Kidney cancer is any of several types of cancer can start in the kidney. The most common type of kidney cancer in adults is renal cell cancer, which is also called renal adenocarcinoma or hypernephroma. Another type of cancer, transitional cell carcinoma, affects the renal pelvis. It is similar to bladder cancer and is often treated like bladder cancer. Wilms' tumor is the most common type of childhood kidney cancer. It is different from adult kidney cancer and requires different treatment.

 

What follows applies specifically to renal cell cancer.

 

Risk factors

Kidney cancer develops most often in people over 40, but no one knows the exact causes of this disease. Doctors can seldom explain why one person develops kidney cancer and another does not. However, it is clear that kidney cancer is not contagious. No one can "catch" the disease from another person.

 

Research has shown that people with certain risk factors are more likely than others to develop kidney cancer. A risk factor is anything that increases a person's chance of developing a disease.

 

Studies have found the following risk factors for kidney cancer:

 

Smoking: Cigarette smoking is a major risk factor. Cigarette smokers are twice as likely as nonsmokers to develop kidney cancer. Cigar smoking also may increase the risk of this disease.

Obesity: People who are obese have an increased risk of kidney cancer.

High blood pressure: High blood pressure increases the risk of kidney cancer.

Long-term dialysis: Renal dialysis is a treatment for people whose kidneys do not work well. It removes wastes from the blood. Being on dialysis for many years is a risk factor for kidney cancer.

Von Hippel-Lindau (VHL) syndrome: VHL is a rare disease that runs in some families. It is caused by changes in the VHL gene. An abnormal VHL gene increases the risk of kidney cancer. It also can cause cysts or tumors in the eyes, brain, and other parts of the body. Family members of those with this syndrome can have a test to check for the abnormal VHL gene. For people with the abnormal VHL gene, doctors may suggest ways to improve the detection of kidney cancer and other diseases before symptoms develop.

Occupation: Some people have a higher risk of getting kidney cancer because they come in contact with certain chemicals or substances in their workplace. Coke oven workers in the iron and steel industry are at risk. Workers exposed to asbestos or cadmium also may be at risk.

Gender: Males are more likely than females to be diagnosed with kidney cancer. Each year in the United States, about 20,000 men and 12,000 women learn they have kidney cancer.

 

Most people who have these risk factors do not get kidney cancer. On the other hand, most people who do get the disease have no known risk factors.

 

Symptoms

Common symptoms of kidney cancer include:

 

Blood in the urine (making the urine slightly rusty to deep red)

Pain in the side that does not go away

A lump or mass in the side or the abdomen

Weight loss

Fever

Feeling very tired or having a general feeling of poor health

 

Most often, these symptoms do not mean cancer. An infection, a cyst, or another problem also can cause the same symptoms. A person with any of these symptoms should see a doctor so that any problem can be diagnosed and treated as early as possible.

 

Diagnosis

If a patient has symptoms that suggest kidney cancer, the doctor may perform one or more of the following procedures:

 

Physical exam: The doctor checks general signs of health and tests for fever and high blood pressure. The doctor also feels the abdomen and side for tumors.

Urine tests: Urine is checked for blood and other signs of disease.

Blood tests: The lab checks the blood to see how well the kidneys are working. The lab may check the level of several substances, such as creatinine. A high level of creatinine may mean the kidneys are not doing their job.

Intravenous pyelogram (IVP): The doctor injects dye into a vein in the arm. The dye travels through the body and collects in the kidneys. The dye makes them show up on X-rays. A series of X-rays then tracks the dye as it moves through the kidneys to the ureters and bladder. The X-rays can show a kidney tumor or other problems.

CT scan (CAT scan): An X-ray machine linked to a computer takes a series of detailed pictures of the kidneys. The patient may receive an injection of dye so the kidneys show up clearly in the pictures. A CT scan can show a kidney tumor.

Ultrasound test: The ultrasound device uses sound waves that people cannot hear. The waves bounce off the kidneys, and a computer uses the echoes to create a picture called a sonogram. A solid tumor or cyst shows up on a sonogram.

Biopsy: In some cases, the doctor may do a biopsy. A biopsy is the removal of tissue to look for cancer cells. The doctor inserts a thin needle through the skin into the kidney to remove a small amount of tissue. The doctor may use ultrasound or X-rays to guide the needle. A pathologist uses a microscope to look for cancer cells in the tissue.

Surgery: In most cases, based on the results of the CT scan, ultrasound, and X-rays, the doctor has enough information to recommend surgery to remove part or all of the kidney. A pathologist makes the final diagnosis by examining the tissue under a microscope.

 

Staging

To plan the best treatment, the doctor needs to know the stage (extent) of the disease. The stage is based on the size of the tumor, whether the cancer has spread and, if so, to what parts of the body (see illustration above).

 

Staging may involve imaging tests such as an ultrasound or a CT scan. The doctor also may use an MRI. For this test, a powerful magnet linked to a computer makes detailed pictures of organs and blood vessels.

 

Doctors describe kidney cancer by the following stages:

 

Stage I is an early stage of kidney cancer. The tumor measures up to 2¾ in (7 cm). It is no bigger than a tennis ball. The cancer cells are found only in the kidney.

Stage II is also an early stage of kidney cancer, but the tumor measures more than 2¾ in. The cancer cells are found only in the kidney.

Stage III is one of the following:

      - The tumor does not extend beyond the kidney, but cancer cells have spread through the lymphatic system to one nearby lymph node; or

      - The tumor has invaded the adrenal gland or the layers of fat and fibrous tissue that surround the kidney, but cancer cells have not spread beyond the fibrous tissue. Cancer cells may be found in one nearby lymph node; or

      - The cancer cells have spread from the kidney to a nearby large blood vessel. Cancer cells may be found in one nearby lymph node.

