Incidence and survival of pediatric low-grade gliomas in Switzerland

BACKGROUND: Brain tumors are the most common solid cancers occurring in children, with pediatric low-grade gliomas (pLGG) being the most frequent central nervous system (CNS) tumors in children. The overall survival of pLGG is excellent, with a ten-year survival of 85%-96%. Prognostic factors include age, gender, anatomical location, and histological and molecular subtype. Despite the excellent survival rates, children suffering from pLGG often have a diminished quality of life due to functional or neurologic deficits either caused by the primary tumor or as a side effect of their treatment. In this study, we describe the epidemiology of pLGG in Switzerland. METHODS: The target population comprised children aged 0-17 years, diagnosed with histologically verified pLGG during 1990-2019 while residing in Switzerland. We retrieved the data from the Swiss Childhood Cancer Registry (ChCR). We calculated crude incidence rates per 100,000 person-years and observed survival (OS) using the Kaplan-Meier estimator (non-parametric univariable analysis). We estimated OS separately according to age histological subgroup and treatment group. RESULTS: We included 591 pLGG during 1990-2019 in Switzerland. Most pLGG were diagnosed at the age of 2-11 years (n = 352, 59.6%). Around half of pLGG were supratentorial located (n = 286, 48.4%), while the other half (n = 266, 45.0%) occurred infratentorial. Most pLGG (82.0%) were World Health Organization (WHO) grade 1. The vast majority of pLGG (n = 501, 84.8%) were treated with surgery, either alone (n = 441, 74.6%) or in combination with other treatments. The lowest 5- and 10-year survival was observed in children who received surgery followed by radiotherapy and/or chemotherapy (40% and 20%). Astrocytoma excluding pilocytic astrocytoma had a significantly lower 5-year, 10-year and total survival (98.8%, 85.8%, and 82.1%) compared to the other histopathological subtypes (P = 0.024). CONCLUSIONS: This is the first report on the incidence and survival of children with pLGG in Switzerland. Children with pLGG have an excellent long-term survival rate of over 90%.