Clinical course of refractory anemia with ring sideroblasts, marked thrombocytosis better defined

Issue: May 25, 2012

Refractory anemia with ring sideroblasts and marked thrombocytosis should be considered a distinct entity, as outcomes of patients with the conditions varied from comparison arms in a recently published study.

Despite having been classified as a distinct myeloid neoplasm by the WHO in 2001, the existence of refractory anemia with ring sideroblasts and marked thrombocytosis (RARS-T) as a single entity has been disputed. In order to better define the clinical features of RARS-T, researchers conducted a collaborative study across 16 European centers. The study included 200 patients with the condition.

Each enrolled patient with RARS-T was matched to a patient with RARS. In addition, these patients were compared against 454 patients with essential thrombocythemia.

Patients with RARS-T had higher hemoglobin level (P=.032), white blood cell count (P<.001), platelet count (P<.001) and percentage of ring sideroblasts (P<.001) compared with patients with RARS. Patients with RARS-T also had higher mean corpuscular volume than patients with essential thrombocythemia.

Patients with RARS-T had shorter OS than patients with essential thrombocythemia (P<.001) but longer survival than those with RARS (P<.001). Among patients with RARS-T, JAK2 mutation status and platelet threshold had no effect on survival.

Thrombotic events occurred at a similar rate among patients with essential thrombocythemia and RARS-T, but they were more frequent in patients with RARS.

“The clinical course of refractory anemia with ring sideroblasts and marked thrombocytosis is better than that of refractory anemia with ring sideroblasts and worse than that of essential thrombocythemia,” the researchers wrote. “The higher risk of thrombotic events in this disorder suggests that anti-platelet therapy might be considered in this subset of patients.”

References:

Broseus J. Haematologica. 2012;doi:10.3324/haematol.2011.053918.