“Can Stress Cause Breast Cancer?” – What Researchers Really Say

October, the international Breast Cancer Awareness Month, is a reminder that this disease affects not only the body, but also the mind, the heart, and the inner life. More and more studies are exploring the link between mental health and breast cancer — both before and after diagnosis. But what do we really know? And what remains to be understood?

Before Cancer: Is Mental Health a Risk Factor?

For several years, researchers have wondered whether depression, anxiety, or chronic stress might influence the risk of developing breast cancer.Some studies — such as a large genetic analysis published in BMC Medicine in 2023 — have observed a slight association between depression and an increased risk of breast cancer, by about 12%. Other case-control studies have suggested that major life events (bereavement, separation, intense work-related stress) could be linked to a higher risk.

However, researchers emphasize:

These links remain weak and do not prove a cause-and-effect relationship.

Stress or depression do not cause cancer.They may, however, influence hormonal mechanisms (such as cortisol), immunity, sleep, or behaviors (tobacco, alcohol, diet), which themselves can affect overall risk.

Results vary widely depending on the population studied, how stress is measured, and lifestyle factors. It is therefore important to interpret these findings with caution: mental health is not a “major risk factor”, but rather part of a broader physiological and psychological balance.

During and After Cancer: Healing the Mind, Too

Once the diagnosis is made, mental health becomes an essential part of treatment. Between 30 and 40% of women with breast cancer experience depressive or anxious symptoms, especially in the months following surgery or during hormonal therapy. These reactions are understandable: fear of recurrence, changes in the body, fatigue, and loss of identity deeply affect one’s sense of self and quality of life.

Several studies have shown that patients receiving regular psychological support — individual or group — cope better with treatments and are more likely to adhere to medical follow-up. Some research even suggests that untreated depression could negatively affect recovery, immune response, and, in some cases, overall prognosis.

Beyond the numbers, mental health is a pillar of healing.Recovering from breast cancer also means learning to trust one’s body again, to rediscover pleasure, meaning, and connection. Psychological work, active listening, therapy, meditation, spirituality, or art therapy can all help restore that inner dialogue broken by illness.

In Summary

• Mental health is not a direct cause of breast cancer, but a key part of overall well-being.

• Stress, anxiety, and depression can influence biological mechanisms related to the disease.

• After diagnosis, psychological support is as essential as medical treatment.

• Taking care of your mind means taking care of your health.

  
  

Take good care of yourself!

Warm regards,

Dr. Sandra Yene Amougui