Workouts seem to release body chemicals that improve cancer survival and limit recurrence
From Scientific American- November 2025 by Lydia Denworth, edited by Josh Fischman
Summary: from Jay K. Harness, MD, FACS
Exercise is emerging as a genuine therapeutic modality in oncology—one that not only improves quality of life but also directly extends survival and lowers recurrence risk across multiple cancer types. Long considered an adjunct to standard biomedical treatments, physical activity is now being recognized as a clinically potent intervention in its own right.
A landmark randomized controlled trial led by Dr. Kerry Courneya at the University of Alberta, published in the New England Journal of Medicine (2025), followed more than 800 patients with stage II–III colon cancer for ten years. Those assigned to a structured exercise program—integrated with their standard oncology care—experienced a 28% reduction in cancer recurrence, new cancers, or death compared with controls who received only educational materials. These results were powerful enough to earn a standing ovation at the 2025 American Society of Clinical Oncology (ASCO) meeting, reflecting a paradigm shift: exercise is now being discussed alongside surgery, chemotherapy, and targeted agents as a core component of cancer treatment
Beyond colon cancer, a 2025 longitudinal study of over 90,000 cancer survivors demonstrated that regular moderate to vigorous activity (150–300 minutes per week)—such as brisk walking—significantly improved survival across at least ten cancer types, including breast, prostate, lung, and endometrial cancers. Even modest exercise levels conferred benefit, though higher intensities yielded additional gains. These findings reinforce global exercise-oncology guidelines advocating structured, sustained physical activity throughout survivorship
Biological Mechanisms and Therapeutic Pathways
Exercise induces multifaceted biological changes that may act synergistically to suppress tumor progression. Key mechanisms include:
- Reduced systemic inflammation, which helps prevent tumor-promoting microenvironments.
- Improved insulin sensitivity, reducing hyperinsulinemia—a growth driver for many cancers.
- Myokine release: Skeletal muscles release cytokine-like proteins that can inhibit tumor cell proliferation. Studies show serum rich in myokines suppresses prostate cancer cell growth, and physically active patients have markedly higher post-exercise myokine levels.
- Immune activation: Exercise mobilizes natural killer (NK) cells and cytotoxic T lymphocytes, critical immune effectors in tumor control. Preclinical mouse models show exercise can reduce tumor incidence and growth by >60%, while early human trials (e.g., in esophageal and lung cancer) demonstrate higher intratumoral NK and T cell infiltration among exercisers
Clinical Applications and Implementation
The clinical implications are profound. Exercise should no longer be viewed as optional or “supportive care” but rather as a core therapeutic adjunct with measurable effects on recurrence and survival. Oncology programs are increasingly embedding supervised, behaviorally supported exercise interventions into treatment pathways—recognizing that adherence improves when programs provide guidance, monitoring, and motivational reinforcement.
Experts emphasize the need for structured, individualized exercise prescriptions: aerobic and resistance training that elevate heart rate and are tailored to the patient’s functional capacity and treatment status. Such programs are now being piloted across major cancer centers as part of integrative oncology services, with growing evidence that they represent a new standard of care
Clinical Significance
Exercise is redefining cancer therapy. By modulating metabolic, inflammatory, and immune pathways, it serves as a potent, low-cost, and accessible intervention capable of improving both quantity and quality of life. The evidence base now compels oncologists to prescribe exercise as deliberately as chemotherapy—transforming survivorship care from passive recovery to active, biologically engaged healing.
Source: https://www.scientificamerican.com/article/workouts-help-to-treat-cancer-and-improve-survival/
