When Robin Roberts announced nearly two months ago that she has myelodysplastic syndrome, she cautioned viewers that she might “miss a day here or there” from Good Morning America. Yet, this week’s abrupt hiatus from the show leaves fans wondering whether her declaration of “I’m going to beat this” may, in fact, be more difficult than they anticipated.

Myelodysplastic syndrome, or MDS, happens when the bone marrow is damaged by cancer treatments such as radiation or chemotherapy. It typically develops years later and – as in Roberts’ case – once the cancer is fully treated and in remission.

Just five years ago, viewers watched and rooted for Roberts to beat breast cancer. However, the life-saving chemotherapy she received back then has created yet another challenge.

Normally, the bone marrow’s job is to produce blood cells — namely, red cells, white cells and platelets. When the bone marrow is damaged, these cells are not produced properly.

Without red cells, the person can become anemic, weak and tired; without white cells, the person doesn’t have an adequate immune system and cannot fight off infections. Without platelets, the blood doesn’t clot properly and can lead to abnormal bruising and bleeding.

Even so, some people with MDS do not show signs or symptoms. For them, the diagnosis ends up being an incidental finding after blood work is drawn for another reason.

Roberts is one of 10,000 cases diagnosed each year.

“If you Google MDS, you may find some scary stuff, including statistics that my doctors insist don’t apply to me,” Roberts wrote in her public letter back in June. “They say I’m younger and fitter than most people who confront this disease and will be cured.”

The fact that Roberts is under 60 is a plus. The person’s age, whether he or she has other health issues, and the severity of anemia are all major factors in how long a person with MDS survives.

There are also different grades of MDS — ranging from low-risk to high-risk. Two scoring systems estimate survival at about 12 years for the mildest forms of the disease. The more severe forms can have a survival time as short as five months.

The treatments aim to prolong life by improving production of those important blood cells. Two main treatments involve chemotherapy and a bone marrow transplant — where healthy bone marrow cells from one person are transplanted into the person with MDS.

Roberts has opted for both. She’s reportedly receiving chemotherapy treatments in preparation for a bone marrow transplant from her sister — who, in her words, “is an excellent match, and this greatly improves my chances for a cure.”

It is unclear how long Roberts’ hiatus will last, and what this time off says about her overall condition. This announcement comes earlier than the leave of absence she originally planned for the transplant.

Dr. Tyeese Gaines is a physician-journalist with over 10 years of print and broadcast experience, now serving as health editor for theGrio.com. Dr. Ty is also a practicing emergency medicine physician in New Jersey. Follow her on twitter at @doctorty.