Complete Peripheral Blast Clearance is Superior to the Conventional Cut-Off of 1000/µL in Predicting Relapse in Pediatric Pre-B Acute Lymphoblastic Leukemia

• Published in: Indian journal of hematology & blood transfusion Vol. 37; no. 3; pp. 366 - 371
• Main Authors: Cherian, Thomas, John, Rikki, Joseph, Leenu Lizbeth, Srinivasan, Hema N., Boddu, Deepthi, Geevar, Tulasi, Mathew, Leni Grace, Totadri, Sidharth
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.07.2021; Springer Nature B.V
• Subjects: Blood Transfusion Medicine; Blood transfusions; Bone marrow; Hematology; Human Genetics; Leukemia; Medical prognosis; Medicine; Medicine & Public Health; Oncology; Original; Original Article; Pediatrics; Childhood leukemia; Poor prednisolone response; Early bone marrow; Prognostic marker; Rapid early response
• ISSN: 0971-4502; 0974-0449; 0974-0449; 0971-4502
• DOI: 10.1007/s12288-020-01354-0

Risk-stratification has contributed to a dramatic improvement in survival in pediatric acute lymphoblastic leukemia (ALL). This study evaluated the utility of prephase response and day 15 bone marrow when a minimal residual disease (MRD) assessment was available. A file review of children aged ≤ 15 years diagnosed with precursor-B ALL from 2014 to 2019 was performed. The protocol used for risk stratification and treatment was based on a UKALL-2003 backbone. All patients received one week of prephase therapy comprised of intravenous dexamethasone in the first 48 h followed by oral prednisolone. The median age of the 255 patients in the study was 5 years. Following the prephase, the peripheral blood absolute blast count was 0 and ≥ 1000/µL blasts in 141 (56%) and 29 (11%), respectively. Ten of 199 (5%) patients with an evaluable day 15 bone marrow had M3 status. At the end of induction, 30 (12%), 127 (50%) and 98 (38%) patients belonged to the standard-risk, intermediate-risk and high-risk (HR) groups, respectively. An M3 day15 bone marrow was the sole reason for escalation in three (3%) of the patients in the HR group. A lack of complete clearance of peripheral blood blasts post-prephase [HR: 2.45 (1.04–5.75), p  = 0.040] and a positive MRD [HR: 3.00 (1.28–7.02), p = 0.011] independently predicted risk of relapse. Complete blast clearance is superior to the traditional cut-off of 1000/µL in predicting relapse. The role of a day 15 bone marrow morphology is diminished when an end of induction MRD is available.