From PEOPLE Magazine Click to enlarge
Robin Roberts was understandably anxious. For weeks the Good Morning America anchor had been leaning on good friend (and former GMA colleague) Diane Sawyer and ABC's chief health and medical editor Dr. Richard Besser as she struggled with the news that she was once again facing a life-threatening illness: a rare blood disorder called myelodysplastic syndrome (MDS). As the pair gathered information about the best course of treatment, Roberts, a breast-cancer survivor, steeled herself for the fight ahead. "As ever," says Sawyer, "she was simultaneously rocked by the news and ready for what she had to do." On June 11, just moments before she shared the diagnosis with millions of GMA viewers, Roberts confessed to Sawyer and Besser, "I liked it better when it was just the three of us."

But that didn't stop her from bravely facing the cameras. Having already announced her breast-cancer diagnosis on GMA five years ago-and later appearing bald on-camera after she lost her hair to chemotherapy-the 51-year-old anchor said simply, "Here we go again." Roberts then revealed that she had been diagnosed with MDS, the blood disorder once called pre-leukemia because of its propensity to develop into leukemia, and would undergo a bone marrow transplant later this summer or fall. Fighting back tears, she said, "I am going to beat this. My doctors say it, and my faith says it to me."

Ironically, the chemotherapy that saved her life in 2007 was also the reason she had developed the blood disorder, which affects 18,000 people in the U.S. each year, about 350 of them as a direct result of having undergone cancer treatment. Besides being younger and more fit than most people with MDS, Roberts has another reason to be hopeful: While many people struggle to find a bone marrow donor, "my big sister is virtually a perfect match," Roberts said, as Sally-Ann Roberts, 59, a TV anchor in New Orleans, stood a few feet away, clutching hands with Sawyer. "Robin is very fortunate," Besser told PEOPLE, noting that tests show her sister is a better match than an identical twin.

Eager to shift the focus after her emotional broadcast, Roberts ordered in her favorite fried chicken for a private meeting with ABC staffers. A true "southern girl," says Sawyer, "she was craving some comfort food." In between hugs and tears, Roberts also asked coworkers not to treat her differently, echoing what she said on air about wanting them to proceed as if it were "business as usual"-even as she began chemotherapy that same day to kill precancerous cells in her bone marrow. (While this chemotherapy won't cause Roberts to lose her hair again, says Besser, it may leave her fatigued.)

After feeling lethargic during the spring, Besser told PEOPLE, Roberts visited her doctor in April and took a blood test, which showed she had anemia. That led to other tests that confirmed the rare disorder. While Roberts noted she will have to take off a "chunk of time" later to recover from the transplant, she plans to continue working until then. "That's Robin," says Sawyer, noting how "incredibly strong" her friend is.

Part of that strength, adds Sawyer, comes from the fact that Roberts, the youngest of four children, has a solid support system. When Roberts was battling cancer, sister Sally-Ann-who lost her first husband, Willie, to colon cancer—called her every day. Now, says Sawyer, "I know Sally-Ann would say it was just a great sense of 'Thank you, God!' when she realized she was a match." Roberts expressed that sentiment on the air, noting that despite the diagnosis, she still feels "freaking blessed." Later she added, "I've always been a fighter, and with all of your prayers and support, a winner."