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Mein Konto
Relation
Guy DE, Vandersluis A, Klotz LH, et al. Total energy expenditure and high-intensity physical activity are associated with a lower likelihood of reclassification in men under active monitoring. (Link removed). 2018;21(2):187-195.
Draft
Retrospective comparative study
Objective
To examine the association between vigorous physical activity and disease progression in men under active surveillance for prostate cancer.
Participant
This study combines data from 2 cohorts of men. One group was recruited from Sunnybrook Health Sciences Center in Canada (SHSC) and the second group was recruited from Royal Marsden Hospital in the United Kingdom (RMH). The SHSC group consisted of 131 men with favorable risk prostate cancer and the RMH group consisted of 112 men with similar favorable risk prostate cancer.
These 2 groups were divided into 2 subgroups: a) those who underwent active surveillance and b) those who were initially treated with active surveillance but were later classified into higher risk disease and subsequently underwent radical treatment. Those from both hospitals whose cancer progressed and were switched to radical treatment were “reclassified.”
Study parameters assessed
Physical activity was recorded through questionnaires. The association with physical activity was examined as a variable for risk of reclassification of status from monitoring to treatment. Demographic and lifestyle covariates were also analyzed to assess potential confounding and modification of the training effect.
Key insights
Total physical activity (recreational exercise plus work-related exercise) was inversely associated with the likelihood of reclassification during active surveillance (PTrend = 0.027). The trend for an inverse association observed only with recreational exercise did not reach statistical significance (PTrend = 0.30). Men who participated in weekly vigorous physical activity were significantly less likely to be reclassified than men who did not (odds ratio [OR]: 0.42; 95% confidence interval [CI]: 0.20-0.85). These inverse associations with overall exposure were only significant when data from both hospital cohorts were added. When each cohort was examined separately, the associations were only strong trends. Vigorous, high-intensity physical activity was significantly associated with a reduction in the likelihood of reclassification in both cohorts.
Practice implications
It is now increasingly common for men diagnosed with prostate cancer with a low risk of progression to delay radical treatments (radiation or surgery) and instead simply wait and see whether the disease progresses, a strategy known as active surveillance.1This study is the first to examine the benefits of exercise for men with prostate cancer who are under active surveillance, and the results suggest they will benefit from exercise. Prostate cancer often defies our educated guesses about what will or won't benefit, so we prefer not to make assumptions based on other cancers.
The bottom line I want these patients to hear and remember is that men who exercise vigorously every week have a 58% lower risk of disease progression than men who don't.
Based on this study, we should encourage men to exercise under active supervision, and these results suggest that intense exercise provides greater benefit.
Several mechanisms have been proposed to explain the effects of exercise on prostate cancer progression.2Increased physical activity reduces the availability of androgens and insulin-like growth factors.3.4These hormones stimulate androgen receptors on prostate tumor cells, triggering cell proliferation and cancer progression.5There is also evidence that physical activity reduces the number of androgen receptors present on tumor cells.6
This was not a perfect study. It was retrospective and relied on patient recall for exercise intensity, duration, and frequency. It also relies on patient recall to account for possible confounding factors, particularly other lifestyle factors such as smoking or diet that could influence risk. However, until refuted by larger, more carefully conducted studies, these are our only data that specifically address the risk of physical activity and prostate cancer progression in the active surveillance population.
The bottom line I want these patients to hear and remember is that men who exercise vigorously every week have a 58% lower risk of disease progression than men who don't. Rounding these numbers for convenience, one could say, “Exercise reduces the risk of disease progression by more than half.”