Medical Informations

Medical Informative Booklets

Medical Imagery

Your Questions about Breast Cancer Screening, Diagnosis, and Local Follow-up
The Risk Factors of Breast Cancer

What are the factors that increase the risk of developing breast cancer ?

Breast cancer does not result from only one cause but from the successive and cumulative action of several factors.
In other words, breast cancer's origin is "multifactorial". The family background (heredity, genetic factors) may play a part in making women more sensitive to the exposure to other factors. The association of "minor risk factors" with the family background may be responsible for the development of cancerous cells. It is important to say that the family background makes people more sensitive (vulnerable) to carcinogenic agents but not to cancer in itself.

• In certain kinds of breast cancer, the hormonal state, and especially the exposure to oestrogens, is a significant risk factor in case of, for instance :
  - a long period of genital life due to early menarche (first period) and late menopause.
  - a first pregnancy at a late age (considered to be late after 35 years old)
  - an absence of breast-feeding
  - obesity and alcohol consumption that may cause an overproduction of oestrogens.
  - a replacement hormones treatment after menopause.
• However, the contraceptive pill does not seem to increase the risk of having breast cancer.
• Belonging to a family in which some members had breast cancer also has an impact : A woman whose parents had breast cancer is three times more likely to have cancer than any other woman. The more a breast cancer breaks out early, the more the risk is important. If cancer was bilateral, the risk of having breast cancer rises even more.
  If the patient has undergone a biopsy because she had an injury which was still harmless but which was precancerous, and also because she had an atypical epithelial hyperplasia, she is more likely to have breast cancer too

Can I do something to decrease the risk of developing breast cancer ?

No, for the moment, any study managed to show that lifestyle has an effect on the risk of developing breast cancer. Nevertheless, a combination of risks that are said to be "minor" may cause a cancerous growth, especially when people have a particular family background.

• Diet : it seems that there is a relation (but it is not formally accepted) between the consumption of saturated animal fats (butter, fat meat) and the increased risk of having breast cancer. Breast cancer is 5 to 7 times less likely to appear in Asia (Japan) where people eat more fish and vegetables and less meat. If Asian women migrate to the United States (for instance), they catch up with American women in terms of number of breast cancer, within the space of one generation. It is advised to eat food that is rich in vitamin A, E and C (fruits and vegetables) and also vegetable fibres that improve digestion and would thus reduce the duration of contact between the intestinal mucous membrane and carcinogenic food. It is better to avoid eating salty or smoked food because it contains nitrite that also produces carcinogenic substances.
• Tobacco and alcohol were also accused by some studies.
• The effect of exposure to chemical pollution which is in the air, in the water and in the food was also accused.
• On the other hand, doing sport (3 to 4 hours per week) could reduce the risk of having breast cancer.

Does stress play a part in triggering breast cancer ?

It was never proved that stress, emotional shock or depressive state may further cancer development. However, like for any other disease, a positive state of mind and the strong will to recover play a significant part.

 

What about family or genetic factors ?

A family background characterised by breast cancer is one of the "major" risk factors of having breast cancer (that does not mean that people who do not have a family member suffering from cancer won't have breast cancer).
About 4 to 10% of the population presents a "strong hereditary predisposition"; in their case, the risk of developing breast cancer is extremely high (up to 80% during lifetime). This heredity is due to a gene abnormality called "autosomal dominant " (BRCA1, BRCA2). This gene may be of maternal or paternal origin.
Half of breast cancers break out before the age of 40 in women who are genetically predisposed, and in this case cancers are bilateral most of the time.

In about 15% of other cases, people are more likely to develop breast cancer because they have some weak genes and there is an association of "minor risks". The presence of breast cancer in a family does not necessarily cause underlying genetic predisposition but may be due to a fortuitous series of cases (by accident).

It is very hard to spot high-risk people in families where women are few, especially when genetic predisposition is transmitted by the paternal lineage. For a woman, the risk of developing breast cancer is mulitplied by 1.5 to 3 if her mother, her daughter or her sister is suffering from this disease, but the risk increases even more if the family related is young when she is diagnosed or if the cancer is bilateral (risk factor from 1.5 to 9).

Back to : Choice of "Medical Informative Booklets"