On Monday, "Good Morning America" co-host Robin Roberts, 51, announced to the nation that the treatment that saved her life five years ago may have contributed to a new diagnosis that [some medical groups say is harder to fight](http://marrow.org/Patient/Disease_and_Treatment/About_Your_Disease/MDS/M...(MDS). Robins was diagnosed with myelodysplastic syndrome (MDS), a group of diseases that affect the bone marrow and blood. The disease can be caused by past chemotherapy treatment or radiation therapy, [according to the National Marrow Donor Program.](http://marrow.org/Patient/Disease_and_Treatment/About_Your_Disease/MDS/M...(MDS).aspx) In a story published on ABC News' website titled "I'm Going to Beat This" Robins said she learned about her diagnosis on the same day in April that her show beat out NBC's "Today Show" in the ratings for the first time in nearly 16 years. "Talk about your highs and lows!" "Then a few weeks ago, during a rather unpleasant procedure to extract bone marrow for testing, I received word that I would interview [President Obama the next day](http://colorlines.com/archives/2012/05/thank_michelle_sasha_and_malia_fo...)," Roberts said. "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." "Sometimes the treatment for cancer can cause other serious medical problems," Robins told viewers Monday morning. "My doctors tell me I'm going to beat this -- and I know it's true," Roberts said. "Bone marrow donors are scarce and particularly for African-American women," she said. "I am very fortunate to have a sister who is an excellent match, and this greatly improves my chances for a cure."