Age at diagnosis: 44
Just weeks after calling off her engagement to Lance Armstrong, the singer was diagnosed with an early stage of breast cancer in February 2006, later undergoing a lumpectomy and radiation treatment. "I've had so many people [say to] me, 'Gosh, you know, everything's really gone wrong for you this year,' and it took me going through that to realize that everything really went right for me," she said on The Oprah Winfrey Show. "It brought me to this point where I am now, and I really feel like I have a lot of clarity."