When Good Morning America co-anchor Robin Roberts revealed through tears on national television last month that she has myelodysplastic syndrome, millions of viewers likely were hearing of the blood disorder for the first time.

Just two weeks later, when writer and filmmaker Nora Ephron died of acute leukemia, most media reports did not explain that myelodysplastic syndrome predisposed the blood cancer that ended her life.

It’s no wonder that information about myelodysplastic syndromes, a collection of bone marrow blood disorders also called MDS, is not in the mainstream. Medical experts are still trying to figure it out.

Is MDS a blood cancer or not?

It’s complicated.

“The problem is that MDS represents a heterogenious [diverse] set of diseases. The syndrome is not the disease . It’s a variety of bone marrow mutations,” said Dr. Steven Fein, a hemotologist/oncologist at Baptist Health South Florida.

Simply, the bone marrow does not function properly, so patients develop life-threatening low blood cell and low platelet counts, said Dr. Stephen Nimer, director of the University of Miami’s Sylvester Comprehensive Cancer Center and president of the MDS Foundation. Symptoms can include fatigue, shortness of breath, bruising and bleeding.

MDS eventually obliterates bone marrow, which is the body’s stem cell blood production source, ground zero for the immune system and necessary to sustain life. Patients are rarely cured without a blood stem cell transplant or direct bone marrow transplant — as can happen for blood cancers like lymphoma, leukemia and myeloma.

“It wipes out the MDS and gives patients a new capability to create normal blood cells,” Nimer said.

Standard medications include the chemotherapy drugs 5-azacytidine, decitabine and lenalidomide.

MDS was called pre-leukemia until the 1970s when the term was dropped because only about 30 percent of MDS patients actually develop leukemia.

“Sometimes cancers are successfully treated and people survive, but there is that small group who can get leukemia or MDS from the treatment,” Nimer said.

Up to 2 percent of people with MDS are former cancer patients.

Roberts, during her broadcast revelation, said her MDS is likely a side effect of the chemotherapy she endured for breast cancer five years ago.

“Sometimes treatment can lead to other serious medical issues and that’s what I am facing,” Roberts told viewers. “It’s about focusing on the fight and not the fright.”

About 60,000 bone marrow or stem cell transplants are performed annually in the United States?, said Dr. Lyle Feinstein, director of the blood and marrow transplant program for Memorial Cancer Institute at Memorial Hospital West in Broward County.

Feinstein believes MDS is too much like cancer to be considered otherwise.

“MDS is a cancer — but not leukemia, yet. It is a bone marrow disorder where the blood stem cells become zero count and ultimately the disease can transform into cancer. It is a fallacy that it is not cancer,” Feinstein said.

Keiren Joyce, 66, of Hollywood, recently underwent a stem cell transplant using his own blood taken before a weeklong battery of chemotherapy for lymphoma. Joyce allowed The Miami Herald to document the 60-minute procedure.

“He said if it helps anyone learn about stem cell transplant, then he’s all for it,” said his wife Mary Joyce, who sat at the edge of her husband’s hospital bed during the process.

Feinstein, who oversaw the transplant, said Joyce’s earlier chemotherapy treatments for lymphoma left his bone marrow decimated of healthy cells — much like what can happen to other cancer patients under intense chemo. But because Joyce had not developed MDS, his own previously harvested healthy blood was used for transplant.

MDS patients are the least likely candidates for stem cell transplants because MDS usually occurs in elderly people, 70 years or older, who are too infirm to withstand the rigors of a bone marrow transplant. Further, though some patients with blood cancers can use their own pre-chemo blood to replenish damaged stem cells, MDS patients require family or unrelated donors.

And therein lies another problem, according to the The National Marrow Donor Program. Only 25 percent of people who need bone marrow transplants are compatible with family members - the rest depend on the national registry to find matches with people of similar heritage.

Although 9.5 million people are registered to be donors through the program’s Be the Match campaign, the majority are Caucasian. While 90 percent of white patients are able to find matches, only 60 percent of minority patients are matched.

Since the morning Roberts went public with her disease through July 5, 17,500 people have signed up to become donors. Typically, about 9,000 sign up per month.

Roberts, 51, will receive a bone marrow transplant from her sister, an uncommon perfect sibling match.

Meanwhile, MDS, which is frequently described as “rare,” is not so rare. About 17,000 Americans a year will contract the disease. U.S. Marine Sgt. Ken Reich, 26, of Miami Springs was diagnosed in May 2011 while stationed in Okinawa, Japan. He also had served in Iraq.

“My master sergeant tried to make me feel better about having MDS by telling me only 20 percent of people die of the disease. Then he said that means one of every five people die. I guess I’m lucky so far,” Reich said during a recent treatment at Sylvester Comprehensive Cancer Center at University of Miami Hospital.

Like Roberts, Reich has age, stamina and determination in his corner.

With a bone marrow transplant already under his belt, Reich is now undergoing the only photopheresis therapy available for MDS in South Florida, at Sylvester. The therapy runs his new blood through a photosensitive compound and UV light to stimulate his new blood cells against rejection.

Reich was among the first patients treated at the Sylvester transplant inpatient unit when it opened in September. The center is the only one in South Florida to perform bone marrow stem cell transplants for MDS patients.

“This is worse than war. In Iraq any one of my friends would jump on a grenade for me. Here, I have support but it’s me against the disease,” Reich said.