Question: Does my race or ethnic background affect my risk of breast cancer?
Answer: To some extent, the answer to that is yes. Ethnicity is very clearly associated with several other factors and issues that can impact on breast cancer incidence and breast cancer outcome. Ethnicity can be associated with the genetics of breast cancer. Ethnicity is certainly associated with lifestyle issues, socio-economic issues, environmental exposures. And all of these different factors are associated when it comes to an individual person's risk of developing a breast cancer. And all of these factors are also associated when it comes to predicting an individual's likelihood of a good or a bad outcome for the breast cancer.
A couple of examples of these difficulties in evaluation would be with Ashkenazi Jewish women, where we know that there are certain genetic mutations that predispose women for being at risk for hereditary breast cancers, that some of these genetic mutations have a higher incidence among the Ashkenazi Jewish population.
Another example of where ethnicity is very closely associated with breast cancer risk and outcome is with the African-American population. It's been very clearly demonstrated in national population-based studies that overall, for women of all ages, breast cancer incidence, the numbers of breast cancers that develop, is actually lower among the African-American population compared to the Caucasian-American population. However, it's also been very clearly demonstrated that mortality, or death rate, from breast cancer is substantially higher for African-American women compared to Caucasian-American women. And it's very difficult to set out exactly why these disparate influences exist.
Again, there are very clearly socio-economic issues at play, since there are higher poverty rates among African-American women. And the socio-economic issues probably impact on access to medical care and delays in diagnosis. However, some of the other patterns that have been demonstrated are a little more difficult to explain. For example, African-American women are at greater risk for being diagnosed of breast cancer at younger ages. And, if you look specifically at women under the ages of 45, the incidence of breast cancer is actually higher for African-American women compared to Caucasian-American women. And this then raises the question of whether there might not be some genetic factors at play that are counting for the age distribution that we see for African-American breast cancer patients compared to Caucasian-American breast cancer patients.
And so the answer is clearly, yes, that ethnicity does affect likelihood of a breast cancer diagnosis and likelihood of surviving a breast cancer. However, we haven't clearly sorted out exactly why and how the ethnicity factors cause these influences.