Can Stress Cause Cancer?

A wide-scale meta-analysis – a study of studies – by psychobiologists at University College London looked at the link between stress and cancer. Researchers reviewed 168 studies and examined the effects of stressful events like death, divorce and work, as well as individual reactions to these events. They found that people with "stress-prone personalities, unfavorable coping styles and negative emotional responses" had an increased risk of developing cancer and, in individuals already diagnosed with cancer, lower rates of survival. Increased incidence was specifically associated with cancers of the breast, lung, head, neck, liver, lymph and blood.

Stress is unavoidable. In the short-term, some can be good for us, like preparing to run a race or give an important presentation. But chronic, unmanaged stress can be dangerous. Stress hormones that activate the body's sympathetic nervous system responsible for "fight or flight" reactions (like increased heart rate, higher blood pressure and muscle contractions) also inactivate non-necessary functions like digestion and immune surveillance. Natural killer cells responsible for detecting and destroying cancerous or precancerous cells become less active when blood levels of stress hormones cortisol and noradrenaline are high. This facilitates the growth and spread of tumors.

Studies at the National Cancer Institute have shown that in women diagnosed with breast cancer, the more positive their psychosocial outlook, the more active their natural killer cells. And the more active their natural killer cells, the higher their chance of long-term survival. Conversely, women who were distressed, depressed, and/or lacking social support had less active natural killer cells, not just in their blood but at the tumor level as well. Their tumors were also more likely to spread to nearby lymph nodes and rates of cancer recurrence were higher.

These studies highlight the importance of managing stress, finding joy, connecting with others and cultivating emotional and spiritual health, whether you have been diagnosed with cancer or seek to prevent it.

References: 

Chida Y et al. Do stress-related psychosocial factors contribute to cancer incidence and survival? Nature Clinical Practice, Oncology, 5(8):466-75, August 2008.

Levy S et al. Correlation of stress factors with sustained depression of natural killer cell activity and predicted prognosis in patients with breast cancer. Journal of Clinical Oncology. 5(3):348-53, March 1987.

Levy SM et al. Immunological and psychosocial predictors of disease recurrence in patients with early-stage breast cancer. Behavioral Medicine, 17(2):67-75, Summer 1991.

Levy SM et al. Prognostic risk assessment in primary breast cancer by behavioral and immunological parameters. Health Psychology, 4(2):99-113, 1985.

Lutgendorf SK et al. Social support, psychological distress, and natural killer cell activity in ovarian cancer. Journal of Clinical Oncology. 23(28):7105-13, 1 October 2005.