Prognostic impact of severe thrombocytopenia in low-risk myelodysplastic syndrome

BACKGROUND: Thrombocytopenia is very common in myelodysplastic syndrome (MDS); however, its clinical impact in low-risk patients remains controversial. METHODS: The authors analyzed the incidence and prognostic significance of thrombocytopenia at diagnosis in 2565 de novo MDS patients included in the Spanish MDS Registry. RESULTS: Thrombocytopenia (platelet count <100 x 10(9)/L) was identified in 842 patients (32.8%). Severe thrombocytopenia (platelet count <30 x 10(9)/L) was observed in 7.1% of patients and was significantly associated with a higher-risk World Health Organization subtype (P=.026) and intermediate-2/high-risk International Prognostic Scoring System (IPSS) score (P=.046). Severe thrombocytopenia was the most important prognostic factor and had negative effects on the low/intermediate-1 risk group. Median overall survival of patients with a platelet count <30 and >= 30 x 10(9)/L was 16 months and 71 months, respectively (hazard ratio, 4.66; 95% confidence interval, 2.74-7.90; P<.0001). The negative effect of severe thrombocytopenia in low/intermediate-1 risk patients was caused by increased risk of bleeding. CONCLUSIONS: MDS patients with low/intermediate-1 IPSS risk score and severe thrombocytopenia should no longer be regarded as low risk, and must be considered for disease-altering approaches at diagnosis. Cancer 2011; 117: 5529-37. (C) 2011 American Cancer Society.