From iVillage Health:
In the 1940s, a woman’s lifetime risk of breast cancer was one in 22. Today, her risk has risen to one in eight. This is mainly due to the fact that women are living longer, as breast cancer is a disease whose likelihood increases with age, explains Michael Roizen, MD, chief wellness officer at the Cleveland Clinic. While nothing can prevent breast cancer completely, these 16 habits can help.16 Ways to Lower Your Risk of Breast Cancer 
Are you practicing any of them already?