NBC News
June 1, 2025, 7:00 AM CDT
Exercise may significantly reduce the risk of colon cancer returning in patients after treatment, a new study has found. The late-phase trial, published Sunday in the New England Journal of Medicine and presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago, found that people who followed an exercise program after undergoing surgery and chemotherapy for Stage 3 or high-risk Stage 2 colon cancer could reduce risk of the cancer returning, a new cancer diagnosis or death by 28%.“We approve drugs that have the same and in some cases less of a benefit than this,” said Dr. Julie Gralow, ASCO’s chief medical officer.
The Phase 3 randomized controlled trial included nearly 900 patients in six countries. The average age was 61 and about 90% of the participants had Stage 3 colon cancer, which recurs in about 35% of patients within five years post-treatment. The researchers followed each patient for about eight years from 2009 through 2024. After they finished surgery and chemotherapy, half of the participants were enrolled in an exercise program. The other half, the control group, was given a booklet encouraging them to exercise and eat well post-recovery. The ultimate goal of the exercise program was to get people to increase their exercise up to a certain amount each week from wherever they were starting out.
That goal was a weekly increase of 10 MET hours — a unit that measures the metabolic equivalent of a task, or MET, which is the amount of energy the body uses during a task, whether it’s sitting at a desk or running at full speed. How many METs a workout expends depends on how intense and how long the workout is. For reference, an hour of brisk walking is the equivalent of about 4 MET hours.
The participants slowly worked up to their goal over the first six months of the program. For the first year, they met with a coach — either a physical therapist, a personal trainer or a kinesiologist — every two weeks to develop a personal exercise plan and do a supervised workout. After the first year was up, the participants met with their coach once a month for two more years. Each person’s exercise plan was tailored to them. Their coaches build a regimen around what types of exercise the participants liked in the past and what types of workouts would fit into their lifestyle. “What it translated to for most people is going on a brisk walk 45 minutes a day, four days per week,” said Dr. Christopher Booth, a medical oncologist and professor of oncology at Queen’s University in Ontario, Canada. Booth, who led the trial, and his team first wanted to understand whether being assigned a coach would prompt people to exercise more after finishing cancer treatment. If so, they wanted to know whether that exercise would lower the risk of their cancer returning.
The answers to both questions was yes.
Eight years post-recovery, 90% of the people in the exercise program arm of the trial hadn’t had recurrences or new cancer diagnoses, compared with 83% in the control group. Of the 445 people in the exercise group, 41 died within eight years of their cancer treatment, compared with 66 of the 444 people in the control group. People who exercised more also had lower risks of several other cancers, including breast and other colorectal cancers.
