Does stress cause breast cancer?

There is a widespread public belief that stress can lead to cancer and especially to breast cancer.

Over the last twenty years there have been many scientific studies looking at whether there really is a relationship between stress and cancer. These studies have used a number of different methods. Many have looked at women with benign and malignant (cancerous) breast lumps and compared the number of major stressful events in the five years or so before their condition was diagnosed, to see if the women with cancers had suffered more stress. Others have followed the lives of people who have been bereaved, or who were prisoners of war, to see if these stresses led to a greater chance of cancer developing in the future when compared to the normal population.

When the results of all these studies are analysed there is absolutely no evidence that stress does cause cancer. Since more studies have been done on breast cancer than any other type of tumour it does seem very certain that there is no link between stress and getting cancer of the breast.

At the end of the day stressful life events - bereavement, divorce, redundancy, moving house and so on are very common and inevitably many women who do develop a breast cancer will have experienced one or more of these in the few years before their tumour was discovered. We don't really understand why breast cancers develop and so people often think stress is a very believable explanation but there is no scientific evidence to suggest that these stressful life-events are any commoner for breast cancer patients than for the population at large.