Breast cancer and stress: the overlapping impact of mind and body

The relationship between stress and breast cancer has been widely studied, but remains complex. While current evidence does not confirm that stress directly causes breast cancer, researchers continue to explore how long-term psychological and biological stress might influence its development or progression, particularly through immune function, inflammation, and lifestyle changes.

This article outlines what we currently know about stress in its two forms - psychological and oxidative - and how both may interact with breast cancer biology. It also provides guidance on stress management practices that can support emotional and physical health throughout the cancer journey.

Does stress cause breast cancer?

Let’s start with the big question.

A comprehensive systematic review published in Clujul Medical in 2018 analyzed 52 studies conducted between 1966 and 2016, encompassing over 700,000 women and more than 29,000 breast cancer cases. The findings were mixed:

• 26 studies suggested a positive association between stress (including personal traits and stressful events) and breast cancer incidence.

• 18 studies found no significant association.

• 8 studies were inconclusive or could not be classified.

The review concluded that while there might be a possible link between stress and breast cancer, especially concerning stressful life events, the evidence is not definitive due to methodological differences among studies and the absence of a meta-analysis. 

However, the story doesn’t end there.

Many experts believe that chronic stress may still affect cancer indirectly, by:

• Increasing inflammation

• Weakening the immune system

• Worsening lifestyle factors (like poor diet, alcohol use, and physical inactivity)

In other words: while stress may not cause breast cancer, it can create the conditions where cancer is more likely to thrive or become harder to treat.

Understanding oxidative stress and its role

There’s another type of stress you don’t feel emotionally, but your body feels it hard: oxidative stress.

Oxidative stress happens when the balance between free radicals (unstable, damaging molecules) and antioxidants (protective molecules) is thrown off. This imbalance can:

• Damage DNA, proteins, and cells

• Lead to mutations that promote cancer

• Help tumors grow and spread faster

In breast cancer cells, oxidative stress is often higher than in healthy cells. This contributes to:

• More aggressive tumor behavior

• Increased resistance to chemotherapy

• Faster progression of the disease

The interaction between psychological and oxidative stress

These two types of stress aren’t the same, but they feed into each other.

• Psychological stress can worsen oxidative stress by increasing behaviors like smoking, drinking, or skipping meals.

• Oxidative stress can worsen psychological stress by increasing fatigue, inflammation, and the body’s vulnerability to illness.

Together, they create a cycle that impacts both the mind and the body, especially during cancer treatment.

Strategies for managing stress

There’s no one-size-fits-all approach to reducing stress, but even small shifts can make a big difference:

Lifestyle tips

• Eat a diet rich in antioxidants (berries, leafy greens, nuts, olive oil)

• Stay active with low-impact movement (walking, yoga, dancing)

• Reduce alcohol and avoid smoking

• Rest and sleep help the body reset and heal

Mental well-being

• Mindfulness and relaxation exercises

• Talk therapy or support groups

• Creative activities like art, music, or journaling

• Laughter, play, and connection (they work!)

Final thoughts

While research hasn’t established a direct link between stress and the development of breast cancer, it’s clear that stress affects how we feel, heal, and live, especially during and after a cancer diagnosis. Long-term stress can influence lifestyle, lower immunity, and make it harder to cope with treatment or recovery.

That’s why addressing stress isn't just a “nice to have.” It’s a meaningful part of caring for the whole person, not just the illness.

Whether it’s through quiet moments, nourishing food, gentle movement, or honest conversations, finding space to care for your emotional well-being is not a distraction from healing. It’s part of it. You deserve support that acknowledges every part of what you’re going through, physical and emotional, seen and unseen.