Possible risk factors associated with the CNS relapse in children with acute lymphoblastic leukemia

The Central Nervous System (CNS) is the most frequently affected extramedullary site of relapse (up to 30-40%). Importantly, study of possible risk factors associated with the CNS relapse was the purpose of this research.
In this retrospective cohort study, 159 children aged less than 15 years, diagnosed with ALL from 2008 to 2015, who are referred to Mahak Pediatric Cancer Hospital and Research Center, chosen by convenient sampling and afterwards their information were recorded. Data analysis done by using SPSS software version 16; at first, statistics were described using the mean and standard deviation. Then, we did Log-rank test and Kaplan-Mayer analysis to compare the proportions. Survival analysis model helped us to discuss about the relapse rate.
Among children in the study, 56.6% are male with the average age of 5.33 years. The CNS relapse occurred in 19 patients (11.9%). In the first lumbar puncture (LP) done for diagnostic approach, 24 patients (15.09%) got traumatized. However, there was no significant deference between these patients and the other group with clean puncture (P = 0.961).The majority of relapses (68.42%) were in patients with no cytogenetic abnormalities. In Log-rank test there was no proof to support the age related CNS relapse (P=0.197). The average and standard deviation of life long after treatment was in order 480.66 and 21.04 days in males and 480.20 and 10.58 days in females(P=0.030).
Boy sex is a risk factor for CNS relapse in ALL. Traumatized lumbar puncture would remove from the risk factors in contrast to some other studies according to our research. Finally, considering the previous studies, more researches with greater population is recommended.