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- 2018
Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemiaDOI: https://doi.org/10.1038/s41375-018-0307-6 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
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