Lower-risk
myelodysplastic syndromes (MDSs) are defined as having low or intermediate 1 risk by the International Prognostic Scoring System and are characterized mainly by
anemia in most cases. Supportive care--primarily
red blood cell transfusions--remains an important component of their treatment, but exposes patients to insufficient correction of
anemia, alloimmunization, and organ
iron overload (for which the role of
iron chelation remains debated). Treatment aimed at preventing
anemia recurrence should therefore be used whenever possible.
Erythropoiesis stimulating agents remain the first-line treatment of
anemia in most lower-risk MDS without del(5q), whereas
anemia of low-risk MDS with del 5q responds to
lenalidomide in two-thirds of the cases, but this
drug should be used cautiously because profound
cytopenias may occur initially. Treatment after failure of those first-line
therapies are disappointing overall, with many patients eventually requiring long-term transfusions, but encouraging results have been reported with hypomethylating agents and
lenalidomide. Selected patients respond to
antithymocyte globulins, and
thrombopoietin receptor agonists are under investigation in lower-risk MDS with
thrombocytopenia. Some patients, while remaining at a "lower risk" MDS level, have severe
cytopenias and/or poor prognostic factors, found using newer prognostic parameters, or resistance to treatment, making them urgent candidates for more intensive approaches, including allogeneic
stem cell transplantation.