It may stand to reason that larger breasts place a woman at greater risk of breast cancer due to, well, the very size of them. At the very least, one might assume that finding a lump would be harder if you wear a triple-D cup compared to someone who wears, say, an A cup.
But is this a medical fact or just an urban myth?
Breast Size and Body Weight in Relation to Breast Cancer
The simple truth is that there have been no large, peer-reviewed studies that support breast size as a factor in the development of breast cancer. While there has been some research suggesting a link, there have been just as many which have drawn the opposite conclusion.
With that being said, we do know that obesity plays a significant role in the development of breast cancer and that obese women typically have larger breasts than the average woman. So while this might suggest that big-breasted women are at risk, it appears that weight is more of a factor than actual breast size.
Factors in Assessing Breast Cancer Risk
Beyond weight, there are key factors you should consider when assessing your personal breast cancer risk:
Family and Personal History
Having a mother, sister, or daughter with breast cancer doubles your risk right off the bat. Moreover, the risk only increases if your first-degree relative was young. If there are more than two such relatives, your risk triples and even quadruples.
But does that mean women with no familial history of cancer are free and clear? According to the American Cancer Society, that is not the case. In fact, between 70 percent to 80 percent of women diagnosed with breast cancer have absolutely no familial connection to breast cancer.
Women who drink alcohol increase their breast cancer risk. And the more a woman drinks, the higher the risk goes. In fact, research has shown that women who drink as little as two drink per day increase their risk by 15 percent when compared to women who consume no alcohol at all.
As an independent risk factor, alcohol is known to increase the levels of estrogen and other hormones associated with the development of breast cancer. Heavy alcohol use can also directly damage DNA in the cells of breast tissue. Damage like this can cause cells to multiply abnormally and at a heightened rate, giving rise to precancerous and cancerous tumors.
Genetic Risk Factors
Genetics may play a role in up to 10 percent of women diagnosed with breast cancer. This occurs when a mutated gene has been passed down from a parent, including the father. The most common mutations associated with breast cancer are BRCA1 and BRCA2.
If genetic esting indicates that a woman is a carrier of these mutated genes, she is at an increased risk for the development of breast cancer and will typically require more frequent monitoring than other women.
Women of Ashkenazi-Jewish heritage have between an eight and 10 percent risk of BRCA1-associated breast cancer, followed Hispanic women and Caucasian women. By contrast, African American women run a three percent risk of BRCA2-associated breast cancer.