Why Your Body Can’t Heal While You Are Stressed: Link Between Stress and Cancer

Psychological stress weakens the immune system - the body’s main line of defence against cancer - and disrupts almost all our body’s processes. However, we can’t completely eliminate stressors from our life and need to be able to live with stress but not with its consequences. Thanks to numerous studies on the mechanisms of stress, we now know that the solution is not to stop stressful life events from happening to us, but to manage our response to them.

In this article:

• What is Stress?

• 3 Types of Stress

• Link Between Nervous System and Immune Function

• Does Stress Cause Chronic Illness?

• Stress and Cancer

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What is Stress?

Stress can be described as a response to excessive demands made on an organism, a disruption in the constancy of our internal milieu (homeostasis), while a stressor represents an absence, real or threatened, of something that we believe to be necessary for our survival.[i]

Stress is part of our everyday life, and not always a bad thing.

Positive stress, or eustress, is the enjoyable type of stress response that produces positive feelings of excitement, satisfaction, and well-being. It can also refer to the times when we respond well to a life event or a challenge. In other words, eustress is experiencing a challenge outside our comfort zone and coping well with it. An example of positive stress can be getting a promotion, going on a first date or buying a home. The founder of stress research Dr Hans Selye referred to stress as the spice of life.

Eustress is always short-term, unlike distress, or negative stress, which can also be caused by long lasting stressors.

Biologically, a short-term acute stress is a release of hormones resulting in a fight-or-flight response, a mechanism which we have developed to rapidly respond to threats and defend ourselves over thousands of years of human evolution.

However, chronic stress – prolonged stress that does not go away when the threat is no longer present – is not adaptive. The same stress responses, repeatedly activated but inhibited and not followed up by actions like fight or flight, cause damage to the overall health. Such chronic stress impairs the immune system in a way that makes it impossible for it to function as a defensive mechanism.

3 Types of Stress

What specifically does the body perceive as stress that prevents the immune system from functioning properly?

Stress comes in different forms.

Physical stress can be due to the lack of sleep, injuries, traumas, bad posture and issues associated with the sedentary lifestyle.

Biochemical stress, which refers to an imbalance of chemicals in the body, can be caused by diet, smoking, excessive alcohol intake, medications, as well as by hazardous substances in the air we breathe or the products we use.

Emotional (or mental) stress represents the gap between our coping abilities and psychological demands that our life makes on us, which is expressed as anxiety, fear, resentment, being overwhelmed, feeling out of control, and so on.

Chronic stress has been linked to almost every major disease. Disorders generally recognized as stress-related include obesity, heart disease, arthritis, Alzheimer's disease, diabetes, insomnia, depression, cirrhosis of the liver, digestive problems, asthma, chronic fatigue, allergies, and cancer.[ii],[iii] It is estimated that between 75 and 90% of all doctor’s office visits are for stress-related ailments and complaints.[iv]

In his book “When the Body Says No: The Cost of Hidden Stress”, Dr Gabor Maté, a medical doctor renowned for his research on the relationship between stress and illness, identifies three sources of stress: uncertainty, lack of information and loss of control. According to him, chronic illness patients live with all the three factors constantly present in their lives.

Link Between Nervous System and Immune Function

Our bodies can only operate in one of the two modes at a time: rest-and-digest or fight-or-flight mode. It is the nervous system that “decides” which mode is better suited for us at a particular time.

The capability of the nervous system to enable or block healing depending on its state is clearly illustrated by cancer. It is universally acknowledged that cancer is the result of acquired or germline mutations in a living cell.[v] Mutations occur in our cells constantly, but the immune system is able to seek them out and repair them, provided that the body spends enough time in the rest-and-digest mode for the immune system to do its work.

The body has its own powerful natural defences to stop cancer from developing. They include:[vi]

• white blood cells, including natural killer (NK) cells to specifically target tumour cells;

• apoptosis, the process of programmed cell self-destruction that rids the body of damaged cells before they can divide;

• antibodies (proteins), for detecting antigens (invaders such as cancer cells) for the body to destroy.

When the immune system is weakened by stress, white blood cells do not kill cancer cells, the mutated cells do not die as programmed but multiply, and antibodies do not bind to antigens.

Does Stress Cause Chronic Illness?

Our mind does not know the difference between real and imaginary threats which trigger the survival response. Thus, our response to negative life events is determined not by the objective severity of those events, but by how severe they seem to us personally.

