Understanding kidney cancer

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What is kidney cancer?  

The kidney is an integral part of the urinary system, producing urine by filtering excess water, salt and waste material from the blood. Kidneys are made up of a network of millions of small tubes called nephrons, which are each composed of a tubule and a corpuscle. Tubules are microscopic tubes that collect the waste materials and chemicals. Corpuscles have a clump of tiny blood vessels that filter the blood.1,2

Cells in the kidneys sometime change and no longer behave or grow normally. These changes may lead to non-cancerous (benign) conditions like cysts or non-cancerous tumours such as papillary renal adenoma. In some cases, however, these changes can cause kidney cancer.1

Areas of the kidney where cancer begins  

The most common type of kidney cancer is called renal cell carcinoma (RCC) and makes up approximately 90% of kidney cancer cases.2

There are

several subtypes of RCC

with the most common type being clear cell RCC where cells appear clear or very pale under the microscope.2,3 This type of cancer starts in the cells that line the tubules.1

It was estimated that in 2022,

8,100 Canadians

would be diagnosed with kidney and renal pelvis cancer.4

Risk factors include:5  

Age >50

 Overweight and obesity

Certain inherited genetic conditions

Family history of kidney cancer

Tall adult height

Smoking tobacco

High blood pressure

End-stage kidney disease and dialysis

Contact with trichloroethylene (TCE) (an industrial solvent)

Symptoms and diagnosis  

In earlier stages of kidney cancer, there may not be any signs or symptoms. However, as the tumour grows and the disease progresses, symptoms may be more apparent. Some of these symptoms can include:6

  • blood in the urine
  • pain in the back and side of the abdomen
  • a mass or lump that can be felt in the abdomen
  • swelling of the legs and ankles
  • high blood pressure
  • fatigue or night sweats
  • low red blood cell count (called anemia)
  • loss of appetite or weight loss

Your doctor may want to perform tests to help confirm or rule out a diagnosis.

Some of these tests include:7-9

Blood chemistry tests:A method used to measure substances such as electrolyte and other chemicals in the blood.

Ultrasound:A method using high-frequency sound waves to produce images, called sonograms, that are used to see inside of the abdomen and look for any changes in the kidneys.

Urinalysis:A test to measure substances like electrolytes, hormones and blood in the urine.

Computed tomography (CT) scan:A procedure that combines a series of x-ray images taken from different angles and uses computer processes to create 3D and cross-sectional images of the organs, tissues, bones and blood vessels inside the body.

Magnetic resonance imaging (MRI): A medical imaging exam that uses a magnetic field and computer-generated radio waves to create 3D and cross-sectional images of organs, tissues, bones and blood vessels.

Biopsy. A procedure to remove tissues or cells from the body so they can be tested in a lab.

If diagnosed, your doctor will evaluate your condition based on the stage and type of kidney cancer.

References: 1. Canadian Cancer Society. What is kidney cancer? Available at: https://cancer.ca/en/cancer-information/cancer-types/kidney/what-is-kidney-cancer Last accessed February 27, 2023. 2. American Cancer Society. What is Kidney Cancer? Available at: https://www.cancer.org/cancer/kidney-cancer/about/what-is-kidney-cancer.html Last accessed February 27, 2023. 3. Cancer.net. Kidney Cancer: Introduction. Available at: https://www.cancer.net/cancer-types/kidney-cancer/introduction Last accessed February 27, 2023. 4. Canadian Cancer Society. Kidney cancer statistics. Available at: https://cancer.ca/en/cancer-information/cancer-types/kidney/statistics Last accessed February 27, 2023. 5. Canadian Cancer Society. Risk factors for kidney cancer. Available at: https://cancer.ca/en/cancer-information/cancer-types/kidney/risks Last accessed February 27, 2023. 6. Canadian Cancer Society. Symptoms of kidney cancer. Available at: https://cancer.ca/en/cancer-information/cancer-types/kidney/signs-and-symptoms Last accessed February 27, 2023. 7. Canadian Cancer Society. Diagnosis of kidney cancer. Available at: https://cancer.ca/en/cancer-information/cancer-types/kidney/diagnosis Last accessed February 27, 2023. 8. Mayo Clinic. CT Scan. Available at: https://www.mayoclinic.org/tests-procedures/ct-scan/about/pac-20393675 Last accessed March 7, 2023. 9. Mayo Clinic. MRI. Available at: https://www.mayoclinic.org/tests-procedures/mri/about/pac-20384768 Last accessed March 7, 2023.