Chemotherapy delays in children with acute lymphoblastic leukemia might influence the outcome of treatment

Acute Lymphoblastic Leukemia (ALL) is one of the most commonly occurring cancers among children with one of the highest survival rates, thanks to its very strict treatment protocol. In this paper, the impact of delays in treatment during the induction phase was assessed. Retrospective single center analysis of 127 patients treated between years 2003 and 2015 was performed. Patients were categorized by their respective gender, age, leukemia variant, risk group and chemotherapy protocol used. The delays were measured using protocol milestones as reference points. The associations between treatment delay intervals and event-free survival (PFS) or overall survival (OS) were evaluated using Kaplan-Meier curves and univariate Cox proportional hazards regression models. Delays in treatment which occurred before the 8th day were associated with a 30% increase in the risk of death (p<0.01) and a 33% increase in the risk of relapse or death (p<0.01). The influence of delays after the 8th day was statistically insignificant. Delays were proven to have the most influence on outcome in the high-risk group, especially before the 8th day. The ALL treatment protocols should be strictly followed as any delay may lead to worse patients’ survival.