NEW YORK -- "Good Morning America" anchor Robin Roberts said she is starting chemotherapy Monday for treatment of a disease that will require her to get a bone marrow transplant sometime this fall.
ABC's Roberts, who was treated for breast cancer five years ago, said she's been diagnosed with myelodysplastic syndrome, a blood and bone marrow disease once known as preleukemia.
The chemotherapy is a preparatory treatment for the bone marrow transplant. Roberts said her sister is a good match and has agreed to donate bone marrow.
"My doctors tell me I'm going to beat this, and I know it's true," Roberts said on the show Monday.
Roberts, 51, said she contracted the disease through her treatment for the breast cancer.
Between 80 percent and 90 percent of MDS patients develop it when they're over age 60, according to the American Cancer Society. Roberts said there's some "scary stuff" when you look up statistics about the disease, but ABC medical correspondent Dr. Richard Besser said these statistics don't shed much light on Roberts' case because she's "young and incredibly healthy" in comparison to most people who contract the disease.
Roberts has been on "Good Morning America" for a decade, most recently teamed with George Stephanopoulos as co-anchor. The show has been doing well this spring in its ratings competition with NBC's "Today" show.
She learned of her diagnosis on the same day that "Good Morning America" beat "Today" for a week in the ratings for the first time in more than 16 years, Roberts said. On a day some of her bone marrow was extracted for testing, Roberts learned she had landed an interview with President Barack Obama where the president revealed his support for gay marriage.
"The combination of landing the biggest interview of my career and having a drill in my back reminds me that God only gives us what we can handle and that it helps to have a good sense of humor when we run smack into the adversity of life," she said.