Diagnosing and treating any cancer early gives a person a better chance of recovery. If tumors have a chance to grow large or spread through the body, the cancer is then harder to treat and poses a greater risk.

Since early kidney cancers usually cause no symptoms, kidney cancer is often detected when a person is having tests for some other purpose. Whether suspected from an incidental test finding or from patient-reported symptoms, the condition is first addressed by a doctor through a medical history and a physical exam (including feeling the abdomen for lumps or irregular masses). This may be followed by lab tests on blood and urine.

The doctor may also want to order certain types of imaging studies, which provide different kinds of pictures of the kidneys, its surrounding area and nearby organs:

• A CT scan will give detailed, cross-sectional pictures of the inside of the body. A solid mass in the kidney on CT images means a high likelihood of kidney cancer. The CT can also sometime show if the cancer has spread to other areas such as the lymph nodes in the abdomen, liver or chest.
• An MRI can also give information as to the nature of the mass in the kidney. It can show the tissues and blood vessels in and around the kidney.
• An ultrasound can reveal masses in the kidney and surrounding area.
• For an intravenous pyelogram (IVP), the patient receives an injection of a contrast dye into the bloodstream. The dye collects in and passes through the urinary tract. X-rays of this system then show tumors or damage from them as contrasting image areas. An IVP provides information about the structure and function of the kidneys, ureters and bladder.
• If you have blood in the urine, a doctor may recommend a cystoscopy. In this test, the urologist inserts a long, thin tube (an endoscope) up through the urethra to visually examine the urinary tract and determine where bleeding is occurring. This test can help find cancer in the urethra, bladder or kidney. Sometimes, a needle biopsy, inserting a long, thin needle through the skin to take a sample of any mass that has been detected is necessary. A pathologist can examine the sampled tissue for cancer cells. Needle biopsy of masses in the kidney are not routine to make the diagnosis before surgery since the CT and other X-rays are very accurate at determining malignant tumors of the kidney.
• Chest X-rays can help determine if the cancer has spread to the lungs, the bones of the chest or other areas. A bone scan can also reveal spread of the cancer to the bones.

As kidney cancer advances, it may spread to the nearby lymph system or organs, or metastasize to other parts of the body. In order to know how to treat the disease, the doctor needs to know the stage of the cancer, and all of the above procedures add information to this effort. Staging is a careful attempt to determine how far a cancer has progressed, the type or grade of the cancer, and the extent and nature of its spread, if any. Cells from renal tumors, for example, fall into a number of types that can tell the cancer specialist how aggressive the cancer is likely to be. Examining lymph nodes removed during surgery may also reveal whether the cancer has spread and what type of cells are in it.