According to the site, Crow's doctors call her prognosis "excellent"; she will receive radiation therapy treatment as a precaution.

In a statement released to PEOPLE today, Crow's former fiancé, Lance Armstrong, said, "I was devastated to hear this news. Once again I'm reminded of just how pervasive this illness is as it has now touched someone I love deeply." 　　

The cycling champion continued, "Based on my contact in recent days with Sheryl, her doctor, and her family, I am confident that she will have a full and complete recovery and the world will be a better place for it. And to all of her fans and friends out there, please keep Sheryl in your thoughts and prayers yet know that I have never known a stronger woman in my life."

Early this month, Crow, 43, and Lance Armstrong, 34, announced their split after two years of dating and an engagement that lasted a little over five months. Armstrong, a testicular cancer survivor, has raised money for cancer research through his Lance Armstrong Foundation. 　　

Crow underwent surgery in Los Angeles in a procedure she called "minimally invasive." On her web site, she said, "I am joining the more than 200,000 women who will be diagnosed with breast cancer this year. We are a testament to the importance of early detection and new treatments." 　　

She also said she would have to postpone her North American tour, which was scheduled for March and April. In addition, she suggested visitors contact the Lance Armstrong Foundation's LIVESTRONG SurvivorCare to help other cancer survivors. 　

A spokesperson for the organization said in a statement released exclusively to PEOPLE: "The staff of the Lance Armstrong Foundation has tremendous admiration and respect for Sheryl. Her generosity and enthusiastic support for the LAF and thus millions of cancer survivors demonstrate the LIVESTRONG philosophy." 　　

"Sheryl's warmth and compassion for people with cancer is always evident," the statement continued. "If only a fraction of the energy and determination she directed towards our cause benefits her in the days to come, then her cancer will be no match for her spirit."