Most breast cancers are diagnosed in women with no family history of the disease and new data shows many women are aware of lifestyle changes that could lower their risk but are not making them.

The American Cancer Society estimates more than 30 percent of breast cancers are considered preventable through certain healthy choices.

"About 85 percent of breast cancers are actually diagnosed among women who don't have a family history," Alpa Patel with the American Cancer Society said. 

The new data found that awareness does not always translate into action. "About 9 out of 10 women surveyed knew that physical activity was important to lowering their cancer risk, but only about 27 percent of the population actually was meeting the American Cancer Society guidelines," Patel said.

The American Cancer Society recommends 150 to 300 minutes of moderate-intensity activity like a brisk walk or 75 to 150 minutes of vigorous activity like running, every week to support health and reduce cancer risk.

Alcohol use also raises breast cancer risk and a majority of women surveyed reported drinking to some extent.

The least-known protective factor, according to the organization, is breastfeeding. Only about half of women surveyed knew it can help lower cancer risk.

A free online tool called ACS Cancer Risk 360 is available to help women understand their personal risk level. "It's a great tool. To really have an understanding about what your risk level is and where there are opportunities to lower that risk," Patel said.