Regular Exercise May Lower Risk of Colon Cancer's Return By 40% to 50%

Colon cancer survivors whose activities equal an hour-long walk each day may be less likely to have their cancer return and less likely to die than survivors who get little physical activity, according to a new report from the Cancer and Leukemia Group B (CALGB).

It's the first strong evidence that certain levels of activity may improve colon cancer survival rates -- and it builds on earlier studies showing that exercise helps lower the risk of developing the disease.

"This study, along with others, is a reflection that in addition to chemotherapy, there are potential lifestyle changes that we can recommend for survivorship," said lead researcher Jeffrey A. Meyerhardt, MD, MPH, of Dana-Farber Cancer Institute in Boston.

Meyerhardt presented the study findings at the American Society of Clinical Oncology Annual Meeting in Orlando last month. The results have not yet been published in a medical journal, a next step that requires experts to review and verify the research methods used. Focus on Colon Cancer Patients with Lymph Node Involvement.

The CALGB study included over 800 men and women, ages 21 - 85, diagnosed with stage III colon cancer (cancer that had spread beyond the colon to a few nearby lymph nodes but had not yet spread to other organs). After having surgery, all participants in the study went on to receive adjuvant chemotherapy, which is designed to help protect against a cancer recurrence.

Each person completed a questionnaire midway through the adjuvant chemotherapy and again 6 months after it ended. Only those who completed both questionnaires and were free of cancer at the time of the second questionnaire were eligible for the study. Their health has been followed for up to 3 years since.

Detailed information about many physical activities was collected in the later survey, when people were likely to have resumed their normal lifestyles. Activities included walking, climbing stairs, jogging, bicycling, tennis, swimming, and other aerobic exercises, as well as lower-intensity activities like yoga or stretching, and vigorous chores like lawn mowing.

When researchers checked the participants' health between 2 and 3 years later, those who reported doing moderate physical activities on a regular basis had cut their risk of cancer recurrence or death by 40% - 50% compared with the less active study members. This benefit held true despite differences in age, gender, height, or weight.

If these findings are confirmed, people with colon cancer could gain a new method to help lower their risk of recurrence -- a method that is under their own control and has many additional health benefits.

Meyerhardt's research suggests survivors would need at least 6 hours per week of moderately-paced walking at 2 - 3 mph. Or a combination of activities done for 3-6 hours per week could be enough, as long as the overall effort was about the same or greater than moderately-paced walking.

"The good news about this," said Colleen Doyle, MS, RD, director of nutrition and physical activity for the American Cancer Society, "is that the majority of people are able to walk at this pace - you don't have to feel as though you need to train for a marathon to see real health benefits."

In the study, other activities that were linked with better survival rates included at least 3 hours per week of jogging (at a pace slower than a 10 minute mile), tennis, swimming, calisthenics, and using a stair-stepping machine. Should People Begin Exercising at Diagnosis?

"We've known that exercise can have a positive effect on cancer survivors by reducing depression and anxiety, boosting self esteem, and even reducing fatigue," Doyle said. "Studies suggesting that exercise can reduce cancer recurrence and improve survival rates reinforce an important message: Dependent on ability, cancer survivors should be encouraged to be more active on a regular basis."

Meyerhardt said exercise may one day become part of a patient's prescription once diagnosed with cancer. "I think if these results are confirmed, they provide a recommendation that we (doctors) should provide patients after the diagnosis of colon cancer in addition to standard treatments."

Despite the fact that many individuals -- with cancer and without -- struggle to exercise, Meyerhardt is optimistic that results such as these will encourage physical activity. "I am hopeful for both their cancer and for other overall health benefits."