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.
People who were not enrolled in the exercise program got between 5.2 and 7.4 fewer MET hours of exercise per week — the equivalent of 1.5 to 2.25 hours of brisk walking.
“It’s not as simple as telling people to exercise,” Booth said. “We know that for many people, getting an exercise habit is very difficult. We really need [insurers] to cover this.”
The research was the first to randomize people into an exercise program who may not have otherwise exercised after cancer treatment. It builds on observational studies that have shown that people with Stage 3 colon cancer who exercise regularly live longer than those who don’t.
“There is almost no downside to exercise. It should be a part of the standard treatment for colon cancer,” said Dr. Nancy You, medical director of the young onset colorectal cancer program at the University of Texas MD Anderson Cancer Center in Houston.
It’s still not clear why regular exercise appears to have such a large effect on colon cancer recurrence, but a growing number of studies now show that exercise can decrease the risk of breast, colon and rectal cancer recurrence, sometimes by as much as 45%.
“There are potential hypotheses related to exercise’s effect on insulin, body composition and basal metabolic rate, all which can have anti-tumor effects,” said Dr. Jeffrey Meyerhardt, co-director of the Colon and Rectal Care Center at the Dana-Farber Cancer Institute in Boston.
Still, it will be challenging to help patients integrate more consistent exercise into their lives after cancer, especially if they don’t have access to a coach or were not very active prior to their cancer diagnosis. It’s also unclear what benefit exercise would have on extending the life of someone with later-stage colon cancers, which can be incurable.
“The exciting part of this is that it really does confirm the evidence that those who exercise after their diagnosis of colon cancer can lower their risk of recurrence and increase their survival,” Meyerhardt said, adding that people should understand that exercise is an additional therapy, not a replacement for the standard care.
Everyone in the trial had undergone surgery and chemotherapy prior to starting the exercise trial. For oncologists, being able to give recent cancer survivors a research-backed way to continue their recovery post-treatment is going to be an important part of patient care, Booth said.
“One of the common questions that oncologists get asked when a patient finishes chemo is, ‘What else can I do, doc?’ And this is really definitive. We can now say a structured exercise program done with a coach can improve your outcomes,” he said.
This article was originally published on NBCNews.com
