On the basis of the results of previous national and international trials and studies, the
Renal Tumour Study Group of the International Society of Paediatric Oncology (SIOP–RTSG) has
developed a new study protocol for paediatric renal tumours: the UMBRELLA SIOP–RTSG 2016
protocol (the UMBRELLA protocol). Currently, the overall outcomes of patients with Wilms
tumour are excellent, but subgroups with poor prognosis and increased relapse rates still exist.
The identification of these subgroups is of utmost importance to improve treatment stratification,
which might lead to reduction of the direct and late effects of chemotherapy. The UMBRELLA
protocol aims to validate new prognostic factors, such as blastemal tumour volume and molecular
markers, to further improve outcome. To achieve this aim, large, international, high-quality
databases are needed, which dictate optimization and international harmonization of specimen
handling and comprehensive sampling of biological material, refine definitions and improve
logistics for expert review. To promote broad implementation of the UMBRELLA protocol, the
updated SIOP–RTSG pathology and molecular biology protocol for Wilms tumours has been
outlined, which is a consensus from the SIOP–RTSG pathology panel