Wilms tumour treatment in children — kidney cancer your child can face with the right team

Wilms tumour, also called nephroblastoma, is a cancer of the kidney that starts in cells that were meant to form normal kidney tissue during a child’s development. It is the most common kidney cancer in children and occurs almost exclusively in young children, typically between the ages of three and five years. The tumour forms because a small group of primitive kidney cells called metanephric blastema fail to mature normally after birth. Instead of developing into functional kidney tissue, they continue dividing and form a tumour. Most cases are sporadic — arising by chance without any family history or known risk factor. A small number of cases are associated with certain developmental conditions that a doctor may have already identified. The condition is not caused by anything a parent did before or during pregnancy.

The most common sign of Wilms tumour is a smooth, firm lump or swelling in a child’s abdomen — often first noticed by a parent during bathing or dressing, or by a doctor during a routine check. The lump is usually on one side of the abdomen and typically does not cause pain. Other signs that sometimes occur include blood in the urine (which may make the urine look pink or red), high blood pressure, a persistent low fever, loss of appetite, or the child appearing generally unwell or more tired than usual. It is important to note that a noticeable abdominal lump in a young child always warrants prompt medical assessment — even if the child seems otherwise well. Most abdominal lumps turn out to have a non-cancer cause, but a kidney tumour must be ruled out quickly.

When a doctor suspects a kidney tumour, the first investigation is usually an abdominal ultrasound scan, which can show the size and position of the tumour. This is followed by a CT scan or MRI of the abdomen and chest to get a detailed picture of the tumour, to check whether it involves both kidneys, and to look for spread to the lymph nodes, liver, or lungs. Blood and urine tests are done to assess kidney function and overall health. A biopsy — taking a small sample of the tumour to examine under a microscope — is the definitive step that confirms the diagnosis and identifies the tumour’s histology (how the cells look). Wilms tumour histology is classified as either favourable or anaplastic (unfavourable), and this classification has an important influence on how treatment is planned. No biopsy and no treatment plan should begin without a specialist paediatric oncology review.

Staging describes how far the cancer has spread from where it started. Wilms tumour is staged from I to V. Stage I means the tumour is confined to one kidney and has been completely removed by surgery. Stage II means the tumour has grown slightly beyond the kidney (into surrounding fat or blood vessels) but has still been completely removed. Stage III means there is residual tumour in the abdomen after surgery, or the tumour was ruptured before or during surgery, or lymph nodes in the abdomen contain cancer cells. Stage IV means the cancer has spread through the bloodstream to distant organs, most commonly the lungs. Stage V — the most complex situation — means both kidneys are involved. Staging and histology together determine which treatment programme is recommended and how intensive it will be.

Treatment involves a combination of surgery, chemotherapy, and in some cases radiation therapy, delivered in a carefully sequenced programme. Surgery to remove the affected kidney (nephrectomy) is a central part of treatment; the approach and timing depend on the stage and whether both kidneys are involved. Chemotherapy is used both before surgery (to shrink the tumour) and after surgery (to eliminate any remaining cancer cells). Radiation therapy to the abdomen or chest is added in certain higher-stage or anaplastic cases. Because both kidneys are involved in Stage V cases, the aim is to preserve as much functional kidney tissue as possible while still removing all tumour, which requires careful surgical planning. Every child’s plan is designed by a multidisciplinary team and reviewed at a tumour board before any treatment begins.

Many children treated for Wilms tumour go on to live full, healthy lives. With one functioning kidney, children can generally maintain normal kidney function, and they grow and develop in the same way as their peers. However, long-term follow-up by a specialist team is important: the remaining kidney must be monitored regularly to ensure it stays healthy, blood pressure should be checked, and the child’s overall growth and development needs ongoing attention. Children who received radiation therapy may also need specific long-term monitoring depending on which area was treated. The goal of care at CION is not just to treat the cancer — we walk this journey with your family and plan the follow-up programme so that nothing falls through the cracks after active treatment ends.