What is pediatric MDS, and why is it seldom mentioned in larger discussion about MDS?
There are several classification systems used for identifying subtypes and their potential severity and risk levels of MDS in the adult patient population. Do these classifications also apply to pediatric MDS?
That’s a good question. They can apply and we do our best to apply those classification systems. We have attempted to fit pediatric MDS into the World Health Organization (WHO) classification system, but it’s not optimal for this. This is because there are certain subtypes of MDS, for example, refractory anemia with ringed sideroblasts (RARS), that don’t occur in children. Another interesting point is that one-third to one-half of children with MDS has an associated constitutional abnormality that can play a large part in the child developing MDS. The most common ones are Down Syndrome and inherited bone marrow failure diseases such as Fanconi Anemia. Those are difficult to classify in the adult systems because they generally don’t take inherited abnormalities into account.
Another issue is that familial MDS is not uncommon in children with MDS. Many young MDS patients will have siblings who also have MDS. We have had a few families we have treated with familial monosomy 7-related MDS, and that doesn’t occur on the adult side. Finally, some of the subsets of cytogenetic abnormalities that occur in MDS are very different in children. A larger proportion of children have monosomy 7 compared to adults, and a much small proportion of children have the 5q-minus variant – this one is almost never seen in children.
Do the several different treatment approaches (watch and wait, supportive care, active treatment including stem cell transplantation) used in adult MDS apply to pediatric MDS?
Has there been any promising recent research with regard to pediatric MDS?
Because pediatric MDS is so heterogeneous, most of the research occurring is more in the conditions that can predispose to MDS, or make it more likely for pediatric MDS to occur. For example, with Down syndrome-related MDS, there have been striking advances in the understanding of what causes it and the development of different treatments that can help. There have also been advances in understanding the genetic causes of various bone marrow failure syndromes. But those haven’t yet translated into better therapies for pediatric MDS once it develops - bone marrow transplant remains the treatment of choice.
What do parents of children diagnosed with pediatric MDS most need to know?
There are two points here. We consider pediatric MDS to be a curable condition as long as a patient can have an allogeneic bone marrow transplant. Just like with recurrent MDS, bone marrow transplantation doesn’t guarantee a cure. However, the proportion of pediatric patients for which we can find a suitable donor and who can tolerate a transplant is so high that we can reasonably be very optimistic about pediatric patients diagnosed with MDS.
It’s also important to say that any parent of a child diagnosed with a rare blood or bone marrow malignancy like pediatric MDS should be treated at a specialized pediatric oncology center. It should one that has a lot of experience with these conditions and that also has a collaborative relationship with their adult oncology colleagues, who see many more cases of MDS and can be a great source of expertise and advice.
Dr. Brown is an expert in the diagnosis and treatment of cancer in children and young adults. His primary area of expertise is in the area of blood cancers, including leukemia and lymphoma. He is a leader within the international Children’s Oncology Group (COG) consortium, serving on the executive steering committees for both acute lymphoblastic leukemia (ALL) and myeloid disorders. He is the principal investigator of active clinical trials for leukemia in COG and in the pediatric oncology experimental consortium (POETIC) and therapeutic advances in childhood cancer (TACL) pediatric phase I consortia, which are investigating novel targeted agents in childhood cancer. He co-chairs the National Comprehensive Cancer Network (NCCN) ALL Panel.