KIDNEY CANCER

Kidney cancer is a type of cancer that occurs in the cells of the kidney.

Cancer is caused by the rapid abnormal overgrowth of cells within the kidney. Our bodies are always making new cells: so we can grow, to replace worn-out cells, or heal damaged cells after injury. This process is controlled by certain genes and all cancers are caused by changes to these genes. Changes to our genes usually happen during our lifetime, although a small number of people inherit such a change from a parent.

As with all cancers, kidney cancers begin small and grow larger over time. Kidney cancers usually grow as a single mass but more than one tumour may occur in one or both kidneys. These lumps can be benign (not cancerous) or malignant (cancerous). Benign lumps do not spread to other parts of the body.

When it first develops, a malignant tumour is confined to its original site. If cancer is treated in its early stages, the potential for cure of the cancer can be very good. If these cells are not treated, they may spread into surrounding tissue and to other parts of the body. When these cells reach a new site they may continue to grow and form another tumour at that site.

• Primary cancer has not spread to the kidney from somewhere else. It is mostly a disease seen in adults over 40.
• Secondary cancers or "metastases" is cancer that has spread from somewhere else in the body. Secondary cancer in the kidney is more common than primary kidney cancer.

The average age of people found to have kidney cancer is 55 years. The disease is rare in children.