This Daily Habit Supercharges Chemo—and Could Help Colon Cancer Patients Live Longer
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Generally speaking, cancer survivors who undergo exercise routines do better than those who don't. We believe that the exercise helps improve certain conditions that increase cancer risk, such as insulin resistance.
—Daniel Landau, MD, oncologist/hematologist, medical director of virtual hematology at the Medical University of South Carolina
Like any habit, simply recommending exercise doesn’t always lead to consistent action. Being part of a structured program can provide more accountability and support in turning these findings into real, beneficial behaviors.
—Pashtoon Kasi, MD, MS, oncologist, medical director of GI medical oncology at City of Hope
In 2025, the American Cancer Society projects 107,320 new US cases of colon cancer and 46,950 cases of rectal cancer, with around 52,900 related deaths.[]
Colorectal cancer stands as the second leading cause of cancer mortality in the country. Despite surgery and adjuvant chemotherapy, approximately 30% of patients with stage III or high-risk stage II disease experience recurrence.[]
But potentially game-changing results from an international study, the CHALLENGE trial, presented at the 2025 ASCO Annual Meeting, could prompt oncologists to rethink post-treatment strategies.[]
The CHALLENGE trial
CHALLENGE was a phase 3, randomized trial that evaluated whether structured, supervised exercise after standard treatment could improve outcomes for colon cancer survivors.
Between 2009 and 2023, the trial randomized 889 patients with stage III or high-risk stage II colon cancer who had completed surgery and adjuvant chemotherapy.[][]
Participants were randomized to either a structured exercise program, with supervised sessions and personalized activity plans, or to a control group that received printed health education materials.
After a median follow-up of 7.9 years, those in the exercise group had better outcomes: 5-year disease-free survival was 80% vs 74%, and 8-year overall survival was 90% vs 83%. Cancer recurrence occurred in 93 patients in the exercise group, compared to 131 in the control group—a 28% reduction in risk.
“Those who received the structured exercise program not only met with a coach twice a month but their exercise sessions were supervised to ensure compliance,” notes Amar Rewari, MD, Chief of Radiation Oncology at Luminis Health, and Adjunct Assistant Professor of Radiation Oncology at Johns Hopkins University School of Medicine. “They were also given a specific exercise ‘prescription’ on what to do, which is very helpful because it can be intimidating to come up with an exercise plan on your own.”
How to write an 'exercise prescription'
“I am not surprised that the patients in the group that received the structured exercise program had better outcomes,” says Dr. Rewari. “It’s one thing to educate somebody on healthy practices, but the inertia of starting a new regimen and then sticking with it can be tough for anybody, let alone patients who are dealing with the aftermath of a cancer diagnosis and cancer treatment.”
Pashtoon Kasi, MD, MS, oncologist and medical director of GI medical oncology at City of Hope Orange County in California, agrees.
“Like any habit, simply recommending exercise doesn’t always lead to consistent action. Being part of a structured program can provide more accountability and support in turning these findings into real, beneficial behaviors,” Dr. Kasi says.
Features of the individualized “exercise prescriptions” tailored to each patient’s fitness level, health status, and preferences, included the following:[]
Primarily aerobic training, such as walking, cycling, or using cardio machines.
Moderate intensity, based on heart rate and perceived exertion.
Patients were encouraged to gradually build up to 150 minutes per week, consistent with public health guidelines.
Participants met with a physical activity consultant twice monthly during the first 6 months, then monthly up to 3 years. Some sessions were supervised, especially early on.
Evidence from prior studies
“In this study, people who had stage II or III colon cancer had the recommended surgery followed by chemotherapy. Then the groups were randomized to those who had a structured exercise program and those who didn't... This does confirm results we've seen in other papers,” says oncologist and hematologist Daniel Landau, MD, medical director of virtual hematology at the Medical University of South Carolina.
While these findings are specific to colorectal cancer, similar benefits have been observed across various cancer types and stages, Dr. Kasi adds.
Though CHALLENGE is the first randomized phase 3 trial to demonstrate survival benefits, previous observational and smaller trials laid the groundwork:
A Dana-Farber Cancer Institute study from 2006 showed that stage III colon cancer patients with 18–26.9 metabolic equivalent task (MET)-hours/week post-treatment had improved DFS (HR ~0.51; those with >27 MET hours had a DFS HR of ~0.55).[]
The ENERGY randomized trial (692 breast cancer survivors) demonstrated that a structured weight-loss and exercise intervention reduced body weight by 6% at 12 months and improved blood pressure and physical activity.[]
Clinical application and challenges
“Generally speaking, cancer survivors who undergo exercise routines do better than those who don't," Dr. Landau says. "We believe the exercise helps improve certain conditions that increase cancer risk, such as insulin resistance. By exercising and lowering weight, cancer risks improve. Exercise is also known to reduce inflammation and stress, both of which create pro-cancerous states.”
Current guidelines from the American Cancer Society recommend 150-300 minutes per week of moderate exercise or 75-150 minutes of vigorous-intensity exercise for cancer survivors. []
Despite the benefits, implementation remains a hurdle.
“Compared to pharmaceutical treatments, lifestyle interventions such as nutrition and exercise often don’t receive the attention they deserve," Dr Kasi says. "Cancer centers [should] prioritize overcoming barriers to offer these supportive interventions as part of comprehensive patient care.”
Dr. Rewari says the study demonstrates that just educating people about exercise is not enough. "This means hospitals and cancer clinics need to make the investment in structured exercise programs for patients.” However, he also realizes that “even if hospitals make these investments, some patients may not stick with the regimen."
Dr. Landau makes it very clear where exercise fits in, but, he says, this study doesn't show people can forgo chemotherapy in favor of exercise. "Chemotherapy still plays a very important role," he says.