Since 1971 SIOP (International Society of Paediatric Oncology) has conducted 7 prospective clinical trials (SIOP 1, SIOP 2, SIOP 5, SIOP 6, SIOP 9, SIOP 93-01, SIOP 2001) for children with nephroblastoma (Wilms Tumour). The eighth study, SIOP UMBRELLA 2016 is ready to start.

The number of participating centres and countries has progressively increased and, in December 2007, a new collaborative structure was proposed to take forward the planning and implementation of new studies in children and adolescents affected by kidney tumours. This structure is named the SIOP-Renal Tumour Study Group (SIOP-RTSG).