Minimal Residual Disease in Adult Acute Lymphoblastic Leukemia: Egyptian Experience

BACKGROUND: Acute lymphoblastic leukemia (ALL) is a clonal disease that affects early lymphoid progenitors in the bone marrow. Minimal residual disease (MRD) is assessed by different methods to monitor disease kinetics after treatment. AIM: to Assess MRD post-induction, at 6 and 12 months after intensive chemotherapy in adult patients with ALL. Patients and Methods: Seventy adult newly diagnosed acute lymphoblastic leukaemia patients were enrolled between July 2018 and July 2019 at the Clinical Hematology Unit, Ain Shams University hospitals, Egypt. MRD was assessed on the bone marrow samples using multi-parameter four color flow cytometry with 0.01% cut-off; below which cases are deemed MRD negative. RESULTS: After the end of induction period, 13 out of 46 patients (28%) had positive MRD. However, MRD positivity is demonstrable in 14/32(43.8%), and 10/28(35.7%) patients at 6 and 12 months; respectively. MRD positivity was significantly associated with older age group (more than 39 years) and high NCCN risk stratum with p-values <0.05. Moreover, most of MRD positive patients at 12 months of therapy were of T-ALL immunophenotype (P value 0.002). Patients with complete remission and negative MRD exhibited significantly higher overall survival when compared to patients having MRD positivity (P value 0.027). CONCLUSION: MRD is a powerful predictor of outcome in ALL and its positivity at different time points is associated with poor prognostic factors as well as survival outcomes.