"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 later this year.
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.
Roberts, 51, said she contracted the disease through her treatment for the breast cancer.
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.
Between 80 percent and 90 percent of MDS patients develop it when they're over age 60, according to the American Cancer Society. 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.
On a day some of her bone marrow was extracted for testing earlier this year, 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.