Links of Chronic Stress and Cancer

Recent studies have shown the critical link between stress and cancer through the impact of the immune system. It has been shown that chronic stress suppresses immune surveillance, reducing the body’s ability to detect and eliminate unhealthy or foreign cells.  

Due to chronic stress, some key roles provided by the immune system cells are either suppressed or defeated. Chronic stress has been shown to directly impact the immune system defenses by increasing glucocorticoid signaling, which downregulates immune cell pathways responsible for identifying and destroying abnormal cells.  Due to chronic stress, we see a decrease in natural killer (NK) cell activity, T-lymphocytes, and macrophage functions. This decrease in cell activity impairs the coordination between innate and adaptive immunity, leading to the reduced ability to detect and destroy abnormal or tumor cells. This impaired response from the cells also decreases wound healing and increases the susceptibility to infectious diseases, viruses, and cancer. _(A) However, these mechanisms may vary depending on the duration and severity of the stress exposure. 

In addition to these effects, prolonged stress exposure has also been shown to increase glucocorticoid resistance. This allows the immune system cells to become less responsive to cortisol, and as a result, lose the proper immune regulation and promote inflammation in the body._(B)  The combination of weakened immune function and impairment leads to a greater risk of infection, healing, and chronic diseases, such as cancer. This reduction in immune surveillance is significant because early tumor cells are normally identified and eliminated by the NK cells before they can proliferate. When this system is weakened, abnormal cells may persist longer, increasing the likelihood of tumor progression. This suggests that immune dysfunction is not isolated but part of a systemic stress response affecting tumor surveillance.

Functional medicine can play a key role in cancer prevention in many different areas. One way is through restoring the immune surveillance system of the NK and T-lymphocytes. Functional medicine approaches this through a mind-body connection by reducing stress load, both behavioral and physiological. By stress reduction management and therapies, the body can reduce the response and overtime may support restoration of homeostasis.  Functional medicine can also play a role in supporting the immune system through nutrition, such as, balancing micronutrients like zinc, vitamin C, and vitamin D. By reducing external stressors and increasing important key nutrients, this will improve sleep and essentially help improve the immune cells and NK activity. 

While evidence supports a link between chronic stress and immune suppression, it is important to note that cancer development is multifactorial and can not be attributed to stress alone.

References:

_(A)Author(s) unspecified. Regulation of stress-induced immunosuppression in the context of neuroendocrine, cytokine, and cellular processes. [Internet]. 2024. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11760489/ 

_(B) Author(s) unspecified. Chronic stress and autoimmunity: the role of HPA axis and cortisol dysregulation. [Internet]. 2025. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC12563903/