The Risk Factors Of Relapse During The Treatment Of Childhood Acute Lymphoblastic Leukemia

Background Acute lymphoblastic leukemia(ALL)has the highest incidence and mortality rate in childhood malignant tumor,the quality of life in children with ALL has improved significantly with continuous improvements of intensity of chemotherapy,methods and regime in the past 30 years.Although the event free survival(EFS)rate has reached 80% with appropriate treatment,there are still a number of children who failed the treatment.The causes of failure of treatment are complicated,among which relapse accounts a large proportion.The survival rate of relapsed childhood ALL was significantly lower than newly diagnosed ALL cases.Thus identifying factors that may affect the prognosis and giving corresponding treatment could improve the prognosis of childhood ALL.Objective To analyze the risk factors of relapse in childhood ALL during the treatment of children with ALL admitted in our hospital,to provide possible prognostic indicator in early stage and monitor relapse of childhood ALL more efficiently,so as to improve the cure rate.Methods All the children who were diagnosed as ALL through bone marrow cytology,flow cytometry,imunophenotyping cytogenetics and molecular biology from January 2008 to October 2017 in the pediatric ward of General Hospital of Ningxia Medical University were analyzed.A total of 161 cases who have finished chemotherapy and reached complete remission(CR)were enrolled.The study group included 32 relapsed cases and 35 non relapsed cases whose age,sex and cytogeneticpattern were corresponding to that in the study group and survived all the chemotherapy were included in the control group.The data of duration of sever myelosuppression,duration of first myelosuppression,time to CR,time of infection and common pathogens(bacteria,fungi,viruses etc)during chemotherapy were collected and analyzed with COX regression model.Results1.Relapse cases of childhood ALL: ? Relapse rate: Among 161 cases of childhood ALL in this study,32 cases relapsed during or after chemotherapy.The relapse rate was 19.9%;? Relapse sites: bone marrow(78.1%)was most common,followed by CNS(12.5%)and testis(9.4%);? Time of relapse: 14 cases of relapse occurred in very early stage(43.8%),12 in early stage(37.5%)and 6(18.7%)in late stage;?Outcome after relapse: Among 32 replased cases 26 gave up treatment,only 6 case accepted re-induction chemotherapy.Of these 5 cases,1 with CNS relapse improved and survived with intensified intrathecal therapy,4 reached second complete remission(SCR)with intensified intrathecal therapy or re-induction chemotherapy but second relapse occurred and they either gave up treatment of died,the remaining 1case did not reach SCR.2.Analysis of relapse and related risk factors in childhood ALL2.1 The average duration of sever myelosuppression was 15.0 ± 9.4 days in the study group and 9.3 ± 6.9 days in the control group with statistically significant difference(P < 0.05).2.2 The average duration of first myelosuppression was 17.3±8.6 days in the study group and 8.5 ± 4.1 days in the control group was with statistically significant difference(P < 0.05).2.3.The average time to the first CR was 22.9±10.6 days in the study group and26.5±9.3 days in control group without statistically significant difference(P> 0.05).2.4 The average cumulative infection duration was 87.9±57.7 days in the study group and,48.2 ± 21.7 days in the control group with statistically significant difference(P < 0.05).2.5 During chemotherapy,there was no significant difference in bacterial and viral infection between study group and control group(P > 0.05),but the difference of fungal infection in the two groups were statistically significant(P < 0.05).Conclusion1.The most common relapse site was bone marrow in childhood ALL,accounting for 78.1%,followed by CNS(12.5%)and testis(9.4%).2.The relapse occured more often in very early and early stages,and the prognosis was poor.3.Longer duration of severe myelosuppression,longer duration of first myelosupression in the introduction therapy,longer duration of cumulative infection,and fungal infection were regarded as risk factors closely related to childhood ALL.The time to CR,bacterial and viral infection were not closely related to relapse.