Wilms’ tumour is a type of embryonal tumour, developing from the immature cells from which the kidneys develop. It is thought these cells do not mature normally, instead they remain present in a child’s kidney after birth, then they start to grow out of control, forming a jumbled mass of small immature cells.
Wilms’ tumour usually only affects one kidney (unilateral) but, in rare cases, can affect both (bilateral).
Wilms’ tumour is one of the most common types of childhood cancer, affecting around 80 children a year in the UK.
As with other embryonal tumours, Wilms’ tumour predominantly affects children under the age of 5; the peak incidence is between 1-3 years of age.
Unilateral tumours occur equally often in boys and girls, but girls are twice as likely to be diagnosed with bilateral tumours.
Although the causes of Wilms’ tumour are unknown, some people who develop it have abnormal genes or congenital malformations. Up to one in six children diagnosed with Wilms’ tumour also have a malformation syndrome, such as WAGR syndrome, Denys-Drash syndrome or Beckwith-Weidemann syndrome – the highest proportion recorded for any childhood malignancy.
In one in 100 cases, another family member will also have Wilms’ tumour.
Most children with Wilms’ tumour can be cured, with 90% of patients surviving to five years.
Survival is better for children with unilateral Wilms’ tumour than for those with bilateral disease.
Children with other types of renal tumour have a worse prognosis. Rhabdoid renal tumour, whilst rare, unfortunately has few survivors.
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