The role of minimal residual disease in therapy of pediatric acute lymphoblastic leukemia: a prospective cohort study

Background. During last 50 years there was a significant progress in understanding the nature of pediatric acute lymphoblastic leukemia (ALL). There were developed effective chemoradiotherapy regimens, new methods of diagnosis and emerged evaluation of treatment results. Determination of minimal residual disease (MRD) has become the most important factor in the patient’s stratification for risk-adapted treatment in the ALL IC-BFM 2009.

Aim. To evaluate the survival rates of children with ALL according to the ALL IC-BFM 2009 protocol.

Materials and methods. There were 136 people in the study of evaluating the effectiveness of therapy according to the ALL IC-BFM 2009 protocol: 69 boys and 67 girls (ratio 1.03:1). The median age is 4 years and 10 months. The observation period is from 26.01.2010 to 06.11.2022.

Results. High survival rates of children with newly diagnosed ALL are achieved: overall survival (OS) is 91.2%, event-free (EFS) – 82.4%, relapse-free (RFS) – 88.6%. The best results are among patients of the standard risk group: OS, EFS and RFS reach 96.6%. In the intermediate group OS – 96.2%, EFS – 84.8% and RFS – 88.3%. Worse results of survival are in the high risk group: OS – 76.9%, EFS – 65.4% and RFS – 80.7%. Outcome analysis depending on the linear reveals a statistically insignificant difference in survival rates (for B-ALL OS – 92.4%, EFS – 83.1% and RFS – 89.5%, for T-ALL OS – 83.3%, EFS – 77.8% and RFS – 83.3%). It determines the tendency of improving the prognosis of pediatric T-ALL by optimizing the stratification of patients based on the indicators of MRD and the best direction of protocol.

Conclusion. Results of survival rates of patients with ALL confirm high effectiveness of treatment according to the ALL IC-BFM 2009 protocol. MRD level on day 15 makes it possible to stratify patients and choose the optimal risk-adapted therapy.