Thrombocytopenia Predicts for Poor Survival In Patients with Lower Risk Myelodysplastic Syndromes (MDS)

Abstract 4021

The incidence of thrombocytopenia in MDS is reported to be as high as 40–60% in various reports and is more commonly seen in patients presenting with higher risk disease (∼80%) by International Prognostic Scoring System (IPSS) compared to Int-1 (∼50%) or low risk MDS (12%). Thrombocytopenic MDS patients are at an increased risk of bleeding and hemorrhagic complications have been reported in 3– 50% patients with fatal hemorrhage occurring in 14–20% cases. The prognostic significance of thrombocytopenia in lower risk MDS patients (low+Int-1 risk) has not been clearly defined. To determine whether thrombocytopenia in lower risk MDS patients affects survival, we performed a retrospective study of 1,402 patients diagnosed with MDS between 1987 and 2010. Of these, 687 patients were classified by IPSS as follows: 22%(151/687) were identified as having low risk, 44% (301/687) had Int-1 risk, 4% 26/387) had Int-2, and 30% (209/687) had high risk disease. The overall incidence of thrombocytopenia (platelets <100,000/ul) across all groups was 54% (373/687) with the highest incidence being in the higher risk groups (46%), followed by Int-1 (43%) and low risk (7.5%). Of the 452 lower risk patients, 41% were thrombocytopenic (187/452). Overall, 256 lower risk patients had platelets of <150,000 and these were further divided into three subgroups based on platelet counts ranging between: 1) 100–149,000/ul; 2) 50–99,000/ul; 3) less than 50,000/ul. Median overall survival (OS) was obtained for each group. Statistical significance was calculated using Kruskal-Wallis rank sum test of equality of population. Non-thrombocytopenic lower risk patients showed a statistically significant higher median OS compared to thrombocytopenic patients (3.2 vs. 1.3 yrs p < 0.0005). Median OS progressively decreased with declining platelet range (2.4, 1.6 and 1.2 years) below 150,000/ul. Patients whose platelet counts were less than 50,000/ul had survival rates that were comparable to Int -2 patients (1.2 yrs). We conclude that the presence of thrombocytopenia predicts for poor survival in lower risk MDS patients and this information may be helpful in making therapeutic decisions.