"Technically, I was cancer-free after the lumpectomy in March, but then I had radiation to make sure that it killed any cancer cells that were still hovering about," she says.
The 53-year-old was diagnosed in February with ductal carcinoma in situ (DCIS), a non-invasive form of breast cancer.
"Surgery was easy," she says, "but the radiation was trickier. It was six weeks of really low energy. Radiation just sucks your energy like a vampire, day by day."
Navratilova says that she now feels "as good as new" and has an excellent prognosis. She's resumed playing tennis and even wants to try some extreme sports.
"I want to start surfing," she says. "I snowboard, so I'm sure I can learn to surf. It will happen someday. I've got the rest of my life to learn."