Progress in the diagnosis of and therapy for MDS

The WHO classification system of MDS 4^th edition was recently updated. This revision includes nomenclature changes, reflecting the policy of the revision team to emphasize morphological features over cytopenias. Other changes are 1) taking SF3B1 mutation status into account for the definition criteria of MDS-RS (ring sideroblasts), 2) allowing for one additional cytogenetic abnormality (excluding -7/del (7q)) to be diagnosed as 'MDS with isolated del (5q)', 3) sub-classifying MDS-U according to the reasons for being included in this category, and 4) changing the diagnostic rules for myeloid neoplasms with erythroid blast predominance. This session also deals with recent topics in hematopoietic stem cell transplantation (HSCT) as an example of progress in therapy for MDS. Although HSCT is the only curative therapy for MDS, high treatment related mortality precludes its applicability especially for elderly patients, for whom demethylating agents are an alternative. Recently, reports on both well-designed retrospective or prospective studies have validated the advantage of HSCT over demethylating agents for patients of comparatively advanced age with higher risk MDS. Optimal intensity of conditioning regimens for HSCT is another controversial topic for which preliminary results of randomized controlled trials have been released and will be introduced in this session.