ABC News' Amy Robach Diagnosed with Breast Cancer

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ABC News correspondent Amy Robach, 40, has been diagnosed with breast cancer.

Sitting with her husband Melrose Place actor Andrew Shue, Robach revealed her diagnosis on Good Morning America Monday morning. In an accompanying blog post she wrote herself, Robach explained that she found out that she had cancer after she underwent her first mammogram live on air for "GMA Goes Pink" day on October 1.

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"Sitting in that kitchen with Marie Monville [the wife of Amish school shooter Charles Roberts, whom she was interviewing at the time], I had cancer and didn't know it. In fact, I would have considered it virtually impossible that I would have cancer," Robach wrote. "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."

As for what her next steps are, she shared that she will undergo a double mastectomy on November 14, followed by reconstructive surgery.

But despite the shocking news, Robach is grateful that she was encouraged to undergo the mammogram in the first place by several producers and also GMA anchor Robin Roberts, who herself is both a breast cancer and myelodysplastic syndrome (MDS) survivor.

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" ... 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," she wrote. "The doctors told me bluntly: 'That mammogram just saved your life.'"