An interesting study was undertaken in 1967 in the USA by psychiatrists Thomas Holmes and Richard Rahe who analysed data from more than 5,000 patients to establish if there was a link between stress and illness. As a result of this work, they developed a rating scale as an attempt to measure the amount of stress at a particular time in a person’s life.[vii]

Life event	Life change units
Death of a spouse	100
Divorce	73
Marital separation	65
Imprisonment	63
Death of a close family member	63
Personal injury or illness	53
Marriage	50
Dismissal from work	47
Marital reconciliation	45
Retirement	45
Change in health of family member	44
Pregnancy	40
Sexual difficulties	39
Gain a new family member	39
Business readjustment	39
Change in financial state	38
Death of a close friend	37
Change to different line of work	36
Change in frequency of arguments	35
Major mortgage	32
Foreclosure of mortgage or loan	30
Change in responsibilities at work	29
Child leaving home	29
Trouble with in-laws	29
Outstanding personal achievement	28
Spouse starts or stops work	26
Beginning or end of school	26
Change in living conditions	25
Revision of personal habits	24
Trouble with boss	23
Change in working hours or conditions	20
Change in residence	20
Change in schools	20
Change in recreation	19
Change in church activities	19
Change in social activities	18
Minor mortgage or loan	17
Change in sleeping habits	16
Change in number of family reunions	15
Change in eating habits	15
Vacation	13
Major Holiday	12
Minor violation of law	11

Holmes and his team noticed that they were able to predict the probability of illness based solely on the accumulated number of points from this scale. However, 51% of the people with the highest point scores did not develop an illness within 12 months, despite being exposed to the same amount of stress as those who did. To put it another way, while stress contributes to illness, what matters is not how much stress a person has experienced but how he or she responds to it. And managing our response to stress is under our control.

It is our ability to cope with the demands made by the events in our lives, not the quality or intensity of the events, that counts.

– “The stress of Life”, Dr Hans Selye

Another research paper[viii] suggests that factors which moderate the effect of stressors on stress response are personality traits, coping styles, past experience with the stressor, and perceived self-efficacy.

How we cope with a stressful event depends on the meaning that we attribute to it, meaning that might change over time. The mind doesn’t simply react to life events but interprets and re-interprets them based on our past experiences, beliefs and expectations. By choosing our beliefs and managing our expectations, we can influence the process of forming those meanings.

Dr Hans Selye pointed out that it is not the external stressor but “how you take it” that determines whether one can adapt to change successfully.[ix] “Many diseases are actually not so much the direct results of some external agent (an infection, an intoxication) as they are consequences of the body’s inability to meet these agents by adequate adaptive reactions.”

Stress and Cancer

Large bodies of evidence indicate that chronic stress has a role to play in the causation of cancer, tumour growth rate and metastasis.[x],[xi],[xii]

In addition to inhibiting the body’s immune system, chronic stress:

1. Induces inflammation. Excessive inflammation plays critical roles in the progression, and/or onset of stress-related diseases such as cancer.[x]

2. Causes the release of stress hormones which promote tumour growth,[xiii] and

3. Activates the sympathetic state of the nervous system where the body doesn’t heal or recover.

The development of cancer does not require just the presence of abnormal cells, it also requires a suppression of the body’s normal defences.

– “Getting Well Again”, Dr Carl Simonton

In conclusion, stress has major consequences for overall health and is known to contribute to cancer. However, it is not external stressful life events that create susceptibility to cancer but our emotional response to them. That is how we could prevent the occurrence or development of tumours by taking care of our emotional health, in particular, by managing stress, learning about emotion-based coping skills and building resilience.

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References

[i] Maté G. (2019). When the body says no: the cost of hidden stress. Vermilion. [ii] Dispenza, J. (2014) You Are the Placebo: Making Your Mind Matter. Hay House Inc. [iii] Salleh M. R. (2008). Life event, stress and illness. The Malaysian journal of medical sciences : MJMS, 15(4), 9–18. [iv] WebMD LLC. https://www.webmd.com/balance/stress-management/effects-of-stress-on-your-body [v] The Genetics of Cancer https://www.cancer.net/navigating-cancer-care/cancer-basics/genetics/genetics-cancer [vi] Cancer Research Institute https://www.cancerresearch.org/blog/april-2019/how-does-the-immune-system-work-cancer [vii] Holmes, T. H. and Rahe, R. H. (1967) The social readjustment rating scale. Journal of Psychosomatic research, 11(2), 213-21. [viii] Thornton, L. M., & Andersen, B. L. (2006). Psychoneuroimmunology examined: The role of subjective stress. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2473865/

[ix] Selye H. (1978). The stress of life (Rev.). McGraw-Hill. [x] Liu, Y. Z., Wang, Y. X., & Jiang, C. L. (2017). Inflammation: The Common Pathway of Stress-Related Diseases. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5476783/ [xi] Thaker, P. H., Han, L. Y., Kamat, A. A., Arevalo, J. M., Takahashi, R., Lu, C., Jennings, N. B., Armaiz-Pena, G., Bankson, J. A., Ravoori, M., Merritt, W. M., Lin, Y. G., Mangala, L. S., Kim, T. J., Coleman, R. L., Landen, C. N., Li, Y., Felix, E., Sanguino, A. M., Newman, R. A., … Sood, A. K. (2006). Chronic stress promotes tumor growth and angiogenesis in a mouse model of ovarian carcinoma. https://pubmed.ncbi.nlm.nih.gov/16862152/ [xii] Hong, H., Ji, M., & Lai, D. (2021). Chronic Stress Effects on Tumor: Pathway and Mechanism. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8720973/ [xiii] Liu, Y., Tian, Sh., Ning, B., Huang, T., Li, Y., Wei, Y. (2022) The mechanisms of immune dysregulation and management; https://www.frontiersin.org/articles/10.3389/fimmu.2022.1032294/full