Good Morning America anchor Robin Roberts, a breast cancer survivor, announced Monday morning that she is suffering from myelodysplastic syndrome and will begin treatment immediately.

Continue reading

The MDS diagnosis, which used to be more commonly known as "preleukemia," comes several years after she found out she had breast cancer.

Roberts made the announcement that she has MDS on Good Morning America and on ABCNews.com.

WATCH: Roberts announces her diagnosis on GMA (ABCNews.com)

"Sometimes, while getting treatment for cancer, it can lead to other medical problems, and that's what happened," Roberts said.

MDS is a malignant disorder of bone marrow, which according to marrow.org can affect more than 15,000 people per year. However, experts say that only about 350 per year get the disorder as a result of cancer treatment.

Roberts says that she'll need a bone marrow transplant, which she says she will receive from her sister. She began treatment on Monday, shortly after the emotional announcement, which she made in the presence of the entire Good Morning America staff.

She'll continue to anchor ABC's daily, national morning show while undergoing treatment.

In July of 2007, Roberts announced she was suffering from breast cancer, from which she has recovered.

You can read Roberts' first-person explanation on ABCNews.com.

ABC 7's Justin Karp contributed to this report.