Hypocellular Myelodysplastic Syndrome in the Hypomethylating Agent Era

Abstract

ABSTRACT Aim: Hypocellular myelodysplastic syndrome (MDS) represents 10 ∼ 15% of total MDS cases. Several studies reported that hypocellular MDS had some different clinical and pathologic features as compared to those of normo/hypercellular MDS. However, the treatment strategy and prognosis of hypocellular MDS has not been well-defined, especially in the epigenetic therapy era. In this study, we evaluated the clinical characteristics of hypocellular MDS and responses to the hypomethylating agent compared with normo/hypercellular MDS. Methods: Total 51 patients who diagnosed as de novo MDS, and treated with hypomethylating agent between 2006 and 2012 were enrolled. Clinical parameters including laboratory findings at diagnosis and during treatment with hypomethylating agents, treatment response and survivals were analyzed retrospectively. Hypocellular MDS was defined as bone marrow cellularity less than 30% in patients younger than 70 years, or less than 20% in patients older than 70 years. Clinical characteristics and treatment outcomes between hypocellular MDS and normo/hypercellular MDS were compared. Results: Patients with hypocellular MDS showed a lower white blood cell count (2.08 x 103/µL vs. 2.88 x 103/µL, p = 0.036) and a higher erythropoietin level (1353 mIU/mL vs. 110 mIU/mL, p = 0.005) than normo/hypercellular MDS. The age, gender, absolute neutrophil count, hemoglobin level, platelet count, number of cytopenia, IPSS cytogenetics and IPSS risk groups were not significantly different between the groups. The overall response rate (14% vs. 23%, P = 0.334) and hematologic improvement rate (20% vs. 36%, P = 0.196) were slightly lower in hypocellular MDS, but did not show any statistical significance. Overall survival, progression free survival, and leukemia free survival after the initiation of the hypomethylating agent in hypocellular MDS were not significantly different from those of normo/hypercellular MDS. Conclusions: Patient with hypocellular MDS treated with the hypomethylating agents showed comparable response rates and survival rates with those with normo/hypercellular MDS. The hypomethylating agents seem to be one of feasible treatment options in hypocellular MDS, as well as in normo/hypercellular MDS. Disclosure: All authors have declared no conflicts of interest.