Prognostic value of platelet recovery degree before and after achieving minimal residual disease negative complete remission in acute myeloid leukemia patients

BACKGROUND: Risk stratification and prognosis prediction of acute myeloid leukemia (AML) are largely dependent on pre-treatment information. However, post-treatment data also provides much useful information. In this retrospective study, we explored whether the level of blood count recovery before and after the first minimal residual disease (MRD) negative complete remission (CR) is relevant to clinical outcomes of AML patients. METHODS: For each included patient, peripheral platelet counts were measured on the day before initial treatment (PLT(pre)), whereas platelet peak values (PLT(peak)) were recorded after marrow recovery following the chemotherapy course inducing the first MRD-negative CR. The difference (D(PLT)) between these two values (D(PLT) = PLT(peak−)PLT(pre)) was calculated. X-tile software was utilized to establish the optimal cut-point for D(PLT), which was expected to distinguish CR patients with different clinical outcomes. A cross validation analysis was conducted to confirm the robustness of the established cut-point. The results were further tested by a Cox multivariate analysis. RESULTS: The optimal cut-point of D(PLT) was determined as 212 × 10(9)/L. Patients in high D(PLT) group were observed to have a significantly better PFS (p = 0.016) and a better OS (without statistical significance, p = 0.106). Cox multivariate analysis showed that higher D(PLT) was associated with longer PFS (HR = 2.894, 95% CI: 1.320–6.345, p = 0.008) and longer OS (HR = 3.077, 95% CI: 1.130–8.376, p = 0.028). CONCLUSION: Platelet recovery degree before and after achieving MRD-negative CR (D(PLT)) is a potential predictor of clinical outcomes in CR patients. Higher D(PLT) value is associated with longer PFS and OS. Our findings may help to develop simple methods for AML prognosis evaluation.