What happens to children with acute lymphoblastic leukemia in low- and middle-income countries after relapse? A single-center experience from India

Managing a child with acute lymphoblastic leukemia (ALL) after relapse is arduous in low- and middle-income countries. A file review of children aged ≤15 years diagnosed with relapsed ALL from 2010 to 2019 was performed. Classification of relapse followed the Berlin-Frankfurt-Münster (BFM) scheme. The majority of patients were treated with a modified ALL-REZ-BFM protocol. Of 764 children treated for ALL in the study period, 163 (21.3%) relapsed. The median age at relapse was 101 months (range: 8-297). The immunophenotype was B-ALL and T-ALL in 140 (86%) and 23 (14%) patients. The site of relapse was extramedullary, combined, and medullary in 46 (28%), 45 (28%), and 72 (44%) patients. Very early, early, and late relapses were observed in 57 (35%), 66 (40%), and 40 (25%) patients. The proportions of extramedullary and medullary sites were greater among patients with early and late relapses, respectively (p = 0.039). Eighty-four (52%) patients were treated with palliative intent. The 2-year event-free survival (EFS) of patients treated with curative intent was 36.3 ± 6.3%. The 2-year EFS for very early/early and late relapses were 18.2 ± 6.2% and 67.6 ± 10.4% (p < 0.001). The 2-year EFS did not differ between extramedullary, combined, and medullary relapses. Treatment-related mortality occurred in 14 (20%) patients. More than 50% of the patients with relapse were treated with the intent of palliation. Extramedullary relapses were more likely to be early and did not have a better outcome than medullary relapses. Children with late relapse had a fair chance of survival with chemotherapy.