Wilms' tumour arises from the embryonal tissues in the kidney. It affects children of all ages but is mostly found in one- to three-year-olds. The tumour usually develops in one kidney but some children may have both kidneys affected. A few children with Wilms' tumour may have other abnormalities at birth or in early childhood, such as hemihypertrophy (when one arm or leg, or one side of the body, is larger than the other) and aniridia (when the iris, the coloured portion of the eye, is absent).
Most children with Wilms' tumour show no symptom initially but a swelling may be accidentally noticed in the child's abdomen when the parent plays with, baths or dresses him. When the tumour grows and begins to spread, the child may suffer from pain in the abdomen or may pass blood in his urine. By then, the child has begun to lose weight and is pale.
An ultrasound and/or computerised tomography (CT) scan of the kidneys will be carried out to find out precisely where the tumour is. Blood tests are usually taken to check the child's liver and kidney condition. Sometimes other tests are necessary, including intravenous urography, chest radiography and a CT scan of the chest to see whether the cancer has spread outside the kidney.
The mainstay of treatment is by surgical removal of the affected kidney. Chemotherapy may be given to shrink the tumour first so that the operation is easier. The surgeon will also examine the area around the tumour as well as the child's liver and kidneys to define how far the cancer has spread. When the cancer has already spread outside the kidney, chemotherapy and radiotherapy will be also given.
Chemotherapy will be given for six months to a year and the types of drugs and the length of treatment will depend on the stage of the tumour.
Most children with Wilms' tumour are cured, and even if the cancer has spread beyond the kidney, more than 50 per cent of the cases survive. Although one of the kidneys is removed, the child can still live a normal life.