Late isolated central nervous system relapse in childhood B-cell acute lymphoblastic leukemia treated with intensified systemic therapy and delayed reduced dose cranial radiation: A report from the Children’s Oncology Group study AALL02P2

Hastings C, Chen Y, Devidas M, Ritchey AK, Winick NJ, Carroll WL, Hunger SP, Wood BL, Marcus RB, Barredo JC. Late isolated central nervous system relapse in childhood B-cell acute lymphoblastic leukemia treated with intensified systemic therapy and delayed reduced dose cranial radiation: A report from the Children’s Oncology Group study AALL02P2. Pediatr Blood Cancer. 2021 Dec;68(12):e29256. doi: 10.1002/pbc.29256. Epub 2021 Jul 24. PubMed PMID: 34302704; PubMed Central PMCID: PMC9020888.

Patients with late, ≥18 months post-diagnosis, isolated central nervous relapse (iCNS-R) of B-acute lymphoblastic leukemia (ALL) have excellent outcomes with chemotherapy plus cranial radiotherapy, with 5-yr overall survival (OS) approaching 80% in POG 9412. Subsequent relapse and radiation-related morbidity remain the causes of treatment failure and long-term sequelae. COG AALL02P2 aimed to maintain outcomes in patients with late iCNS-R using intensified chemotherapy and a decrease in cranial irradiation from 1800 to 1200 cGy. COG AALL02P2 enrolled 118 eligible patients with B-ALL and late iCNS-R who received intensified systemic therapy, triple intrathecal chemotherapy and 1200 cGy cranial irradiation delivered at 12 months, with maintenance chemotherapy continuing until 104 weeks post-diagnosis.