Clinical and Biological Characterization of Low Risk MDS Patients According to Ring Sideroblasts (RS). Comparison between the 3 Subgroups in WHO2017 Classification. Study from the Spanish MDS Registry

BACKGROUND: An important progress has been made in understanding the pathophysiology of lower risk MDS in recent years. This progress has been more relevant in some specific subtypes such as del(5q) MDS or MDS with RS (>15% RS in BM or >5% RS + SF3B1 mut). In fact, for the latter subtype, in-depth knowledge of its pathophysiology has led to the recent development of new therapeutic strategies (luspatercept). In this regard, new WHO 2017 classification identify in the lower risk MDS setting 2 categories of patients with different clinical and biological features: those without RS (<5%) and those with RS, involving 2 subgroup of patients (those with >15% of RS and those with <15% and >5% of RS and the presence of SF3B1 mutations. Unfortunately, no clear data regarding disease characteristics and outcome have been analyzed to identify these 3 new subgroups of patients, are those with 5-15RS really like those with >15RS? Therefore, improving knowledge in real life setting of these subgroups of patients will lead to optimize the therapeutic management and the potential development of new therapeutic strategies.