The truth is that we often can’t say what caused a person to develop breast cancer.  We do know a few risk factors that are known to be associated with developing breast cancer.  Here is a short list below.

Gender.  Breast cancer is about 100 times more common in women than in men.

Age.  Risk increases with advancing age.  In fact, breast cancer is much more common from 50-60 and above, compared to less than 40 years of age.

Ethnicity/race.  We know that breast cancer after menopause is more common among white women.  Nonetheless, it is worthy of mention that women of African and African-American descent are disproportionately affected at less than 45 years of age, and with a potentially aggressive type called triple negative breast cancer.

Estrogen exposure.  Women who take hormone replacement at menopause may be at slightly higher risk for breast cancer.  Also, women who have early menarche (first menstrual period) and late menopause (last menstrual period) and who did not have pregnancies or few pregnancies, may be at higher risk.  Women who had pregnancies later in life and/or did not breastfeed at all or not for long, may also be at higher risk.  In other words, breast cancer risk increases with years of uninterrupted estrogen exposure.

Family history.  There are likely many reasons why family history is a risk factor, some of it related to genetics.  Look out for a future article specifically looking at genetics and breast cancer risk.  Breast cancer risk is particularly related to number of first degree female relatives already with a diagnosis.

Social habits and work.  Both alcohol and smoking may increase breast cancer risk.  It is also well recognized that night shift work in women, does have an association with breast cancer risk.

Height.  Surprising perhaps but yes, women above 175 cm (or 69 inches) had  higher risk of breast cancer than shorter women in a study.

Breast structure and disease.  Women who have a history of dense breasts (this is seen on mammograms, rather than felt) have a higher risk of breast cancer and also, if cancer develops, it may be harder to see on conventional 2D mammograms particularly.  A history of non-cancerous breast disease, particularly if the cells had abnormal features (aka atypia) is also another breast cancer risk factor.

Past treatments:  Prior radiation to the chest wall is risk factor for breast cancer.  Individuals who had (mantle) radiation for lymphoma in their younger years may fall in this category.

Are there any other thoughts you have?  Please feel free to leave a comment below.