updated 04/07/2010 AT 9:35 AM ET
•originally published 04/07/2010 AT 12:00 PM ET
Tennis legend Martina Navratilova has been diagnosed with breast cancer. The disease was detected early, and the prognosis is said to be excellent.
“I cried,” Navratilova, 53, tells PEOPLE about the moment in February when a biopsy came back positive after a routine mammogram revealed a cluster in her left breast. “It knocked me on my ass, really. I feel so in control of my life and my body, and then this comes, and it’s completely out of my hands.”
She was diagnosed with a non-invasive form of breast cancer called ductal carcinoma in situ, or DCIS, which in her case was confined to the milk ducts and had not spread to the breast tissue. “It was the best-case scenario you could imagine for detecting breast cancer,” Dr. Mindy Nagle, a good friend of Navratilova’s (and her ob gyn), tells PEOPLE.