The Relationship Between Speed Of Platelet Recovery And Its R-squared And Efficacy After First Induction Chemotherapy In Acute Myeloid Leukemia

Objective:The platelet counts in peripheral blood of patients with acute myeloid leukemia(AML)after initial chemotherapy were collected,and the growth rate(recovery speed)of platelet counts was analyzed by linear regression equation.At the same time,the fit degree(the R-squared,R~2)of these linear regression equations was recorded.By finding the threshold value of platelet recovery rate and linear fitting degree after initial induction chemotherapy,it can be used to evaluate the response of AML patients to chemotherapy drugs after initial induction chemotherapy,which may guide clinicians to select the appropriate treatment plan for the next step as soon as possible.Methods:A retrospective analysis was performed on 117 patients with newly diagnosed AML who received induction chemotherapy at the Second Hospital of Shanxi Medical University.Upon admission,flow cytometry,real-time quantitative PCR(RQ-PCR)and gene sequencing were used to determine the cytogenetic and molecular changes and identify the risk stratification.After the first induction chemotherapy,peripheral blood platelet count was detected for 5 consecutive times from the lowest count to discharge,and the recovery speed of platelet count and its linear fit degree R~2 were calculated.Meanwhile,after the first induction chemotherapy,the patient underwent bone marrow aspiration at the Second Hospital of Shanxi Medical University to evaluate the remission of bone marrow.According to the results of calculating 5 consecutive peripheral blood plate counts,AML patients enrolled in this study were divided into a high-speed response group,a low-speed response group,a high linear fit group and a low linear fit group.The cut off value between the recovery speed of peripheral blood plate and the linear fit degree was obtained by ROC curve calculation and analysis.χ2 test was used to observe whether there was a statistical difference in the effect of first induction chemotherapy among all groups,and whether it was consistent with the judgment result after bone marrow aspiration.Results:There were 71 males(60.68%)and 46 females(39.32%)enrolled in the study,with a median age of 53(41-63)years at first diagnosis.In the risk stratification of AML,there were 17 cases(14.533%)in the low risk group,24 cases(20.51%)in the medium risk group,and 76 cases(64.96%)in the high risk group.The median platelet recovery speed in this group(enrolled patients)was 5.91(1.44-15.19)×10~9/L·day,and the median linear fit R~2 was 73%(34%-87%).The platelet recovery speed of patients in remission group after the first induction chemotherapy was 10.90(4.07-21.78)×10~9/(L·day),while that of patients in non-remission group was 3.23(0.74-7.78)×10~9/(L·day),and there was statistical difference between them(P<0.001).The linear fit value R~2 of the linear regression equation of peripheral platelet counts for five consecutive times in the remission group was 79.6%(47%-90.6%),and the linear fit value R~2 of the non-remission group was 54.6%(14.5%-79.4%),with statistical difference(P=0.001).Using ROC curve analysis,the cut-off value of platelet recovery rate and its linear fit value R~2 of the first induction chemotherapy to achieve remission was 4.0595×10~9/(L·d)and 72.7%,the sensitivity was 77%and 63.9%,the specificity was 62.5%and67.9%,and the Youden index was 0.395 and 0.318,respectively.According to the above cut-off values,patients were divided into the high speed response group A(recovery speed≥4.0595×10~9/(L·day)),the low speed response group B(recovery speed<4.0595×10~9/(L·day)),the higher linear fit R~2 group(R~2≥72.67%)and the lower linear fit R~2 group(R~2<72.67%).χ2 test was used to compare the remission of the two groups,and there was a statistical difference between them(P<0.0001,P=0.001).Conclusion:Using peripheral platelet count and ROC curve,the cut-off value of platelet recovery speed and its R~2 after the first induction chemotherapy was calculated the patients with AML.For newly diagnosed AML patients receiving standard induction chemotherapy,the faster the platelet recovery speed after chemotherapy,the more likely the patient is to achieve remission,and the more stable the platelet growth trend(R~2)during recovery,the more likely the patient is to achieve remission.