A simplified minimal residual disease polymerase chain reaction method at early treatment points can stratify children with acute lymphoblastic leukemia into good and poor outcome groups

Abstract

The online version of this article contains a supplementary appendix. BackgroundMinimal residual disease is an important independent prognostic factor in childhood acute lymphoblastic leukemia. The classical detection methods such as multiparameter flow cytometry and real-time quantitative polymerase chain reaction analysis are expensive, time-consuming and complex, and require considerable technical expertise. Design and MethodsWe analyzed 229 consecutive children with acute lymphoblastic leukemia treated according to the GBTLI-99 protocol at three different Brazilian centers. Minimal residual disease was analyzed in bone marrow samples at diagnosis and on days 14 and 28 by conventional homo/heteroduplex polymerase chain reaction using a simplified approach with consensus primers for IG and TCR gene rearrangements. ResultsAt least one marker was detected by polymerase chain reaction in 96.4% of the patients. By combining the minimal residual disease results obtained on days 14 and 28, three different prognostic groups were identified: minimal residual disease negative on days 14 and 28, positive on day 14/negative on day 28, and positive on both. Five-year event-free survival rates were 85%, 75.6%, and 27.8%, respectively (p<0.0001). The same pattern of stratification held true for the group of intensively treated children. When analyzed in other subgroups of patients such as those at standard and high risk at diagnosis, those with positive B-derived CD10, patients positive for the TEL/AML1 transcript, and patients in morphological remission on a day 28 marrow, the event-free survival rate was found to be significantly lower in patients with positive minimal residual disease on day 28. Multivariate analysis demonstrated that the detection of minimal residual disease on day 28 is the most significant prognostic factor. ConclusionsThis simplified strategy for detection of minimal residual disease was feasible, reproducible, cheaper and simpler when compared with other methods, and allowed powerful discrimination between children with acute lymphoblastic leukemia with a good and poor outcome.

Initial Diagnostic Workup of Acute Leukemia: Guideline From the College of American Pathologists and the American Society of Hematology

“…ALL children 1 to 9 years old generally had a morefavorable outcome than those younger than 1 or older than 10 years, 17,22,27,34,36 whereas, in AML, patients 60 years old or older have worse outcomes compared to younger patients. Published evidence revealed that sex was also prognostically important.…”

“…Most of the PCSs had a risk of bias determination of low to moderate, except for 3 studies determined to be low 12,24,30 and 6 determined to be moderate. 14,22,26,29,32,33 None of those studies were found to have methodological flaws that would raise concerns about the studies' findings. Refer to Supplemental Table 7 in the SDC for the quality-assessment results for the studies included for statement 1.…”

“…19,20,22,91 In a study of 4959 noninfant patients with Bprecursor ALL treated between 1986 and 1999 by various protocols, patients having CNS disease at presentation were associated with poor outcomes in a multivariate analysis (hazard ratio [HR], 1.34; P ¼ .04). 19 A Nordic study of 2668 children with ALL, who were treated in 2 successive trials between 1992 and 2007, showed a significantly increased risk of treatment failure (P , .01 in both study cohorts) if CNS disease (defined as !5 3 10 3 /mm 3 leukemic cells in the diagnostic spinal tap) was present at presentation.…”

“…19,20,22,91 One study was deemed to have a low risk of bias, 91 2 were deemed to have a low to moderate risk, 19,20 and one was deemed to have a moderate risk of bias. 22 None of those studies were found to have methodological flaws that would raise concerns about the studies' findings.…”

“…20 A Brazilian study of 229 consecutive children with ALL treated with a single protocol, for whom 220 were evaluable for CNS status at presentation, reported a statistically significant difference (P , .001) in 5-year EFS between children with (n ¼ 9; 5-year EFS mean [SD], 79.4% 6 3.1) and without (n ¼ 211; 5-year EFS mean [SD], 40% 6 17.4) CNS involvement. 22 Refer to Supplemental Table 8 for the quality-assessment results of included studies for statement 2.…”