CHALLENGE Trial: Structured Exercise Cuts Colon Cancer Recurrence Risk by 28%, Landmark Study Finds
Key Insights
The CHALLENGE trial, published in the New England Journal of Medicine, showed that a structured exercise program reduced disease recurrence or death by 28% in stage II/III colon cancer (search) survivors over a median eight-year follow-up.
Patients in the exercise group had a 37% lower risk of death from any cause, with 90% overall survival at eight years compared to 83% in the control group receiving standard education alone.
A separate study found that patients with the most pro-inflammatory diets faced an 87% higher risk of death compared to those with the least inflammatory diets, suggesting nutrition and exercise interact to influence outcomes.
A landmark randomized controlled trial has demonstrated that a structured exercise program can significantly improve long-term survival outcomes for colon cancer (search) survivors, marking what experts describe as a turning point for the growing field of exercise oncology.
The CHALLENGE trial, published in the New England Journal of Medicine in 2025, was the first large randomized controlled study to test whether a structured exercise regimen could improve long-term outcomes for colon cancer (search) patients after completing surgery and chemotherapy. Led by Dr. Christopher Booth of Queen's University in Kingston, Canada, and conducted by the Canadian Cancer Trials Group, the study tracked 889 patients across Canada and Australia.
"The conventional pillars of cancer treatment are surgery, radiation, and chemotherapy with everything else being supportive," said Sharlene Gill, an oncologist at the University of British Columbia and a co-author of the CHALLENGE Trial. "Exercise has moved from not supporting that fight but having the ability to change the outcome of that fight."
Trial Design and Key Findings
All participants had previously undergone surgery and chemotherapy for stage III or high-risk stage II colon cancer (search). Researchers randomly assigned 445 patients to a three-year structured physical activity program, while the remaining 444 received standard health education materials. Those in the exercise group worked directly with a physical activity consultant to achieve a clear target: the equivalent of 45 to 60 minutes of brisk walking, three to four times a week.
After a median follow-up of nearly eight years, the results revealed a distinct divergence in survival rates. Disease-free survival at five years reached 80% in the exercise group compared to 74% in the education-only group. Overall survival at eight years showed 90% of participants in the exercise program were alive, versus 83% in the control group.
Patients who participated in the program had a 28% lower risk of disease recurrence, a new primary cancer, or death than those who received exercise education alone. They also had a 37% lower risk of death from any cause. According to the study authors, the magnitude of the survival benefit was similar to that seen with many approved cancer drug therapies.
The results are "remarkable," said Melinda L. Irwin, deputy director of the Yale Cancer Center and Susan Dwight Bliss professor of epidemiology and associate dean of research at Yale School of Public Health. Beyond demonstrating a statistically significant benefit, she noted, the study found an effect large enough to meaningfully improve patients' lives.
The Role of Inflammatory Diets
A second study evaluated how food choices influence survival rates in colon cancer (search) patients. Dr. Sara Char, a clinical fellow at the Dana-Farber Cancer Institute, analyzed data from 1,625 patients enrolled in a broader trial evaluating chemotherapy duration and anti-inflammatory medication for stage III colon cancer.
Char's team categorized participants into five distinct groups based on how inflammatory their self-reported diets were, using a standard empirical scoring system. Pro-inflammatory diets typically feature heavy amounts of processed meats, refined grains, and sugary drinks, whereas anti-inflammatory diets emphasize vegetables, legumes, and whole foods.
The difference in survival outcomes was pronounced: patients with the most pro-inflammatory diets faced an 87% higher risk of death than those with the least inflammatory diets. The median survival for the high-inflammation group was 7.7 years, while the low-inflammation group had not yet reached a median survival baseline by the conclusion of the study.
Notably, Char observed that regular physical activity seemed to lessen the negative impact of a poor diet, suggesting that nutrition and movement interact rather than function in isolation.
Biological Mechanisms Under Investigation
Researchers are still working to understand exactly how exercise influences cancer outcomes. Evidence increasingly suggests physical activity affects several biological pathways that help create a less hospitable environment for tumors.
"The idea is not that exercise directly 'cures' cancer on its own, but that it may help create a physiologic environment that is less favorable for cancer growth and more supportive of the body's natural anti-tumor defenses," said Irwin.
Exercise appears to strengthen the body's surveillance system by increasing the activity of immune cells—including natural killer cells and T cells—that seek out and destroy abnormal cells. One study hypothesized that exercise might alter tumor microenvironments, making cancer cells less effective at maintaining barriers that prevent immune cells from entering and destroying them.
Exercise may also counter chronic inflammation, another force that helps tumors thrive. Physical activity decreases the activity of cytokines such as IL-6 and TNF-α (search), which promote inflammation. This lowering of inflammatory signaling might create a biological environment less supportive of tumor progression, explained Irwin.
Additionally, exercise helps regulate insulin-like growth factor 1 (IGF-1 (search)), a hormone involved in cell growth that has been linked to increased cancer risk when elevated. Physical activity can also improve insulin sensitivity, helping counter a metabolic state associated with higher cancer risk and poorer outcomes.
The CHALLENGE research team now plans to analyze blood samples from participants to identify the specific biological pathways—such as shifts in chronic inflammation or immune response—driving these outcomes.
From Research to Clinical Practice
Taken together, these findings elevate diet and exercise from general wellness advice to concrete components of post-cancer recovery. While neither study definitively proves that lifestyle changes alone cause superior outcomes, and both emphasize the need to pinpoint the underlying biology, they provide actionable evidence for oncology teams.
The shift has created burgeoning interest in exercise oncology, including the 2024 formation of The International Society of Exercise Oncology and the growing number of facilities worldwide offering structured exercise programs for cancer patients. An estimated 2,100 cancer exercise programs exist in the U.S. at hospitals, university-affiliated facilities, or community settings.
At Manhattan's Memorial Sloan Kettering Cancer Center, patients can be referred to a specialized exercise oncology program as soon as they are diagnosed with cancer, said Jessica Scott, the director of the exercise oncology program. There, exercise physiologists develop individualized plans that continue through treatment and recovery, adapting recommendations based on a patient's fitness level, risk factors, and changing needs.
Yet access remains one of the field's biggest challenges. The American Society of Clinical Oncology recommends that patients engage in regular aerobic and resistance exercise during treatment, but exercise has not yet been incorporated into standard-of-care guidelines in the United States. This year, the European Society for Medical Oncology adopted exercise as guideline-therapy for localized colon cancer (search). That means insurance typically won't cover programs, so patients need to rely on institutional funding or pay out of pocket, noted Scott.
Some experts now envision a future in which an exercise prescription becomes as routine as other parts of a cancer treatment plan. As Gill emphasized, the findings suggest exercise should be integrated into standard cancer care alongside surgery, radiation, and chemotherapy.