Minimal residual disease evaluation by flow cytometry in B cell acute lymphoblastic leukemia (BCP-ALL) and its outcome in children and adults

Objectives Acute lymphoblastic leukemia (ALL) is a most common childhood malignancy. It is a heterogeneous group of diseases with variable responses to therapy. Multiple risk factors have been identified to predict the risk of relapse and chance of cure. None of the risk factors could independently predict the relapse risk. Measurable residual disease (MRD) has emerged as an independent powerful prognostic indicator and tailor treatment accordingly to achieve higher cure rate. To evaluate the MRD status in children and adult population and analyse the outcomes between the two groups. Material and Methods A prospective study was conducted in 138 patients diagnosed with B-cell phenotype ALL (BCP-ALL). This study included all the diagnosed cases of BCP-ALL patients in whom MRD was assessed. Bone marrow examination was simultaneously performed. Results MRD positive was observed in 24% (33/138) and was negative in 76% (105/138). 5 year event free survival in MRD positive was 44.1% and 87.5% in MRD negative. Risk of disease recurrence was significantly higher in high risk group. The 5 year event free survival (EFS) based on MRD negative, MRD 0.01 to 0.1%, > 0.1 to 1% and greater than 1% was 87.5%, 41.7%, 71.4% and 0% respectively. Conclusion This is one of the few detailed reports from India in which the EFS of both adults and children treated with same protocol was studied. Study highlights the significant association of MRD status with EFS. MRD levels helps in deciding better informed clinical decisions, management and prognosis.