Does stress cause cancer?

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The claim

When you live with a lot of stress, you’re at a greater risk for developing cancer.
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The truth

Research has not proven a definite cause-and-effect relationship between stress and cancer. The connection between your emotional (psychological) health and physical health is very complex. Psychological stress can affect your body. Some studies suggest a link between various psychological factors and an increased risk of developing cancer.

3 cancer risk factors linked to stress

  • Stress can weaken your immune system. Your immune system defends your body against infections and diseases, such as cancer. A weakened immune system plays a role in the development of some types of cancer.
  • Stress can alter the levels of certain hormones in your body. This may also put you at greater risk of developing cancer.
  • Stress may lead to unhealthy behaviours. Overeating, smoking and heavy drinking are all lifestyle factors that increase cancer risk.

The Canadian Cancer Society is committed to sharing important information about cancer risk to Canadians and will continue to monitor research in this area.