Brendan Guercio, MD
Though previous studies have shown a link between exercise and improved outcomes in early-stage CRC, this is the first evidence to show this association in patients with non-local metastases.
The prospective cohort study nested within the National Cancer Institute (NCI)-sponsored randomized Alliance control trial included 1,231 patients with mCRC who received chemotherapy and self-reported their physical activity via a questionnaire. Researchers then determined each patient’s level of activity based on metabolic equivalent task (MET)-hours per week, which assesses energy expended during physical activity.
Overall, the patients who spent more time participating in moderate physical activities such as walking, cleaning, or gardening had reduced rates of cancer progression and death. Patients who reported an engagement in physical activity equivalent to 30 or more minutes of moderate exercise daily, or 18 or more MET-hours per week, experienced an overall survival (OS) rate of 0.81 (95% CI 0.67 to 0.98, P for trend 0.03), which represented a 19% reduction in mortality, and a progression-free survival (PFS) of 0.84 (95% CI 0.71 to 1.00, P for trend 0.03), which represented a 16% reduction in cancer progression.
The study also found that patients who spent 5 or more hours per week doing non-vigorous activity, such as walking or yoga, had a 25% reduction in mortality. However, there was no association found between vigorous activity, such as running or playing sports, and cancer outcomes.
“Patients should know that even as little as 30 minutes of moderate activity per day may improve outcomes for colorectal cancer patients,” said lead study author Brendan Guercio, MD, Brigham and Women’s Hospital.
Guercio said these findings suggest that even light activities, which many patients with mCRC may be able to participate in, can be associated with improved outcomes.
The most important question to address regarding the findings of the study was the role of confounders, Guercio said.
“In other words, the question was: is physical activity making people healthier, or were individuals who were sicker than others just exercising less?” he said.
To address this issue, regression analyses were used to calculate hazard ratios for disease progression and mortality for levels of self-reported physical activity after adjusting for potential confounders, including comorbidities, weight change over the prior 6 months, ECOG performance status, body mass index, chemotherapy received, tumor KRAS status, gender, and age.
Randomized controlled trials and more prospective clinical studies are needed to confirm the link between physical activity and outcomes in mCRC. A randomized clinical trial is currently ongoing to compare patients who exercise during treatment with those who do not, with the hope of confirming the impact of physical activity on cancer outcomes.
Guercio BJ, Venook AP, Niedzwiecki D, et al. Associations of physical activity with survival and progression in metastatic colorectal cancer: Results from CALGB 80405 (Alliance). Abstract presented at: 2017 Gastrointestinal Cancers Symposium; January 19-21, 2016; San Francisco, CA. Abstract 659.