Factors Affecting Survival of Children with Acute Lymphoblastic Leukemia Using Competing Risks Model

Background and Objective: Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, accounting for about a quarter of all malignancies. This study aimed to identify the prognosis of patients with relapsed acute lymphoblastic leukemia in Dr. Sheikh Hospital in Mashhad from ۲۰۰۶ to ۲۰۱۵ using competing risk models. Materials and Methods: Patients with ALL from March ۲۰۰۶ to February ۲۰۱۵ were reviewed retrospectively, yielding ۴۲۴ children with acute lymphoblastic leukemia. We considered the recurrence of cancer as a main event and death without recurrence as a competing risk. We employed Cox models and sub-distributions by univariate and multivariate analysis. Data analysis was performed using Stata and R softwares. Results: The event free ۵-year survival and the overall ۵-year survival rates of all ۴۲۴ patients were ۷۰.۲% and ۸۱.۹% respectively. The ۵-year cumulative incident probability of recurrence and death prior to recurrence were ۱۲ and ۱۷ percent respectively. Based on the subdistribution models, white blood cells and blood platelets have been known to affect the recurrence of cancer. Conclusion: Our results showed that Cox and competing risk models have different results to determine the prognosis factors affecting leukemia patients’ survival despite the competing risks. Also subdistribution models reduce the duration of response to therapy and thus reduce the rate of mortality by providing significant health policies.

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Keywords: Acute lymphoblastic leukemia , Recurrence , Competing Risk , Cox , Subdistribution