Navratilova said she has a noninvasive form of the cancer, called ductal carcinoma in situ, that was detected during a mammogram.

CNN: Martina Navratilova has breast cancer

Days after the 2004 election, in which her husband ran for vice president, Elizabeth Edwards was found to have invasive ductal carcinoma, the most common type of breast cancer.

CNN: Edwards: Cancer 'no longer curable'

Even in the precancerous stage, called ductal carcinoma in situ (DCIS) when abnormal cells are confined to a milk duct, physicians almost always advise women to have a lumpectomy or mastectomy along with radiation, because about 20% of the 65, 000 cases of DCIS found every year in the U.S. become invasive cancer.

WSJ: Can Breast Cancer Be Overtreated?