Myelodysplastic Syndromes with Hypocellular Marrow: Clinical Characteristics and Evaluation of Outcome

Background. MDS may be characterized by hypocellular marrow, irrespective of their WHO classification or molecular characteristics. Their prognostic weight must still be completely evaluated. MDS with hypocellular marrow tend to be considered an aplastic anemia "overlap syndrome" or a pre-aplastic anemia stage. There are no strong specific therapy recommendations, and large studies analyzing the outcome of hypocellular MDS are lacking. While selective sensitivity to immunosuppressive therapy is suggested, evidence in this sense is controversial. Aims. We wanted to evaluate the clinical characteristics, outcome and choice of therapy of patients with hypocellular MDS and compare them with normocellular MDS. Methods. We analyzed 2559 MDS cases with complete clinical annotations and with evaluable bone trephine biopsy, enrolled in our Italian National Registry FISMonlus. In this cohort of patients, 438 had a bone marrow cellularity Results. In FISM cohort median age was 72.5 yrs in the hypocellular group and 72,3 yrs in the normocellular group; M/F were 53.2%/46.8% for hypocellular MDS vs 62.6%/37.4% in normocellular MDS. IPSS-R risk categories were distributed as follows: Hypocellular MDS Very Low 15.5%, Low 35.1%, Intermediate 30.1%, High 11.3%, Very high 8%; Normocellular MDS Very Low 12.8%, Low 37.2%, intermediate 23.7%, High 15.5%, Very High 11.4%. Global median overall survival (OS) was 77 months for hypocellular MDS and 56 months for normocellular MDS. When OS was evaluated in the different IPSS-R risk groups, Lower risk MDS cases with hypocellular BM had a median OS of 125 mos while normocellular had a median OS of 74 mos (p Conclusion. Our results are based on an unbiased analysis of "real life" MDS patients with hypocellular BM compared to normocellular ones. Clinical characteristics between the two groups were not significantly different in terms of age, gender, and distribution in the various IPSS-R risk categories. The outcome of the hypocellular marrow-MDS cases was better in comparison with that of normocellular MDS, with significantly longer OS in IPSS-R lower risk cases. The advantage in OS for hypoplastic MDS wasn9t present for IPSS-R higher risk cases. Finally, the choice of first line therapy doesn9t seem to be influenced by the BM cellularity, with a surprising very low proportion of patients receiving immunosuppressive agents, despite several guideline recommend of this treatment for hypoplastic MDS. Disclosures Santini:Novartis: Honoraria; Otsuka: Consultancy; Celgene: Honoraria, Research Funding; AbbVie: Membership on an entity9s Board of Directors or advisory committees; Amgen: Membership on an entity9s Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity9s Board of Directors or advisory committees. Finelli:Novartis: Consultancy, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Gaidano:Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Morphosys: Honoraria; Roche: Consultancy, Honoraria. Oliva:Celgene: Consultancy, Other: Royalties, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; La Jolla: Consultancy; Sanofi: Consultancy, Speakers Bureau. Cilloni:celgene: Membership on an entity9s Board of Directors or advisory committees; Janssen: Membership on an entity9s Board of Directors or advisory committees.