Several different types of cancer can develop in the kidneys. Renal Cell Carcinoma, the most common form, accounts for over half of all cases. The malignant cancer cells develop in the lining of the kidney's tubules and grow into a tumor. In most cases, a single tumor develops, although more than one tumor can develop within one or both kidneys.

As with most types of cancer, early diagnosis of kidney cancer is important. The earlier the tumor is discovered, the better a person’s chances are for survival. Tumors found at an early stage regularly respond well to treatment. Survival rates in such cases are high. Tumors that have grown in size or spread through the bloodstream or lymphatic system to other parts of the body are harder to treat and cause an increased risk for mortality.