[Clinical Characteristics and Prognosis of Children with Relapsed Acute Lymphoblastic Leukemia]

To investigate the clinical characteristics and prognosis of children with relapsed acute lymphoblastic leukemia (ALL).

The clinical data of 55 children who were diagnosed with ALL and relapsed after regular chemotherapy in the Children's Hospital Affiliated to Kunming Medical University from January 2016 to December 2023 were collected, and the relationship between different recurrence time, recurrence site and prognosis was analyzed.

Among the 55 recurrent children, 25 cases had very early recurrence, 14 cases had early recurrence, and 16 cases had late recurrence. The remission rate of d19 MRD and d46 MRD in children with very early recurrence was 80.0% and 92.0%, in children with early recurrence was 85.7% and 92.9%, and in children with late recurrence was 68.8% and 100%, respectively. There were 44 cases of isolated bone marrow relapse, 1 case of isolated central nervous system relapse, 1 case of isolated testicular relapse, and 9 cases of combined relapse, including 3 cases of bone marrow combined with central nervous system recurrence, 5 cases of bone marrow combined with testicular recurrence, and 1 case of bone marrow combined with central nervous system and testicular recurrence. The remission rates of d19 MRD and d46 MRD in children with isolated bone marrow relapse were 72.7% and 93.2%, respectively, in children with isolated extramedullary relapse they were both 100%, and in children with bone marrow combined with extramedullary relapse they were also both 100%. The symptoms of relapsed children included fever in 28 cases, pallor in 24 cases, lymphadenopathy in 14 cases, bone pain in 13 cases, cough in 11 cases, petechia in 11 cases, vomiting in 6 cases, liver and/or spleen enlargement in 3 cases. The follow-up was conducted until March 31, 2024, the median survival time of all relapsed children was 5 months. The median survival time of children with very early recurrence, early recurrence and late recurrence was 5 months, 2 months and 9 months, respectively (P < 0.05). The median survival time of children with isolated bone marrow relapse, isolated extramedullary relapse and combined relapse was 5 months, 5 months and 4 months, respectively (P >0.05). The median survival time of relapsed children in high-risk group, intermediate-risk group and low-risk group was 2 months, 5 months and 5 months, respectively.

Fever and pallor at initial diagnosis are the main symptoms of ALL recurrence, but they are not specific. The recurrence time is very early, and the prognosis of early recurrence is poor. The main site of recurrence is bone marrow, and the prognosis of combined recurrence is poor. BCR-ABL⁺ children are common and prone to occur very early recurrence and bone marrow recurrence.