Advancing age is a risk factor for breast cancer. In fact, more than half of the cases diagnosed occur in women who are 60 or 65 years or more. As per statistics of American cancer society, every  one out of 8 invasive breast cancers develops in women less than 45 years of age. Every 2 out of 3 invasive breast cancers occur in women 55 years of age or older.  As one ages, she is more exposed to estrogens, particularly if menopause has been late. Living older also allows greater  genetic mutations to occur in the cells . The repair of damaged body cells becomes less with advancing age. Damage to body cells by free oxygen radicals becomes a risk factor for cancers including breast cancer. Alcohol and tobacco use are other risk factors for breast cancer. The damage to body cells and risk increases with age. It adds on the risk of having breast cancer with advancing age.