Immature platelet fraction predicts early marrow recovery after severe chemotherapy associated neutropenia

Febrile neutropenia secondary to chemotherapy is one of the most critical complications in cancer treatment. The aim of this study was to determine if an increase in the percentage of immature platelet fraction (IPF%) might predict early neutrophil recovery following cytostatic-dependent aplasia. A retrospective cohort study compared serial complete blood counts and the level of C-reactive protein (CRP) following induction chemotherapy for Ewing sarcoma and Non-Ewing sarcoma patients. The measurements were taken on a Sysmex XE-2100 instrument. A total of 287 paired samples from 28 children after the first cycle of chemotherapy were analyzed to test if an increase in the IPF% anticipated the CRP peak and recovery of neutrophil count. The chemotherapy associated nadir of neutrophils, reticulocytes and platelets was reached at 9.7 ± 1.5, 11.0 ± 1.7 and 11.9 ± 0.9 days (mean ± SD) respectively, in Ewing sarcoma patients. Still in severe neutropenia, IPF% was the first parameter that significantly increased and anticipated the CRP peak (11.9 ± 1.6 days, mean ± SD). The IPF% continuously increased (maximum = 6.56% ± 2.8%, mean ± SD) and peaked at 12.2 ± 1.4 days (mean ± SD) after commencement of chemotherapy. Compared to neutrophil recovery (14.6 ± 1.4 days, mean ± SD), the IPF% peak was anticipated by 2.4 days (p = 0.0085). Although variably treated, in non-Ewing sarcoma patients the effect was similar and the IPF% peak anticipated neutrophil recovery by 6.8 ± 4.7 days (p < 0.01). IPF% increased significantly at > 48 h before neutrophil recovery in patients treated with chemotherapy. IPF% is an inexpensive parameter and may be valuable in the management of febrile neutropenia.