Clinical value of the quantitation of average daily platelet increase during the recovery period in childhood acute lymphoblastic leukaemia

The time to platelet recovery (TPR) is becoming a predicting factor during the treatment of childhood acute leukaemia. However, the initial pre-treatment platelet count (PPC) could interfere with TPR. Here, we integrated both TPR and PPC as the average daily platelet amount increase (Ap) to predict the prognosis in childhood B-ALL during the recovery period.148 patients were enrolled. The relationship between the Ap and MRD was evaluated, and Multivariate analysis was performed to evaluate whether Ap was independently associated with a better EFS. The PPC was inversely correlated with TPR (rs = -0.519, P = 0.021). Patients in Ap >3.9 × 10⁹/L group had better EFS (x² = 3.109, P = 0.028) than TPR ≤ 16d. Multivariate analysis indicated that Ap > 3.9 × 10⁹/L was independently associated with a longer EFS (RR = 3.468; 95%CI: 1.037-11.597, P = 0.043). However, when introducing both MRD and Ap > 3.9 × 10⁹/L as candidate variables, the Ap > 3.9 × 10⁹/L lost its independent effect (P = 0.081). The strong association between MRD on treatment day 33 and Ap > 3.9 × 10⁹/L (x² = 148.00, P = 0.000) was responsible for this phenomenon. Ap could be a valuable prognostic indicator in childhood B-ALL.