Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemia

Leukemia. 2019 Jun;33(6):1324-1336. doi: 10.1038/s41375-018-0307-6. Epub 2018 Dec 14.

Abstract

Minimal residual disease (MRD) measured by PCR of clonal IgH/TCR rearrangements predicts relapse in T-cell acute lymphoblastic leukemia (T-ALL) and serves as risk stratification tool. Since 10% of patients have no suitable PCR-marker, we evaluated flowcytometry (FCM)-based MRD for risk stratification. We included 274 T-ALL patients treated in the NOPHO-ALL2008 protocol. MRD was measured by six-color FCM and real-time quantitative PCR. Day 29 PCR-MRD (cut-off 10-3) was used for risk stratification. At diagnosis, 93% had an FCM-marker for MRD monitoring, 84% a PCR-marker, and 99.3% (272/274) had a marker when combining the two. Adjusted for age and WBC, the hazard ratio for relapse was 3.55 (95% CI 1.4-9.0, p = 0.008) for day 29 FCM-MRD ≥ 10-3 and 5.6 (95% CI 2.0-16, p = 0.001) for PCR-MRD ≥ 10-3 compared with MRD < 10-3. Patients stratified to intermediate-risk therapy on day 29 with MRD 10-4-<10-3 had a 5-year event-free survival similar to intermediate-risk patients with MRD < 10-4 or undetectable, regardless of method for monitoring. Patients with day 15 FCM-MRD < 10-4 had a cumulative incidence of relapse of 2.3% (95% CI 0-6.8, n = 59). Thus, FCM-MRD allows early identification of patients eligible for reduced intensity therapy, but this needs further studies. In conclusion, FCM-MRD provides reliable risk prediction for T-ALL and can be used for stratification when no PCR-marker is available.

MeSH terms

  • Adolescent
  • Adult
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Child
  • Child, Preschool
  • Female
  • Flow Cytometry / methods*
  • Follow-Up Studies
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / drug therapy
  • Neoplasm Recurrence, Local / pathology*
  • Neoplasm, Residual / diagnosis*
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / drug therapy
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / pathology*
  • Prognosis
  • Risk Assessment / methods*
  • Survival Rate
  • Young Adult