Kidney cancer often goes undiscovered until the later stages for a few reasons:
- These cancers can become quite large before they cause pain or other symptoms.
- Kidneys are deep inside the body, so small kidney tumors cannot be seen or felt during a physical exam.
- There are no recommended screening tests for people who are not at increased risk for the disease.
- The symptoms of kidney cancer are often caused by other, benign, diseases.
Symptoms of kidney cancer may include blood in the urine, low back pain on one side, a mass or lump on the side or lower back, tiredness (fatigue), loss of appetite, weight loss, recurrent fevers not associated with colds or flu, and swelling of the ankles and legs.
You should tell your doctor if you have any of these symptoms.
Doctors may use several tests to diagnose kidney cancer, including a biopsy, genetic tests, and imaging scans. Blood tests may be useful for providing prognostic (potential outcome) information.
A biopsy is a procedure that involves removing a small amount of tissue for examination under a microscope by a pathologist. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The pathologist identifies the type of cell involved in the kidney cancer, which is important in planning treatment.
Genetic tests look for gene mutations in your DNA. If you have family members (direct blood relatives) who were diagnosed with kidney cancer, especially at a younger age, or with a genetic condition that is a risk factor for kidney cancer (see risk factors), your doctor may recommend that you consider genetic testing.
OncoScan CGAT, a new chromosome genomic array test at Seattle Cancer Care Alliance, can help identify genetic changes useful in diagnosing kidney cancer, understanding the risk of recurrence and outlook for survival, and guiding therapy decisions. This test looks at the entire genome. It can help determine the subtype of your kidney cancer, like clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, and others.
Imaging tests look at the inside of the body. They may be used to help find out whether a suspicious area is cancerous, to determine if the cancer has spread (metastasized), and to help determine if treatments have been effective. These are the most common imaging tests used for kidney cancer:
- Ultrasound (or ultrasonography, sonogram) uses sound waves to produce images of internal organs. This type of imaging can help determine if a kidney mass is solid or filled with fluid.
- Intravenous pyelogram (IVP) uses a dye that is injected into the patient’s bloodstream to highlight the kidney, urethra, and bladder when an X-ray is taken. The picture produced can show changes in these organs and in the nearby lymph nodes.
- Computed tomography (CT) scan creates a three-dimensional picture of the inside of the body with an X-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
- Magnetic resonance imaging (MRI) uses magnetic fields to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.
Blood tests can be used to check the number of blood cells, electrolytes, and enzyme levels. These tests may identify abnormalities caused by kidney cancer.
Risk factors for kidney cancer include:
- Age. The risk of kidney cancer increases as you age. Kidney cancer is uncommon in people younger than 45. It occurs most often in people 55 or older. The average age at diagnosis is 64.
- Sex. RCC is about twice as common in men as in women.
- Smoking. Smokers are twice as likely to get kidney cancer as nonsmokers.
- Obesity and diet. Being overweight and having a high-fat diet increase the risk of getting kidney cancer.
- Exposure to certain environmental substances. Asbestos, cadmium (a trace metal), and organic solvents are among the substances that raise kidney cancer risk.
- Genetic and hereditary factors. Having kidney disease or a family history of kidney cancer puts you at greater risk.
- High blood pressure. Risk for kidney cancer is elevated in people with high blood pressure.
- Race. For reasons that are unclear, African-Americans have a slightly high rate of RCC.
Five inherited diseases result from a faulty gene that makes a person more susceptible to kidney cancer:
- Von Hippel-Lindau syndrome
- Birt-Hogg-Dube syndrome
- Hereditary papillary RCC
- Hereditary leiomyomatosis
- RCC syndromes
People with Lynch syndrome may also be at greater risk for kidney cancers.