By Archana Ram
Updated April 07, 2010 at 04:59 PM EDT

Tennis legend Martina Navratilova announced this morning on ABC’s Good Morning America that she has been diagnosed with breast cancer. Navratilova, who called the diagnosis her “personal 9/11,” was treated for an aggressive form of ductal carcinoma in situ (DCIS), which is considered the earliest form of breast cancer, and had a lumpectomy in February. She said there is a “very small chance” of the cancer returning.