Patients with stage III colon cancer who walked at an average pace six days a week or had equivalent exercise had a 51% reduced risk of having their cancer return compared to those who were less active.
As part of a study comparing two chemotherapy regimens, patients were enrolled in an evaluation of their exercise levels after treatment. Researchers compared exercise using a standardized unit called a MET or metabolic equivalent task. One MET equaled the energy expended during an hour of sitting quietly Walking at an average pace for an hour equaled 3 METS, running expended 12 METS, while swimming, bicycling, and tennis each resulted in 7 METS per hour.
To be sure that illness from cancer or chemotherapy was not effecting exercise levels, patients were questioned about their exercise activities 6 months after finishing chemotherapy for their cancer and only those who were cancer-free were included in the study.
Patients whose exercise reached 18 METS in a week had an 85 percent chance of being alive and cancer-free three years after the study questionnaire, those with less than 18 METS had a 75 percent chance of similar survival. 18 METS was equivalent to walking a mile at an average pace 6 days a week.
Both men and women benefited from exercise as did people younger and older than 60. There was no significant difference in benefits based on body mass index, number of lymph nodes, treatment received, or overall health at the beginning of treatment. Furthermore, exercise benefits after cancer diagnosis and treatment were independent of exercise habits before cancer. Additional exercise above the 18 METS improved disease-free survival even more, but after about 27 METS a week improvement reached a plateau.
Younger and leaner male patients tended to have the highest activity levels. However, the average body mass index in all activity categories was in the overweight range. Those with the highest level of activity gained less weight during the time after treatment, but at least 75 percent of patients in each category gained weight.
The research team emphasized that their data does not include the impact of exercise during or immediately after treatment. Patients in the study were assessed 14 months after initial diagnosis of colon cancer including time for surgery, surgical recovery, six months of chemotherapy, and six months after chemotherapy ended. None of the patients whose cancer recurred during that time period were included in the study.
The study, appearing online ahead of print, will be published in the August 1, 2006 Journal of Clinical Oncology.
Jeffrey A. Meyerhardt and his colleagues from the Cancer and Leukemia Group B concluded:
Beyond surgical resection and postoperative adjuvant chemotherapy for stage III colon cancer, for patients who survive and are recurrence free approximately 6 months after adjuvant chemotherapy, physical activity appears to reduce the risk of cancer recurrence and mortality.
In an accompanying editorial Wendy Demark-Wahnefried from the School of Nursing at Duke University says, “It’s time to get moving!” She reviews the evidence from the two colon cancer studies in the Journal of Clinical Oncology and similar protective effects of exercise for breast cancer survivors and suggests studies of interventions to help survivors increase exercise after treatment.