Purpose. The positive lenalidomide experience in lower risk myelodysplastic syndrome (MDS) with deletion 5q and red blood cells transfusion dependence resulted in its broad use in MDS. The study aim was to define the prognosis in MDS and deletion 5q with or without other cytogenetic abnormalities.

Patients and Methods. Patients with MDS (<20% blasts) and evaluable cytogenetic studies (1966-present) were reviewed. Outcome of patients with deletion 5q or with loss of chromosome 5 (monosomy 5) was evaluated by the presence or absence of additional chromosomal abnormalities, overall, and in “lower risk” MDS.

Results. Of 2743 patients analyzed, 287 (10%) had deletion 5q, and 216 (8%) had monosomy 5 abnormalities. The median survival was 9 months with deletion 5q, 6 months with monosomy 5, and 17 months without a chromosome 5 abnormality. Considering patients with deletion 5q, the median survival was 33 months with deletion 5q alone, 17 months with deletion 5q and one additional abnormality, but only 6–12 months with deletion 5q and ≥ 2 abnormalities or chromosome 7 abnormality. Only 93 patients (3.4% of total) had lower risk MDS (International Prognostic Scoring System low or intermediate 1) and deletion 5q; their median survival 29 months (2-year survival 60%), and ranged from 13 to 41 months depending on the presence or absence of additional chromosomal abnormalities. Among 58 patients with lower risk MDS deletion 5q with identical entry criteria to the original lenalidomide study, the median survival was 44 months and the 2-year survival rate 80%. Among 198 patients with MDS with deletion 5q and < 10% blasts (a subset now often offered lenalidomide) the median survival was 12 months. Monosomy 5 was significantly more frequently associated with advanced MDS and with other chromosomal abnormalities. Considering only patients with IPSS intermediate 2 or high risk, the survival was better with deletion 5q versus monosomy 5 (medians 7 versus 6 months; p = 0.005).

Conclusions. The prognosis of MDS with chromosome 5 abnormalities is heterogeneous. This study provides baseline expectations of outcome in different MDS subsets and deletion 5q, which could be used for comparative purposes with the lenalidomide experience.

Disclosures: Borthakur:Celgene: Research Funding.

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