Clinical Significance Of Peripheral Blast Clearance Rate In The Evaluation Of Treatment Response And Prognosis Of Patients With Acute Myeloid Leukemia

Background:Minimal residual disease detection in the bone marrow is usually performed in patients with acute myeloid leukemia undergoing one course of induction chemotherapy.To optimize the chemotherapy strategies during induction,more practical and sensitive markers are needed to monitor the early treatment response.Therefore,the monitoring of residual peripheral blood blast cells after chemotherapy may be considered as an ideal monitoring marker.Methods: PB blasts were monitored through multiparameter flow cytometry(MFC).Absolute counts were determined before treatment(D0)and at specified time points of induction chemotherapy(D3,D5,D7,and D9).The cut-off value of D5 peripheral blast clearance rate(D5-PBCR)was defined through receiver operating characteristic(ROC)analysis.Prognostic effects were compared among different patient groups according to D5-PBCR cut-off value.Results: D5-PBCR cut-off value was determined as 99.55%.Prognostic analysis showed that patients with D5-PBCR?99.55% more likely achieved complete remission(91.9% vs.59.6%,P=0.001).For survival analysis,patients with D5-PBCR?99.55% showed prolonged overall survival(twoyear OS: 61.2% vs.43.3%,P=0.007).In cytogenetic-molecular intermediate-risk group,a subgroup with worse outcome could be distinguished by D5-PBCR<99.55%(two-year OS: 71.6% vs.39.4%,P=0.036).In multivariate analysis,D5-PBCR,cytogenetic-molecular risk stratification and hematopoietic stem cell transplantation status are all listed as independent risk factor of OS.Conclusions: An effective evaluation method of early treatment response was established by monitoring PB blasts through MFC.D5-PBCR cut-off value(99.55%)can be a reliable reference to predict treatment response and outcome in early stages of chemotherapy.The proposed marker may help optimize cytogenetic-molecular prognostic risk stratification.And D5-PBCR may act as the basis for a precision and individualized induction regimen modification treatment strategy.