Kidney Cancer/Adrenal Cancer
Your kidneys are two bean-shaped organs located on either side of your spine, just below your rib cage.
Your kidneys remove waste products and extra fluid from your body. They also regulate your body’s salt, potassium, and acid content to help balance your body chemistry. They also make hormones to stimulate red blood cell production, help regulate blood pressure, and control calcium metabolism.
Each kidney is made of over a million blood-filtering units called nephrons. Nephrons work to clear your blood of impurities to make urine. Nephrons connect to collecting ducts. These ducts drain urine into the renal pelvis. This funnel-shaped area connects to the ureters—tubes that connect each kidney to your bladder.
When cancer starts in the part of the kidney that filters blood, it’s called a renal cortical tumor. When cancer starts in the renal pelvis, it’s called urothelial cancer. For information about urothelial cancer, please see the section on bladder cancer.
About 51,200 men and women are diagnosed with kidney cancer each year in the US. Men are affected almost twice as often as women. Children rarely develop the disease.
The most common type of adult kidney cancer is renal cell carcinoma. It accounts for about 85% of cases. Renal cell carcinomas are classified into four types, which can help predict the tumor's behavior:
- Conventional clear cell carcinoma. About 75–80% of renal cell carcinomas. This type is associated with loss of part of chromosome 3. Certain genes, especially the von Hippel-Lindau gene, are associated with clear cell carcinoma.
- Papillary cancer. About 10–15% of renal cell carcinomas. These tumors happen in multiple parts of the kidney. They may also be found in both kidneys at diagnosis.
- Chromophobe carcinomas. About 5–10% of renal cell carcinomas. This type generally has a good outcome. People usually have a lower risk of progression and death when compared to clear cell carcinoma.
- Oncocytomas. About 3–7% of renal cell carcinomas. This type rarely becomes invasive or spreads.
Some people have a very rare form of kidney cancer called collecting duct tumors. They tend to happen in younger patients. They are unfortunately aggressive and difficult to treat.
Your doctor may conduct the following tests for kidney cancer:
A pathologist examines a sample of your urine under a microscope to check for any cancerous or precancerous cells. They may also do a urine culture to rule out an infection, which can cause similar symptoms.
CT scans are the best test to find out if you have a kidney tumor. A CT scanner rotates around your body and takes multiple pictures that are combined to create a 3D image of your body—your skeleton and tissues, such as your kidneys.
A radiologist uses sound waves to distinguish between tumors and fluid-filled cysts, which are not cancerous.
A Magnetic Resonance Imaging (MRI) test uses powerful magnetic fields to take pictures that detect tumors in the kidneys or the kidney’s blood vessels.
Doctors may recommend a biopsy of your kidney tumor. This can help determine if the tumor is cancerous or not. If it is cancerous, the biopsy can often determine the type of cancer and how aggressive it is. This procedure is performed by a doctor specializing in interventional radiology as an outpatient procedure, meaning it does not require an overnight hospital stay. The interventional radiology doctor will place some numbing medicine on your skin and using a needle, will take a tissue sample of the tumor. The doctor will use either an ultrasound or CT scan to guide them to the precise spot. Then, a pathologist will look at the tissue to determine if there are any abnormal cells.
Most people in the US with kidney cancer are diagnosed with the disease before they have symptoms, thanks to routine imaging tests.
The most common symptom of kidney cancer is blood in your urine. It’s important to talk to your doctor if you have that or other symptoms, including:
- Lower back pain that doesn’t go away
- A lump in your abdomen
- Fatigue or unexplained tiredness
- Loss of appetite
- Rapid weight loss for no apparent reason
- Fever unrelated to an infection, such as the flu
- Swollen ankles and legs
- High blood pressure
- Anemia, or low red blood cell counts
Kidney Cancer Risks
Many kidney cancer risks are out of your control. Here are known risk factors for developing kidney cancer:
- Smoking. Cigarette smoking can double your risk of kidney cancer. This habit contributes to about 33% of kidney cancer. Smokers often have more advanced cancer when it’s found.
- High blood pressure. Having high blood pressure can increase your risk for kidney cancer.
- Obesity, diet. Some studies show that being overweight and eating a high-fat diet can raise your risk of kidney cancer.
- Workplace exposure. Exposure to chemicals at work can increase your risk of kidney cancer. Petroleum products, heavy metals, cadmium (in batteries, paints, or welding materials), or asbestos are some examples.
- Genetic mutation. Changes in certain genes, either inherited or affected by your environment, can increase your risk of kidney cancer. There are several inherited genetic mutations that can cause kidney cancer, including von Hippel-Lindau syndrome, hereditary leiomyomatosis, renal cell carcinoma, hereditary papillary renal cell carcinoma, and several others.
- Other disorders. Polycystic disorders that affect the kidneys, liver, or pancreas can increase your risk of kidney cancer, as can long-term dialysis.