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Myth: The size of a woman’s breasts affects her risk of breast cancer.

By Rethink Breast Cancer September 14 2017

Having large breasts or small breasts does not affect your risk for developing breast cancer. Breast cancer develops in the cells that line ducts or lobules. Women of all breast sizes have the same amount of these. A woman’s breasts are large due to the presence of more fatty, or fibrous, tissue – which has little to do with cancer.

What’s more important is breast density, when breasts have greater amounts of connective and milk duct tissues, because this is where most breast cancers form. This is the only physical breast characteristic proven to increase breast cancer risk. Women with more than 75% dense breast tissue have a risk four to six times greater of breast cancer than other women. It is much harder to detect breast cancer in dense breasts using a mammogram because the tissue looks white, like tumours. There is also no link between breast size and breast density. In most cases, it is a genetic characteristic that is inherited.

For more information on how to find out if you have high breast density, click HERE.

While it’s important that we are doing what we can to reduce our risk by being physically active and making healthy dietary choices, it’s also important that we are keeping complicated issues and information from being misinterpreted and spread as rumours.

A lot of studies have stated that larger breasted women are more likely to develop breast cancer, contributing to this myth. However, most often these studies come to this conclusion because larger breasted women are more likely to be larger in weight or size and having a high Body Mass Index (BMI) – an indicator of body fatness – has been proven to increase breast cancer risk. A lack of physical activity is a factor that increases a person’s risk of developing breast cancer. So, regardless of breast size, if you are a healthy, active person you are already taking the steps necessary to reduce your risk.

Get more breast cancer facts