Does Breast Size Affect Breast Cancer?

Different sized oranges

The thought that having small breasts reduces your risk of breast cancer is just one of many breast cancer myths circulating email inboxes and water cooler chats. There are no large, peer-reviewed studies that support breast size being a factor in breast cancer development.

We do know that obesity is a risk factor for breast cancer and, typically, obese women have larger breasts than women at a healthy weight.

This may have been one of the factors that incorrectly fueled this myth. While breast size may not influence your breast cancer risk, there are several things that do.

Family & Personal History

Having a mother, sister, or daughter with breast cancer doubles your risk of the disease. While family history can play a role in breast cancer development, women shouldn't subscribe to the popular belief that women without a family history of breast cancer aren't at risk. The American Cancer Society estimates that 70 percent to 80 percent of women with breast cancer do not have a family history that includes breast cancer.

Alcohol Consumption

Women who drink alcohol increase their breast cancer risk and the risk is heightened with the amount of alcohol consumed. Women who drink two to five drinks a day increase their risk by one and a half times when compared to women who do not drink alcohol. One drink a day only slightly elevates a woman's risk.


Genetics may play a role in up to 10 percent of women diagnosed with breast cancer. Hereditary breast cancer occurs when a mutated gene has been passed down from a parent. The most common genetic mutation is that of the BRCA gene pair, referred to as "BRCA1" and "BRCA2."

These genes are responsible for regulating cell growth and repairing damaged DNA but do not properly function if mutated.

Those who are found through genetic testing to be carriers of mutated BRCA genes are at an increased risk of developing breast cancer.

Other gene types have been associated with breast cancer, but not as prevalently as the BRCA genes. It is important to note that mutated BRCA genes can be passed down from fathers, not just mothers—one of the more popular breast cancer myths.

Continue Reading