Recent advances in the classification and treatment of myelodysplastic syndrome

The French-American-British (FAB) classification for myelodysplastic syndromes (MDS) is widely accepted in the clinical practice. However, advances in medical science in recent years have prompted some alterations to this purely morphological classification. In the comprehensive new classification four categories are distinguished, such as I. Primary MDS, II. MDS with myeloproliferative features, III. Mutagen induced (secondary) MDS and IV. MDS with hereditary predisposition. Treatment of MDS patients is nowadays stratified according to age of patient, availability of an HLA-identical sibling donor and risk assignment. Therapeutic strategies have been inspired by either missionary approaches converting premalignant cells into normal behaviour or by crusader tactics destroying non-compliant elements at the expense of innocent bystanders. Since apoptosis appears to be final pathway by which the hematopoietic cells undergo premature cell death, reversal of apoptosis would be the principal goal in the missionary treatment. The rational approach to suppress apoptosis would either aim at eliminating inducers of apoptosis or at preventing apoptosis by the administration of factors that can shift the balance to cell survival. Intensive acute leukemia-type treatment studies showed complete remission rates varying from 15% to 64%. The prolonged cytopenia leads to high early death rate. Transplantation of allogeneic stem cells has proven to be the only curative treatment option, but the expense of considerable transplant related mortality. The elaboration of risk adapted treatment algorithms has been much facilitated by the publication of the International Prognostic Scoring System (IPSS), which uses marrow blast percentage, cytogenetic data and number of cytopenias to delineate low, intermediate (1 and 2) and high risk categories.