Posterior Reversible Encephalopathy Syndrome: Risk Factors and Impact on the Outcome in Children With Acute Lymphoblastic Leukemia Treated With Nordic Protocols

Posterior reversible encephalopathy syndrome (PRES) in children with acute lymphoblastic leukemia has been increasingly recognized as a clinicoradiological entity. Our aim was to describe the incidence of PRES in pediatric patients with ALL, identify its risk factors, and examine its prognostic importance. For this research, we conducted a systematic, retrospective review of the patient records in a population-based series of children with acute lymphoblastic leukemia (n = 643) treated in Finland from 1992 to 2008. Of the patients with ALL, 4.5% (n = 29) developed radiologically confirmed PRES, of which 28 cases occurred during induction. Hypertension (P = 0.006; odds ratio [OR], 4.10, confidence interval [CI], 1.50-11.25), constipation (P = 0.001; OR, 5.60; CI, 2.02-15.52), and > 14 days of alkalinization (P = 0.017; OR, 3.27; CI, 1.23-8.68) were significant independent risk factors for PRES. One-third of the patients developed epilepsy. Relapses occurred significantly more often in those patients with PRES (P = 0.001), which was associated with worse overall survival (P = 0.040; 5-year survival = 75.9% [60.3%-91.4%] vs. 88.4% [85.8%-90.9%]). Using NOPHO-ALL 92/2000 protocols, PRES is a significant early complication of therapy in ALL, and was associated with a poorer prognosis and significant neurological morbidity.