Kidney cancer starts in the kidneys. Your kidneys are two bean-shaped organs, each about the size of your fist. They’re located right behind your abdominal organs, with one kidney on every side of your spine.
In adults, renal cell carcinoma is the most common type of kidney cancer — about 90% of cancerous tumors. Other less common types of kidney cancer can happen. Young children are more likely to develop a kind of kidney cancer is referred to as Wilms’ tumor.
The incidence of kidney cancer seems to be increasing. One reason for this may be the fact that imaging methods such as computerized tomography (CT) scans are being used more often. These tests may lead to the accidental discovery of more kidney cancers. In some cases, kidney cancer is found at an early stage, when the tumors are small and confined to the kidney, making them easier to treat.