The WHO classification of MDS does make a difference

Abstract

The purpose of this study was to determine the facility and reliability of the World Health Organization (WHO) classification of myelodysplastic syndromes (MDSs) with several observers reviewing the same diagnostic specimens. We also wanted to determine if the WHO classification provided additional information about predictability of clinical response outcome. To accomplish these goals we reviewed 103 previously diagnosed cases of low-risk MDS. We found 92% interobserver agreement (P < .001). Sixty-four of these patients had been entered into clinical trials using growth factors by the Nordic MDS Study Group. The WHO classification reliably predicted therapeutic response to the combination of granulocyte colony-stimulating factor (G-CSF) and erythropoietin (Epo). The response rate differed significantly between refractory anemia with ringed sideroblasts (RARS) and refractory anemia with multilineage dysplasia and ringed sideroblasts (RCMD/RS) with regard to therapeutic response (75% versus 9%; P ‫؍‬ .003). Also, in the group of patients with less than 5% marrow blasts, there was a difference in median survival between patients with unilineage dysplasia (51% surviving at 67 months) and those with multilineage dysplasia (median survival, 28.5 months;

A new disease categorization of low-grade myelodysplastic syndromes based on the expression of cytopenia and dysplasia in one versus more than one lineage improves on the WHO classification

“…However, partly owing to the uneven distribution of patients, and partly owing to the increased number of subsets still based on the FAB framework, many subgroups are indistinguishable from each other. 11,19-21 Howe et al 21 concluded in their study of the WHO classification that the increased number of diagnostic categories will make application of statistics in studies impossible unless patient groups are extremely large. This raises the question if the sub-categorization of the WHO is based on arbitrary 'splitting' instead of evidencebased 'lumping'.…”

“…18 We applied the WHO criteria on a low-risk MDS population and agree with other investigators that, overall, there are significantly different sub-sets for survival and disease evolution. 11,[19][20][21] Multilineage dysplasia in MDS does indeed confer unfavorable survival compared to unilineage dysplasia. However, partly owing to the uneven distribution of patients, and partly owing to the increased number of subsets still based on the FAB framework, many subgroups are indistinguishable from each other.…”

“…As expected and in accordance with the findings of others, in the WHO we could not distinguish the outcome of RA from that of RARS, or RCMD from RCMD-RS. 11,21,22 In fact, the lumping together of certain WHO categories have increasingly been advocated. 11,22 Moreover, in our hands, many straightforward MDS cases defied classification into the WHO framework.…”

Novel therapies for myelodysplastic syndromes

“…Although it is an advance over the FAB classification system, the WHO nomenclature still is based on morphology and blast counts, and whether it can capture the clinical heterogeneity of MDS remains to be seen. 22 The International Prognostic Scoring System (IPSS) is based on the percent of bone marrow blasts, the presence of cytogenetic abnormalities, and the degree of cytopenia (Table 2). 23 It assigns points to each of the factors and divides patients into low, intermediate-1, intermediate-2, and high-risk groups with corresponding median survival times of 5.7 years, 3.5 years, 1.2 years, and 0.4 years, respectively.…”

The role of lenalidomide in the management of myelodysplasia with del 5q

“…By reviewing published series of MDS treated with erythropoietin (EPO) ± granulocyte colony-stimulating factor (G-CSF), we found 11 responses in 41 treated patients with del 5q (Greenberg et al, 1997;Hellstrom-Lindberg et al, 1998;Howe et al, 2004) (Table III). This response to EPO, with or without G-CSF, seemed to be lower in del 5q MDS than in other low-risk MDS.…”