individuals of white and Asian descent.
“this study confirms the benefits of even relatively small amounts of physical activity but we should encourage adherence to the WHO [World Health Organization] guidelines of 300 minutes per week of moderate intensity exercise for all of its well-described benefits.”
The data set was derived from an insurance database, which was not initially intended for research purposes. This limitation resulted in gaps regarding other potentially influential variables.
“The population was from an insurance database […] The database was developed for insurance, not research. So other variables that could explain associations between exercise and prognosis (completion of cancer therapies, weight, smoking, etc) were largely not available,” said McTiernan.
Leave a Reply