Monosomal and complex karyotypes as prognostic parameters in patients with International Prognostic Scoring System higher risk myelodysplastic syndrome treated with azacitidine.

Background: Azacitidine (AZA) is standard care for patients with myelodysplastic syndrome (MDS) who have not had allogeneic stem cell transplantation. Chromosomal abnormalities (CA) including complex karyotype (CK) or monosomal karyotype (MK) are associated with clinical outcome in patients with MDS.

Methods: We investigated which prognostic factors including CAs would predict clinical outcomes in patients with International Prognostic Scoring System (IPSS) higher risk MDS treated with AZA, retrospectively. CK was defined as the presence of three or more numerical or structural CAs. MK was defined as the presence of two or more distinct autosomal monosomies or single autosomal monosomy with at least one additional structural CA.

Results: A total of 243 patients who treated with AZA, were enrolled. CK was present in 124 patients and MK was present in 90 patients. Bone marrow blasts ≥15% and CK were associated with poorer response (P=0.038, P=0.007) and overall survival (OS) (P<0.001, P<0.001) independently. Although MK in CK group was not associated with prognosis, non-MK status in non-CK group reflected favorable OS (P=0.005). The group including >3 CAs was associated with poorer OS (group including <3 CAs vs. only three CAs, P=0.001; group with >3 CAs vs. only three CAs, P=0.001).

Conclusion: CK was an important prognostic parameter associated with worse outcome. MK may predict poor survival in only non-CK status. The higher number of CAs was associated with poorer survival.