Kidney cancer is cancer that begins in the kidneys, which are two bean-shaped organs located behind the abdominal organs, one on each side of the spine. Renal cell carcinoma is the most common type of kidney cancer in adults. Staging of renal cell cancer involves determining how far the cancer has spread from the kidneys to other parts of the body. Diagnostic evaluation of kidney cancer involves examining the kidneys and surrounding areas to determine if the cancer has spread.