According to the American Cancer Society, about 1 in 8 (12%) women in the US will develop invasive breast cancer during their lifetime. Here are the American Cancer Society's most recent estimates for breast cancer in the United States for 2012: About 226,870 new cases of invasive breast cancer will be diagnosed in women. About 63,300 new cases of carcinoma in situ (CIS) will be diagnosed (CIS is non-invasive and is the earliest form of breast cancer). About 39,510 women will die from breast cancer. As part of National Breast Cancer Awareness Month, October 19 is National Mammography Day. In 1993, President Clinton first proclaimed that the third Friday in October would be deemed National Mammography Day. Women are encouraged to make an appointment for a mammography on this day or throughout the month of October.