The Clinical Characteristics Of Extramedullary Infiltration In Acute Myeloid Leukemia

BackgroundThe clinical manifestations of acute myeloid leukemia(AML)are mainly the inhibition of normal hematopoietic marrow and the extramedullary infiltration(EMI)of leukemia cells.In AML,EMI mainly refers to central nervous system leukemia(CNSL),leukemia cutis(LC)and myeloid sarcoma(MS).Extramedullary lesions of AML can occur in any organ.It may be primary manifestation of AML without evidence of leukemia in the bone marrow which was termed as primary extramedullary,it also may coexist with changes in the bone marrow,or may be an independent lesion during recurrence.The prognosis of AML with CNSL is poor,while the effect of extramedullary diseases in other tissues on the prognosis of AML is not clear.Although it is generally believed in clinical that AML patients with EMI have a poor prognosis,current research results show that the influence of EMI on the prognosis is still controversial,and more clinical studies are needed to further clarify.ObjectiveThe clinical and disease characteristics of AML with EMI patients were studied,and their survival and possible risk factors were analyzed.Methods1.Fifty-nine patients with AML combined with EMI who were diagnosed in The Affiliated Cancer Hospital of Zhengzhou University and The First Affiliated Hospital of Henan University of Science and Technology from June 2012 to May 2019 were collected as the study subjects.2.The clinical characteristics,disease characteristics and treatment were analyzed,and the prognosis of the subjects was followed up by referring to the medical records or contacting by telephone.The follow-up deadline was December 1,2019.3.The starting point of the study was the date of bone marrow puncture or biopsy at the time of diagnosis,and the end point was the death of the subjects.OS is defined as the time from the starting point to the end point or the follow-up deadline,and the OS after the occurrence of EMI is defined as the time from the detection of EMI to the end point or follow-up deadline,all lost patients to the nearest survival time.4.IBM SPSS Statistics 22 software was used for statistical analysis.In each group,independent sample t-test or rank sum test was used for the comparison of continuous variables,chi-square test was used for the comparison of rates,and Kaplan-Meier method was used for the analysis of survival.The significance test level was 0.05,and P<0.05 was considered to be statistically significant.Results1.Among the 59 patients of AML combined with EMI,36 were males and 23 were females,with a male-female ratio of 1.6:1 and a median age of 36(5-69)years.The proportion of M2 patients was higher(44.1%),and the t(8;21)was the common chromosome abnormality.Sexual chromosome deletions were common in patients with t(8;21),and abnormal expression of CD56 occurs frequently(43.5%).The most common site of MS was subcutaneous soft tissue(23.7%).At the end of the follow-up,34 patients(57.6%)had reached the end point,20 patients(33.9%)survived,and 5 patients(8.5%)lost to follow-up.The median follow-up time was 22(1-120)months.2.The CR rate of 50 patients with one course of treatment was 62%,and that of 47 patients with two courses of treatment was 83.0%.There was no significant difference in CR rates between de novo EMI patients and secondary EMI patients(P=0.742).3.There were no significant difference between CNSL patients and MS patients in gender composition,age distribution,leucocyte levels at initial diagnosis,cytogenetics and molecular genetics prognosis(P>0.05).There were significant differences between the two disease subtypes--the majority of MS patients were subtypes M2 and M5,and M3 was less(P=0.001).4.There were 35 patients(59.3%)with de novo EMI,with a median OS of 30 months,and 24 patients(40.7%)with secondary EMI,with a median OS of 24 months.There was no statistically significant difference between the two groups(P=O.620).After the occurrence of EMI,the median OS of the former was 30 months,while the latter was 7 months,which was significantly shorter than the former(P=0.007).5.The median OS of MS patients was shorter than that of CNSL patients,and the differences were not statistically significant.6.There were 20 CD56+AML patients(43.5%),with a median OS of 22 months,and 26 CD56-AML patients(56.5%),with a median OS of 51 months.There was no statistically significant difference between the two groups(P=0.192).7.Among the MS patients,34 patients(76.7%)appeared a single lesion,with the median OS of 30 months,and 10 patients(23.3%)appeared multiple lesions,with the median OS of 18 months.There was no statistically significant difference between the two groups(P=0.277).Conclusion1.The CR rate of patients with AML combined with EMI is not low(the CR rate was 62%in one course of treatment and 83.0%in two courses of treatment).t(8;21)and abnormal expression of CD56 were more common in such patients.2.The most common site of MS was subcutaneous soft tissue.3.Patiens with AML would have shorter survival time after secondary EMI.4.The OS of MS patients was shorter than that in CNSL patients,the OS of patients with secondary EMI was shorter than that of patients with de novo EMI,the OS of CD56+patients was shorter than that of CD56-patients,and the OS of MS patients with multiple lesions was shorter than that of MS patients with a single lesion,but none of the differences were statistically significant.