As sweat, out friend, our colleague, our robin roberts made an announcement today. She is ready to embark on her bone marrow transplant. The next phase in her battle against a rare blood disorder.... See More
As sweat, out friend, our colleague, our robin roberts made an announcement today. She is ready to embark on her bone marrow transplant. The next phase in her battle against a rare blood disorder. She'll be taking her leave from "good morning america" starting friday. And she has already inspired 36,000 new donors to sign up with be the match bone registry. A spike of more than 50%, and now she's inspiring us yet again. Tonight, abc's sharyn alfonsi tells about you about robin and the life ahead. Reporter: From that couch, where she's been a fixture for so many years, robin roberts broke the news. Friday, george, will be my next day, I will check into the hospital the following tuesday and begin the process. Reporter: It starts for chemotherapy in preparation for her bone marrow transplant and treatment of myelodysplastic syndrome, or mds. A disease where the bone marrow doesn't make enough healthy blood cells. Each year, as many as 10,000 americans are diagnosed with mds. Only 300 cases are from cancer treatments like robin's. So how will doctors try to replace robin's sick cells with healthy ones? First, the chemotherapy to wipe out all robin's problematic cells so her body will accept the good cells from her donor. Her sister, sally ann, swapped with robin this weekend -- her marrow, a perfect match. Robin will be given an iv full of her sister's stem cells which will begin to rebuild her bone marrow. The procedure will take about 30 minutes. Robin will actually be fully awake. Then the waiting begins. Doctors will be monitoring her blood count closely. We have to give antibiotics and blood products and immune system-regulating medications to keep the patient's body in good shape and accepting the new cells. Reporter: Robin will remain in the hospital for weeks, possibly months. Doctors say her prognosis is excellent, but as her body heals, her immunity will be so compromised. She told viewers this morning she had to send her beloved dog, k. To maine to stay with friends. Robin shared she can't wait to get her friend back. So many of us feeling the same way. Sharyn alfonsi, abc news, new york. And all this week, of course, "good morning america" will be telling us more about robin's journey. And if you want to learn more about becoming a donor, please head to abcnews.Com. As always, team robin is standing by for her.
This transcript has been automatically generated and may not be 100% accurate.