Journal: Blood advances
This study evaluated whether multicolor flow cytometry (MFC)–based measurable residual disease (MRD) assessment in peripheral blood can reliably substitute for bone marrow in acute myeloid leukemia.
Key points:
- Pairwise comparison: In an initial set of 53 paired samples (30 MRD−, 23 MRD+), there was 100% qualitative concordance between peripheral blood and bone marrow MRD results, with very strong quantitative correlation (r = 0.945; P < .001).
- Prospective testing: The assay was then prospectively tested in 118 patients, including 63 in postinduction remission (both intensive and less-intensive regimens), with results cross-checked against molecular, cytogenetic, and clinical follow-up data.
- Peripheral blood MRD status across all prospective samples:
- Positive: 26
- Negative: 86
- Inadequate: 6
This corresponded to 95% sample adequacy and 98% concordance versus bone marrow.
- Diagnostic performance (using bone marrow MRD as reference):
- Sensitivity: 96%
- Specificity: 99%
- Positive predictive value: 96%
- Negative predictive value: 99%
- MRD level comparison: MRD levels were lower in peripheral blood than in bone marrow (median 0.17% vs 0.84%; P = .002), but remained significantly correlated (r = 0.6; P = .003).
- Prognostic value: Peripheral blood MRD positivity was prognostic, predicting inferior relapse-free survival both in the overall cohort (P < .01) and in the postinduction subgroup (P = .0021).
Clinical takeaway: Peripheral blood MFC-MRD testing in AML is feasible, has high concordance and predictive performance relative to bone marrow, and carries independent prognostic value for relapse-free survival, supporting its use as a practical, complementary specimen for MRD monitoring.