Robin Roberts on MDS Diagnosis: I Will Beat This

Five years after beating breast cancer, Good Morning America anchor Robin Roberts announced to a national audience today that she has been diagnosed with myelodysplastic syndrome (MDS) a rare blood disorder that will require chemotherapy and a bone-marrow transplant.

Roberts, holding back tears, told viewers that her older sister is “a virtually perfect match” and will serve as her donor.

ABC has made public a letter Roberts wrote to GMA staffers, in which she says she learned of the disease "a few weeks ago, during a rather unpleasant procedure to extract bone marrow for testing.

"I [then] received word that I would interview President Obama the next day. 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 absurdity of life.”

Roberts plans to remain in her position while undergoing treatment, though she'll miss a "chunk of time" later this summer for the transplant. Robin added that doctors have said her age and fitness levels should play a key role in successfully confronting the illness.

The "bottom line," according to Roberts?

"I’ve been living with this diagnosis for awhile and will continue to anchor GMA. I love what I do and the people with whom I do it. Along with my faith, family and friends, all of you at ABC News give me the motivation and energy to face this challenge... I am going to beat this."