A new study published in the Journal of Clinical Oncology compared the association between physical activity and overall survival (OS) and progression-free survival (PFS) rates of patients with metastatic colorectal cancer. While exercise did not significantly impact OS, the findings suggest that these patients may prolong PFS through physical activity. Just 30 minutes a day of moderate physical activity was associated with a 27% reduction in treatment-related toxicities.
“Regular physical activity is associated with reduced risk of recurrence and mortality in patients with nonmetastatic colorectal cancer. Its influence on patients with advanced/metastatic colorectal cancer (mCRC) has been largely unexplored,” the study authors wrote.
The study included patients enrolled in a phase 3 study of chemotherapy for advanced colorectal cancer. One month after initiating treatment, these patients were invited to answer questions regarding their two-month physical activity history. These responses were used to determine metabolic equivalent task (MET) hours per week to quantify physical activity. Vigorous activities included running, biking, tennis, lap swimming, and tennis, and non-vigorous activities were those such as walking, climbing stairs, and yoga.
OS was the study’s primary outcome, while PFS was a secondary outcome, along with first grade 3 or greater treatment-related adverse events (AEs). Patients whose cancer progressed or who died within 60 days of assessment were excluded.
Final analysis included 1,218 patients. Patients who participated in at least 18 MET hours per week, compared to those with less than three weekly MET hours, had an adjusted hazard ratio (aHR) for OS of 0.85 (95% confidence interval [CI], 0.71 to 1.02; PTrend = 0.06); for PFS, the aHR was 0.83 (95% CI, 0.70 to 0.99; PTrend= 0.01). Those engaging in at least nine weekly MET hours, compared to those who did not, had an aHR for grade 3 or greater treatment-related AEs of 0.73 (95% CI, 0.62 to 0.86; PTrend < 0.001).
“What we found was that people who engaged in some type of physical activity had a statistically significant improvement in progression-free survival (PFS),” said senior study author Jeffrey A. Meyerhardt, MD, MPH, of Dana-Farber, in a press release. “While there may also be an impact on overall survival, it was not statistically significant – and should be studied further.”
“Physically active patients in our study also appeared to tolerate chemotherapy better,” said first author Brendan Guercio, MD, who was a hospitalist at Brigham and Women’s at the time of the study. “Total physical activity equivalent to 30 or more minutes of moderate daily activity was associated with a 27 percent reduction in severe treatment-related toxicities.”
When Is It Okay to Exercise?
Breastcancer.org notes that there are certain circumstances in which patients on chemotherapy should avoid or modify exercise:
- Patients with extreme fatigue, anemia, or ataxia should not exercise
- Patients with a dangerously low white blood cell count should not exercise in public places until their white blood cell count returns to a safe level
- Patients experiencing neuropathy or tingling/numbness should be extra cautious and may consider exercising with a spotter
- Patients whose cancer has spread to the bone have a higher risk for fracture and should consult with their doctor, and perhaps a physical therapist, to determine what exercises/intensities are safe
- Patients whose chemotherapy could affect their heart should speak with their doctor and possibly a cardiologist to discuss potential exercise modifications
Most of these precautions also apply to patients after their chemotherapy is complete, the website notes. In any circumstance, it is recommended patients speak with their doctor before beginning any exercise regimen.
