Wilms tumour is the most common type of kidney cancer in children. However, a large international study, involving 16,000 children with malignant kidney tumours collected from more than 308 cancer registries on 5 continents has shown that the proportion of renal cell carcinomas (RCC) increased with age, and the incidence of RCC increased over time. The researchers think this might be related to environmental factors.
Wilms tumour was found to be the most common type of renal tumour in children aged 0 to 14 years, both in all the different world regions and in different ethnic groups in the US. Wilms tumours also constituted more than 90% of all renal tumours in each age group from 1 to 7 years, but the proportion of RCC also rose with age.