Prognostic factors of the five-year overall survival from childhood acute lymphoblastic leukemia: a medical record-based retrospective study

Abstract

Introduction: Acute lymphoblastic leukemia (ALL) is the most common cancer among children worldwide. Despite being a rapidly progressive malignancy, the survival from ALL has significantly improved in the recent decades from 10% in the 1960s to >90% in 2012 in resource-rich countries. However, despite major improvements in survival from ALL, many children still may have poor outcomes or even fail to survive from the disease. The prediction of the outcome depends on various prognostic factors, identifying which would help to gain insight into strategies to optimize the available treatment modalities and to improve the understanding of disease progression and the outcome. To improve the disease outcome prediction, we aimed to assess the five-year overall survival rate in the Armenian population and to identify the demographic, cytogenetic, and clinical prognostic factors of five-year overall survival for ALL among children in Armenia. Methods: We conducted a retrospective review of hospital inpatient and outpatient records of children aged 0-19 diagnosed with ALL from January 2010 – December 2014 in Armenia. The data was extracted from the records of two hospitals, namely Hematology Center after Prof. R.H. Yeolyan and the Muratsan Hospital Complex, covering the whole Armenian population during the study period. Kaplan-Meier analysis was utilized to assess the five-year overall survival rate in the population. Time-to-event analysis was conducted using Cox proportional hazard regression analysis to identify predictors of the overall survival. The log-rank test was utilized to assess the significance of the difference between the groups of the independent prognostic factors. Results: Overall, 112 ALL patients were identified during the study period. The average age at diagnosis was 6.4 years (SD = 4.8), and the male:female ratio was 1.4:1. In total, 16 patients (14%) died during the study period. The five-year overall survival rate was 82%, with a median follow-up time of 5.5 years. Our study showed the delay in diagnosis for ≥30 days was an independent predictor of the overall survival (HR=3.2, 95% CI=1.02;10.13; p<0.05) when adjusted for gender, white blood cell count at diagnosis, and splenomegaly at diagnosis. Conclusion: Our study confirms the delay in diagnosis is an independent predictor of survival. This finding designates the need for more research on determinants of patient- and physician-related delays in addition to introducing raising awareness campaigns among patients, primary health care providers, and community health workers in the rural areas to increasing awareness among the population to recognize the warning signs and symptoms of the disease. More methodologically rigorous research is needed to identify other principal prognostic factors of survival from ALL.