The French FRACTURE database: A way to improve knowledge on management of children with very rare tumors.

INTRODUCTION: Very rare pediatric tumors (VRTs), defined by an annual incidence ≤2 per million inhabitants, represent a heterogeneous group of cancers. Due to their extremely low incidence, knowledge on these tumors is scant. Since 2012, the French Very Rare Tumors Committee (FRACTURE) database has recorded clinical data about VRTs in France. This study aims: (a) to describe the tumors registered in the FRACTURE database; and (b) to compare these data with those registered in the French National Registry of Childhood Cancer (RNCE). METHODS: Data recorded in the FRACTURE database between January 1, 2012 and December 31, 2018 were analyzed. In addition, these data were compared with those of the RNCE database between 2012 and 2015 to evaluate the completeness of the documentation and understand any discrepancies. RESULTS: A total of 477 patients with VRTs were registered in the FRACTURE database, representing 97 histological types. Of the 14 most common tumors registered in the RNCE (772 patients), only 19% were also registered in the FRACTURE database. Total 39% of children and adolescent VRTs registered in the RNCE and/or FRACTURE database (323 of a total of 828 patients) were not treated in or linked to a specialized pediatric oncology unit. CONCLUSION: VRTs represent many different heterogenous entities, which nevertheless account for 10% of all pediatric cancers diagnosed each year. Sustainability in the collection of these rare tumor cases is therefore important, and a regular systematic collaboration between the FRACTURE database and the RNCE register helps to provide a more exhaustive picture of these VRTs and allow research completeness for some peculiar groups of patients.