What Is the Relationship Between Stress and Cancer?

Stress and cancer—although these two words often appear together, the link between the two is complex. While some studies suggest that people who are chronically stressed out have an increased risk for some types of cancer, there is no clear evidence that psychological stress actually causes any form of the disease. However, studies do indicate that living with stress may worsen existing cancer by promoting metastasis, or the spread of cancer throughout the body. That makes managing stress a key element of cancer self-care.  

The Nature of Stress 

Stress is the body’s reaction to difficult or challenging circumstances that everyone faces in life. Humans evolved in a way that causes us to release certain hormones that induce physical changes such as increased heart rate and faster breathing when we’re faced with a threat. This adaptation made our early ancestors better able to flee from or defend themselves against predators and enemies. This reaction, called the “fight-or-flight response,” is triggered when you perceive trouble and need to take action, such as when a vicious dog charges and you need to run away. However, the body also responds to perceived psychological threats by setting off the fight-or-flight response, which produces a flood of stress hormones that aren’t needed and may cause harm over the long term.  

There are two types of psychological stress: 

• Acute stress: Everyone experiences acute stress from time to time, which can be caused by the problems we all face in our daily lives, such as traffic, arguments with a friend or spouse, or difficulties at work. Acute stress can cause rapid heart rate, an increase in blood pressure, rapid breathing, muscle tension, and other symptoms, but the effects are temporary and don’t seem to increase the risk for disease. 

• Chronic stress: Feelings of anxiety and worry that persist over a long time cause chronic stress. Relationship problems with a spouse or partner, caring for a sick elderly parent, working at a job you don’t like, and money problems are all common causes of chronic stress. Chronic stress has been linked to heart disease, sleep disorders, high blood pressure, and other conditions. Importantly, chronic stress may lead to the release of excess cortisol, often called the “stress hormone,” which can suppress the immune system, the body’s defense network.  

Can Stress Cause Cancer? 

While chronic psychological stress is strongly associated with a number of diseases, the evidence that it causes cancer is mixed and not definitive, according to the National Cancer Institute (NCI). In some studies, researchers have found that people who report feeling high levels of stress had an increased risk for developing some forms of cancer, such as breast cancer, prostate cancer, and lung cancer. However, while these types of studies can demonstrate an association between stress and cancer, they do not prove that one causes the other. Moreover, several studies examining the connection between stress and cancer found no link between the two.  

However, the NCI points out that there could be an indirect link between stress and cancer. After all, many people respond to psychological stress by engaging in unhealthy behaviors such as smoking, drinking alcohol, and eating high-fat or high-sugar foods, which cause weight gain. All of these behaviors are associated with an increased risk of cancer.  

Stress And Cancer 

While the evidence that stress can cause cancer is in question, there are intriguing and important clues that experiencing persistent anxiety and worry can make cancer more likely to spread and harder to treat, notes the NCI. For example, in lab studies, mice with cancer progressed more rapidly (meaning their tumors grew and spread faster) if they were placed in isolation, which causes them to become highly stressed.  

Scientists have also determined that a hormone released in the fight-or-flight response called norepinephrine can cause tumors to grow and spread, or metastasize. Over time, living with chronic stress can cause other changes that encourage tumor growth. For example, some hormones released during stress promote increased blood supply to tumors, which helps them survive and grow. Others are capable of “turning off” the body’s natural defenses against cancer. Whether chronic stress decreases survival in cancer patients has not been proven, however.  

Dealing with Stress 

It’s understandable that anyone living with cancer might feel stressed and anxious, but managing those feelings will improve your quality of life, and just might contribute to better control of the disease. Experts recommend the following strategies: 

• Share your feelings: Don’t be tempted to hide your feelings about living with cancer from family and friends. Be open about the emotions you are experiencing—keeping them “bottled up” only worsens feelings of stress.  
• Seek support: Family and friends are important sources of solace and comfort, but joining a support group for people who have your type of cancer can bring you in close, regular contact with others who understand your experience and can share advice about coping with the disease. Ask your healthcare team if they can recommend a support group or simply use a search engine to locate one in your community.  
• Consider psychological counseling: Some psychotherapists and licensed social workers specialize in working with people who are coping with stress related to living with cancer and other diseases. Stress often leads to depression, which can also be addressed in psychotherapy. If necessary, antidepressants or anti-anxiety medications may be prescribed by a doctor as necessary. 
• Get some exercise: Physical activity releases “feel good” hormones called endorphins, which can help counteract feelings of stress and depression. Living with cancer may place limits on how much you can exercise, so talk to your doctor about a plan that makes sense for you.  
• Eat healthy: A diet rich in fruit, vegetables, and whole grains can help strengthen the immune system; avoid the temptation to “self-medicate” stress by eating junk food, abusing alcohol, and smoking.  
• Meditate: A powerful tool against stress, meditation can help slow down racing thoughts and calm the mind. There’s nothing mysterious or exotic about meditation, as many believe. You may find a class at your local community center or hospital, or you can try different types of meditation on YouTube. Meditation also lowers blood pressure and improves sleep quality.  
• Try biofeedback: There are many types of biofeedback systems and devices, which use electrical sensors to monitor your heart rate and other vital signs. This information is conveyed back to you on a screen or by other means, which helps you learn to modify it through relaxing tense muscles or slowing down your breathing, for example.  

Source: MD Anderson Cancer Center, National Cancer Institute