GMA's Amy Robach Diagnosed with Cancer After on-Air Exam

Good Morning America anchor Amy Robach underwent a routine mammogram live on the air last month as part of a segment on women's health. And the procedure may end up saving her life.

On Monday, Robach revealed that when she went to get the results of the screening, she was diagnosed with breast cancer and now plans to have a double mastectomy.

Robach said she was initially reluctant to have the mammogram when producers approached her about it. But she eventually agreed, and had the exam on the air on Oct. 1.

November Sweeps roundup: See what your favorite shows have planned

"That day, when I was asked to do something I really didn't want to do, something I had put off for more than a year, I had no way of knowing that I was in a life-or-death situation," she wrote in a blog post Monday. "Sitting in that kitchen with Marie Monville, I had cancer and didn't know it. In fact, I would have considered it virtually impossible that I would have cancer. I work out, I eat right, I take care of myself and I have very little family history; in fact, all of my grandparents are still alive."

Robach says she plans to have the mastectomy on Nov. 14. "Only then will I know more about what that fight will fully entail, but I am mentally and physically as prepared as anyone can be in this situation," she writes. "And while everyone who gets cancer is clearly unlucky, I got lucky by catching it early, and there are so many people to thank for making sure I did. Every producer, every person who urged me to do this, changed my trajectory."

Watch Robach talk about her diagnosis below: