Kidney cancer is cancer that begins in the kidneys. Your kidneys are two bean-shaped organs, each about the size of your fist. They're located behind your abdominal organs, with one kidney on each side of your spine. Kidneys excrete excess water and control fluid and electrolyte balance.
In adults, renal cell carcinoma is the most common type of kidney cancer. Other less common types of kidney cancer can occur. Young children are more likely to develop a kind of kidney cancer called Wilms' tumor.
The incidence of kidney cancer seems to be increasing. One reason for this may be the fact that imaging techniques such as computerized tomography (CT) scans are being used more often. These tests may lead to the accidental discovery of more kidney cancers. Kidney cancer is often discovered at an early stage, when the cancer is small and confined to the kidney.
Kidney cancer usually doesn't have signs or symptoms in its early stages. In time, signs and symptoms may develop, including:
- Blood in your urine, which may appear pink, red or cola colored
- Pain in your back or side that doesn't go away
- Loss of appetite
- Unexplained weight loss
It's not clear what causes most kidney cancers.
Doctors know that kidney cancer begins when some kidney cells develop changes (mutations) in their DNA. A cell's DNA contains the instructions that tell a cell what to do. The changes tell the cells to grow and divide rapidly. The accumulating abnormal cells form a tumor that can extend beyond the kidney. Some cells can break off and spread (metastasize) to distant parts of the body.
Factors that can increase the risk of kidney cancer include:
- Older age. Your risk of kidney cancer increases as you age.
- Smoking. Smokers have a greater risk of kidney cancer than nonsmokers do. The risk decreases after you quit.
- Obesity. People who are obese have a higher risk of kidney cancer than people who are considered to have a healthy weight.
- High blood pressure (hypertension). High blood pressure increases your risk of kidney cancer.
- Treatment for kidney failure. People who receive long-term dialysis to treat chronic kidney failure have a greater risk of developing kidney cancer.
- Certain inherited syndromes. People who are born with certain inherited syndromes may have an increased risk of kidney cancer, such as those who have von Hippel-Lindau disease, Birt-Hogg-Dube syndrome, tuberous sclerosis complex, hereditary papillary renal cell carcinoma or familial renal cancer.
- Family history of kidney cancer. The risk of kidney cancer is higher if close family members have had the disease.
Taking steps to improve your health may help reduce your risk of kidney cancer. To reduce your risk, try to:
- Quit smoking. If you smoke, quit. Many options for quitting exist, including support programs, medications and nicotine replacement products. Tell your doctor you want to quit, and discuss your options together.
- Maintain a healthy weight. Work to maintain a healthy weight. If you're overweight or obese, reduce the number of calories you consume each day and try to be physically active most days of the week. Ask your doctor about other healthy strategies to help you lose weight.
- Control high blood pressure. Ask your doctor to check your blood pressure at your next appointment. If your blood pressure is high, you can discuss options for lowering your numbers. Lifestyle measures such as exercise, weight loss and diet changes can help. Some people may need to add medications to lower their blood pressure. Discuss your options with your doctor.
Tests and procedures used to diagnose kidney cancer include:
- Blood and urine tests. Tests of your blood and your urine may give your doctor clues about what's causing your signs and symptoms.
- Imaging tests. Imaging tests allow your doctor to visualize a kidney tumor or abnormality. Imaging tests might include ultrasound, X-ray, CT or MRI.
- Removing a sample of kidney tissue (biopsy). In some situations, your doctor may recommend a procedure to remove a small sample of cells (biopsy) from a suspicious area of your kidney.
Kidney cancer staging
Once your doctor identifies a kidney lesion that might be kidney cancer, the next step is to determine the extent (stage) of the cancer. Staging tests for kidney cancer may include additional CT scans or other imaging tests your doctor feels are appropriate.
The stages of kidney cancer are indicated by Roman numerals that range from I to IV, with the lowest stages indicating cancer that is confined to the kidney. By stage IV, the cancer is considered advanced and may have spread to the lymph nodes or to other areas of the body.
Kidney cancer treatment usually begins with surgery to remove the cancer. For cancers confined to the kidney, this may be the only treatment needed. If the cancer has spread beyond the kidney, additional treatments may be recommended.
For most kidney cancers, surgery is the initial treatment. The goal of surgery is to remove the cancer while preserving normal kidney function, when possible. Operations used to treat kidney cancer include:
- Removing the affected kidney (nephrectomy). A complete (radical) nephrectomy involves removing the entire kidney, a border of healthy tissue and occasionally additional nearby tissues such as the lymph nodes, adrenal gland or other structures.The surgeon may perform a nephrectomy through a single incision in the abdomen or side (open nephrectomy) or through a series of small incisions in the abdomen (laparoscopic or robotic-assisted laparoscopic nephrectomy).
- Removing the tumor from the kidney (partial nephrectomy). Also called kidney-sparing or nephron-sparing surgery, the surgeon removes the cancer and a small margin of healthy tissue that surrounds it rather than the entire kidney. It can be done as an open procedure, or laparoscopically or with robotic assistance.Kidney-sparing surgery is a common treatment for small kidney cancers and it may be an option if you have only one kidney. When possible, kidney-sparing surgery is generally preferred over a complete nephrectomy to preserve kidney function and reduce the risk of later complications, such as kidney disease and the need for dialysis.
The type of surgery your doctor recommends will be based on your cancer and its stage, as well as your overall health.
Small kidney cancers are sometimes destroyed using nonsurgical treatments, such as heat and cold. These procedures may be an option in certain situations, such as in people with other health problems that make surgery risky.
Options may include:
- Treatment to freeze cancer cells (cryoablation). During cryoablation, a special hollow needle is inserted through your skin and into the kidney tumor using ultrasound or other image guidance. Cold gas in the needle is used to freeze the cancer cells.
- Treatment to heat cancer cells (radiofrequency ablation). During radiofrequency ablation, a special probe is inserted through your skin and into the kidney tumor using ultrasound or other imaging to guide placement of the probe. An electrical current is run through the needle and into the cancer cells, causing the cells to heat up or burn.
Treatments for advanced and recurrent kidney cancer
Kidney cancer that comes back after treatment and kidney cancer that spreads to other parts of the body may not be curable. Treatments may help control the cancer and keep you comfortable. In these situations, treatments may include:
- Surgery to remove as much of the kidney cancer as possible. If the cancer can't be removed completely during an operation, surgeons may work to remove as much of the cancer as possible.
- Targeted therapy. Targeted drug treatments focus on specific abnormalities present within cancer cells. By blocking these abnormalities, targeted drug treatments can cause cancer cells to die.
- Immunotherapy. Immunotherapy uses your immune system to fight cancer. Your body's disease-fighting immune system may not attack your cancer because the cancer cells produce proteins that help them hide from the immune system cells. Immunotherapy works by interfering with that process.
- Radiation therapy. Radiation therapy uses high-powered energy beams from sources such as X-rays and protons to kill cancer cells. Radiation therapy is sometimes used to control or reduce symptoms of kidney cancer that has spread to other areas of the body, such as the bones and brain.