Minimal residual disease program for acute lymphoblastic leukemia at Dhahran Health Center

Background and Objectives: Minimal residual disease (MRD) assays for monitoring acute lymphoblastic leukemia (ALL) during treatment are defined as assays with a limit of detection of at least 0.01% leukemic blasts per mononuclear cells or total nucleated cells. Settings and Design: We retrospectively reviewed out experience at Dhahran Health Center in monitoring adult and pediatric ALL patients with a MRD assay based on immunophenotyping by flow cytometry with a level of detection of 0.01% leukemic blasts per mononuclear cells and compute Kaplan–Meier survival analysis for overall survival (OS) and relapse-free survival (RFS). We also demonstrated the incorporation of an estimated measurement uncertainty for the reported MRD values based on metrological principles. Methods: A retrospective review of all cases diagnosed with ALL from 2006 to 2012 was undertaken and after applying exclusion criteria, 26 cases were identified and patient chart review was done. Results: Although the Kaplan–Meier survival analysis for OS and RFS do demonstrate a statistically significant difference between MRD positive and negative patients, none of the pediatric ALL MRD positive cases have relapsed till now. Conclusions: The detection of MRD in ALL opens up the opportunity to intensify or alter treatment for patients with detectable levels by a highly sensitive assay before clinical relapse.