Diagnosing Kidney Cancer

Because the kidneys are deep in the body, it is not easy to feel a lump in the kidney or see from the outside what is happening beneath the surface.

Often kidney cancer is found by accident — “an incidental finding” — when the doctor does a scan for another reason and notices something on the kidney.  This is actually a good thing, as it may identify a problem early, before you even notice it. Once kidney cancer is suspected for any reason, additional tests will be needed to determine just what is happening.

The most common tests that may be ordered include:

  • Ultrasound: A type of scan where a probe is slid over the skin and where the x-ray team looks for irregularities in the kidney and other organs.
  • MRI/ CT Scans: Computed tomography (CT) scan or magnetic resonance imaging (MRI) scans can be used to get detailed pictures of organs in the body. This can help characterise a lump in the kidney if one is found.
  • Chest x-ray: An x-ray of organs and bones within the chest.
  • Urine test (urinalysis): The most common symptom and sign of a kidney tumour is blood in the urine. This test can also detect other irregularities in the urine such as protein.
  • Blood tests: Chemical tests of the blood can detect findings associated with kidney cancer.
  • Bone scan: A small amount of radioactive material is injected into a vein and travels through the bloodstream to the bones so the scanner can detect if cancer has spread to the bones.

The majority of kidney cancers are initially discovered by scans (ultrasound, CT scan, or MRI), showing something like a “lump” on the kidney. This does not prove it is kidney cancer however, and it must be examined under the microscope to be sure. Sometimes your doctor may be so suspicious they recommend immediate surgery; other times your doctor might order a biopsy. During a biopsy, a thin needle is used to remove some cells from the tumour. A doctor will then look at the cells to see if they are cancerous or not. Up to 20% of small kidney masses (or lumps) are non-cancerous.