OS21-07 – MDS very poor risk

During EBMT 2025, Prof Dr Xavier Poiré, hematologist at the Cliniques Universitaires Saint-Luc in Brussels presented the results of an analysis performed by the EBMT chronic malignancies working party looking into the outcome of MDS patients with very poor risk cytogenetics after an allogenic stem cell transplantation (alloSCT).

In the revised international scoring system (IPSS-R) for MDS, very poor risk cytogenetics is defined as having by three or more cytogenetic abnormalities. This group is very heterogeneous, and the presented analysis therefore retrospectively evaluated post alloSCT outcomes in MDS patients with very poor risk cytogenetics, assessing the impact of individual cytogenetic features. These abnormalities include abnormalities in chromosome 7q (abn7q), 5q (abn5q), 17p (abn17p), 3q26 (abn3q26), the presence of a monosomal karyotype (MK) and the total number of cytogenetic abnormalities.

The presented analysis included 580 patients with a median age of 60 years. The most common adverse cytogenetic features in these patients consisted of MK (n=448, 78%), abn5q (n=444, 77%), abn7q (n=349, 61%), abn17p (n=194, 34%) and abn3q26 (n=81, 14%). Overall, the 5-year probability of overall (OS) and progression-free survival (PFS) among these patients was 21% and 19%, respectively. 

In a second step, patients were hierarchically classified in patients with none of the above assigned adverse cytogenetic features (n=23); MK without any other adverse feature (n=21); abn7q without abn5q, abn17p, or abn3q26 (n=36); abn5q without abn17p or abn3q26 (n=229); abn17p without abn3q26 (n=156); and patients with abn3q26 (n=77). This process identified two distinct subgroups with a markedly different prognosis: one with a very unfavorable profile, defined by the presence of abn5q, abn17p, or abn3q26, and one with a more favorable prognosis. The 5-year probability of OS was 18% for unfavorable patients and 46% in the favorable subgroup (p<0.001). Corresponding 5-year PFS-rates were reported at 16% and 43%, respectively. Finally, also the presence of 6 or more cytogenetic abnormalities proved to be associated with a worse OS and PFS.

In conclusion, this analysis revealed a subgroup of MDS patients with very poor cytogenetics according to the IPSS-R that have a more favorable outcome after alloSCT.