Your kidneys filter and remove waste and excess fluids from your blood, which leave your body when you urinate. Kidney cancer occurs when diseased cells form a tumor in one or both of your kidneys. These cancerous cells multiply and grow out of control.

Kidney cancer is one of the top 10 most common cancers affecting adults. You may also hear the term renal cancer, since renal is the medical term for your kidneys.

Around 9 in 10 kidney cancers are a type called renal cell carcinoma (RCC). This cancer forms in tiny kidney tubes called tubules that filter your blood. The most common RCC subtype — clear cell RCC — is made up of cells that look very pale or clear under a microscope.

Other types of kidney cancer include:

• Chromophobe RCC: Cancer cells look like clear cell RCC, but they’re larger.
• Papillary RCC: Tiny finger-like projections called papillae form in the tumor.
• Renal sarcoma: These rare tumors form in the blood vessels or connective tissue of the kidney.
• Transitional cell (urothelial) carcinoma: Cancer forms in urothelial cells that line the center of the kidney (renal pelvis) where urine collects.
• Wilms tumor (nephroblastoma): This kidney cancer is mostly a pediatric kidney cancer. It’s extremely rare in adults.

Kidney cancer doesn’t always cause symptoms, especially when the cancer tumor is small.

Common Symptoms

When they are present, signs and symptoms of kidney cancer include:

• Blood in your urine
• Extreme, unexplained fatigue
• Loss of appetite and unplanned weight loss
• Lower back pain or lump
• Persistent fever
• Swollen ankles, feet and legs

Medical experts don’t always know why kidney cells become cancerous. Sometimes it’s because a change in your genes (mutation) makes you more prone to kidney cancer.

About 8% of kidney cancers are inherited. Cancer-causing gene changes can also occur naturally or from environmental factors, such as smoking.

There are some risk factors that make you more at risk for kidney cancer, including:

Physicians rely on physical exams, your medical history and a variety of tests to diagnose kidney cancer.

Diagnostic tests for kidney cancer include:

• Blood tests: A blood test can show if there’s a problem with your kidneys. It can also detect anemia (low red blood cell levels) caused by kidney cancer.
• Urine tests: A urinalysis detects blood and protein in urine, which may indicate kidney cancer.
• Imaging tests: A CT scan, MRI or ultrasound can detect kidney tumors.
• Kidney biopsy: A physician removes a small sample of tissue from your tumor and checks it for cancer cells. Physicians tend to use imaging scans more than biopsies to diagnose kidney cancer.

Cancer experts at our Department of Pathology and Laboratory Medicine and Department of Radiology examine the test results to determine whether you may have kidney cancer and the subtype.

Treatments for kidney cancer vary depending on the cancer stage, type and other factors, such as your age and overall health.

Kidney cancer surgery (nephrectomy) is an important treatment. If the cancer hasn’t spread outside of the kidney (metastatic kidney cancer), surgery (removing part or the whole kidney) often cures the disease.

Physicians sometimes use nonsurgical treatments for small kidney tumors that only affect the kidney. You may also get nonsurgical treatment if you don’t want surgery or can’t get it due to health reasons.

Drug therapies treat metastatic (stage 4) kidney cancer that spreads outside the kidney. Medications can also help if you don’t want, or can’t get, surgery. Some people take medications after surgery to lower the risk of kidney cancer coming back. This is known as adjuvant therapy.

Kidney cancer specialists at our cancer center work together to customize a treatment plan for your unique condition. We provide the latest cancer treatments and services, including:

Because kidney cancer usually develops for no known reason, there often isn’t a way to prevent it. Still, you can take these steps to lower your risk:

• Avoid exposure to harmful chemicals.
• Maintain a healthy weight or lose excess weight if necessary.
• Manage high blood pressure.
• Seek help to quit smoking through our Stop Tobacco Program (SToP).