Although rates of new cases have steadily declined over the past two decades, colorectal cancer remains the third leading cause of death among all cancers in the United States. Rates of colorectal cancers are highest in African American men and women, and increase significantly after the age of 85. Currently, the overall five-year survival rate for the cancer is 65%, however, in the case of advanced metastatic tumors, the five-year survival rate is 14%.
 Walking and other light physical activity may help extend the survival time of patients with advanced colorectal cancer, according to new research published in the Journal of Clinical Oncology. Furthermore, patients who engage in physical activity may experience a statistically significant improvement in progression-free survival, according to authors of the accompanying news release.
Association of Physical Activity with Survival and Progression of Colorectal Cancer
Regular physical activity is associated with reduced recurrence and mortality in patients with non-metastatic colorectal cancer, however, the relationship between exercise and survival and progression rates  in cases of advanced or metastatic colorectal cancer have remained unknown. Lead author Dr. Jeffrey A. Meyerhardt from the Dana-Farber Cancer Institute and his team conducted a prospective cohort study based on data from a National Cancer Institute-sponsored phase III trial of systemic therapy for metastatic colorectal cancer patients. Aiming to uncover the impact of physical activity on advanced types of the cancer, researchers surveyed 1,218 colorectal cancer patients one month after chemotherapy initiation using a questionnaire that reported average physical activity levels over the previous two months.
 Based on participant responses, the team calculated metabolic equivalent task-hours per week to quantify the amount of physical activity reported. Vigorous activity, such as running, biking, tennis, skiing, or swimming, was included as well as non-vigorous activity – including climbing stairs, walking, or yoga. The primary outcome of the study was overall survival, while secondary outcomes included progression-free survival (PFS) and first grade 3 or greater treatment-related adverse events. In order to minimize confounding variables – in this case, poor or declining health – the authors excluded patients who experienced progression or died within 60 days of the activity questionnaire and used Cox proportional hazards regression analysis adjusting for comorbidities and known prognostic factors.
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Exercised Tied to Health Benefits
 The study’s results revealed that even low-intensity exercise had a positive impact on patient health; low-impact activity, such as walking four or more hours a week, was tied to a nearly 20% reduction in disease progression and death. Patients who engaged in physical activity had a statistically significant improvement in progression-free survival rates and although the data were not statistically significant, greater physical activity may have contributed to the lengthening of overall survival for patients. The study found that patients who exercised more than 18 MET-hours each week had a 15% higher chance of survival from any cause, compared with those who exercised fewer than three MET-hours – although, researchers maintain that these findings may be a result of chance. In addition, physically active patients in the study were better able to tolerate chemotherapy, revealing a 27% reduction in severe treatment-related toxicities associated with 30 or more minutes of daily exercise.
 Researchers underscore the fact that chemotherapy remains the primary treatment method for these patients. While routine physical activity can be viewed as a beneficial adjunct therapy, it should never replace systemic therapy. While some of the results were not statistically significant, the implications of the study emphasize the potential health benefits associated with regular exercise in patients with advanced colorectal cancer. Further investigation is needed to help validate these results, however, the latest findings support encouraging patients with colorectal cancer to engage in regular physical activity in order to improve outcomes and enhance quality of life.
