Health
New insights into the significance of exercise in colon cancer survival studies
Post-treatment physical activity reduces disparities between patients and the general populace
Constant physical exercise following treatment for stage 3 colon cancer diminishes and might even eradicate survival differences between those afflicted with cancer and individuals in a comparable age and sex demographic, as per fresh Dana-Farber Cancer Institute research.
Colon cancer ranks among the top causes of cancer-related fatalities globally. Individuals diagnosed with this illness encounter elevated rates of untimely death compared to the general populace with similar characteristics such as age and gender.
“This investigation indicates that physical activity can substantially influence long-term survival for patients,” remarked senior author Jeffrey Meyerhardt, co-director of the Colon and Rectal Care Center at Dana-Farber, which is affiliated with Harvard, and a faculty member at Harvard Medical School.
Among patients whose cancer relapsed, those maintaining low activity levels had overall survival statistics 50.5 percent lower than a corresponding general populace.
Earlier studies hinted that colon cancer survivors who engage in more physical activity post-treatment experience extended survival. This research examined data from two clinical trials sponsored by the National Cancer Institute, Cancer and Leukemia Group B — now included in the Alliance for Clinical Trials in Oncology — involving patients with stage 3 colon cancer. During both trials, CALGB 89803 and CALGB 80702, subjects underwent surgery, received chemotherapy, and were provided the opportunity to self-report lifestyle habits during and after their treatment.
In total, 2,875 patients self-reported their physical activity levels throughout the two trials. Survival rates were analyzed after a median duration of six and 5.9 years of follow-up for CALGB 89803 and CALGB 80702 respectively. Reported activity intensities were adjusted into metabolic-equivalent hours per week, or MET-hours. An individual who walks most days of the week for roughly an hour will acquire approximately 18 MET-hours of activity, Meyerhardt explained.
The researchers discovered that for patients alive three years post-treatment, those engaging in high levels of activity (18 or more MET-hours weekly) exhibited overall survival rates more aligned with those of the corresponding general populace compared to individuals with low activity levels (under three MET-hours weekly).
For example, from the data analysis of CALGB 89803, three-year survivors with minimal activity had overall survival rates 17.1 percent lower than the matched general population, while those with elevated activity levels had only 3.5 percent lower overall survival rates.
In both investigations, increased physical activity correlated with enhanced survival rates, and these advantages were observed in patients irrespective of their age at diagnosis. “Some level of exercise is preferable to none,” states Meyerhardt. “If you can’t commit to an hour, consider starting with 10 or 20 minutes.”
In a collaborative analysis of information from both trials, the researchers concentrated on the 1,908 patients who were alive without cancer recurrence after three years. Among those reporting low activity levels, overall survival rates were observed to be 3.1 percent lower than the corresponding general population. Conversely, individuals with high activity levels demonstrated overall survival rates 2.9 percent above the matched general population.
Physical activity also diminished survival discrepancies in patients whose cancer recurred within three years. A majority of tumor recurrences typically surface within two or three years after a diagnosis of stage 3 colon cancer. In such cases, treatment becomes significantly more complicated. Among patients whose cancer reappeared, those with low activity levels had overall survival rates 50.5 percent beneath a matched general populace. Meanwhile, those with the highest activity levels had overall survival rates 33.2 percent lower.
“Patients who maintained more activity witnessed improvements in survival even in cases of recurrence,” Meyerhardt noted. “And for those who did not face a recurrence, their overall survival rates appeared more favorable than those of the equivalent general populace.”
The study detailed in this article was supported by funding from the National Institutes of Health.