Stage IV is one of the following:

      - The tumor extends beyond the fibrous tissue that surrounds the kidney; or
      - Cancer cells are found in more than one nearby lymph node; or
      - The cancer has spread to other places in the body such as the lungs.

Recurrent cancer is cancer that has come back (recurred) after treatment. It may come back in the kidney or in another part of the body.

 

Treatment

Treatment depends mainly on the stage of disease and the patient's general health and age. People with kidney cancer may have surgery, arterial embolization, radiation therapy, biological therapy, or chemotherapy. Some may have a combination of treatments.

 

At any stage of disease, people with kidney cancer may have treatment to control pain and other symptoms, to relieve the side effects of therapy, and to ease emotional and practical problems. This kind of treatment is called supportive care, symptom management, or palliative care.

 

Because treatment may damage healthy cells and tissues, unwanted side effects are common. These side effects depend mainly on the type and extent of the treatment. Side effects may not be the same for each person, and they may change from one treatment session to the next. Before treatment starts, the health care team will explain possible side effects and suggest ways to help the patient manage them.

 

Surgery

Surgery is the most common treatment for kidney cancer. It is a type of local therapy. It treats cancer in the kidney and the area close to the tumor.

 

An operation to remove the kidney is called a nephrectomy. There are several types of nephrectomies. The type depends mainly on the stage of the tumor. The doctor can explain each operation and discuss which is most suitable for the patient:

 

Radical nephrectomy: Kidney cancer is usually treated with radical nephrectomy. The surgeon removes the entire kidney along with the adrenal gland and some tissue around the kidney. Some lymph nodes in the area also may be removed.

Simple nephrectomy: The surgeon removes only the kidney. Some people with Stage I kidney cancer may have a simple nephrectomy.

Partial nephrectomy: The surgeon removes only the part of the kidney that contains the tumor. This type of surgery may be used when the person has only one kidney, or when the cancer affects both kidneys. Also, a person with a small kidney tumor (less than 4 centimeters) may have this type of surgery.

 

It takes time to heal after surgery, and the time needed to recover is different for each person. Patients are often uncomfortable during the first few days. However, medicine can usually control their pain. Before surgery, patients should discuss the plan for pain relief with the doctor or nurse. After surgery, the doctor can adjust the plan if more pain relief is needed.

 

It is common to feel tired or weak for a while. The health care team watches the patient for signs of kidney problems by monitoring the amount of fluid the patient takes in and the amount of urine produced. They also watch for signs of bleeding, infection, or other problems requiring immediate treatment. Lab tests help the health care team monitor for signs of problems.

 

If one kidney is removed, the remaining kidney generally is able to perform the work of both kidneys. However, if the remaining kidney is not working well or if both kidneys are removed, dialysis is needed to clean the blood. For a few patients, kidney transplantation may be an option. For this procedure, the transplant surgeon replaces the patient's kidney with a healthy kidney from a donor.

 

Arterial embolization

Arterial embolization is a type of local therapy that shrinks the tumor. Sometimes it is done before an operation to make surgery easier. When surgery is not possible, embolization may be used to help relieve the symptoms of kidney cancer.

 

The doctor inserts a narrow tube (catheter) into a blood vessel in the leg. The tube is passed up to the main blood vessel (renal artery) that supplies blood to the kidney. The doctor injects a substance into the blood vessel to block the flow of blood into the kidney. The blockage prevents the tumor from getting oxygen and other substances it needs to grow.

 

After arterial embolization, some patients have back pain or develop a fever. Other side effects are nausea and vomiting. These problems soon go away.

 

Radiation therapy

Radiation therapy (also called radiotherapy) is another type of local therapy. It uses high-energy rays to kill cancer cells. It affects cancer cells only in the treated area. A large machine directs radiation at the body. The patient has treatment at the hospital or clinic, 5 days a week for several weeks.

 

A small number of patients have radiation therapy before surgery to shrink the tumor. Some have it after surgery to kill cancer cells that may remain in the area. People who cannot have surgery may have radiation therapy to relieve pain and other problems caused by the cancer.

 

The side effects of radiation therapy depend mainly on the amount of radiation given and the part of the body that is treated. Patients are likely to become very tired during radiation therapy, especially in the later weeks of treatment. Resting is important, but doctors usually advise patients to try to stay as active as they can.

 

Radiation therapy to the kidney and nearby areas may cause nausea, vomiting, diarrhea, or urinary discomfort. Radiation therapy also may cause a decrease in the number of healthy white blood cells, which help protect the body against infection. In addition, the skin in the treated area may sometimes become red, dry, and tender. Although the side effects of radiation therapy can be distressing, the doctor can usually treat or control them.

 

Biological therapy

Biological therapy is a type of systemic therapy. It uses substances that travel through the bloodstream, reaching and affecting cells all over the body. Biological therapy uses the body's natural ability (immune system) to fight cancer.

 

For patients with metastatic kidney cancer, the doctor may suggest interferon alpha or interleukin-2 (also called IL-2 or aldesleukin). The body normally produces these substances in small amounts in response to infections and other diseases. For cancer treatment, they are made in the laboratory in large amounts.

 

Biological therapy may cause flu-like symptoms, such as chills, fever, muscle aches, weakness, loss of appetite, nausea, vomiting, and diarrhea. Patients also may get a skin rash. These problems can be severe, but they go away after treatment stops.

 

Chemotherapy

Chemotherapy is also a type of systemic therapy. Anticancer drugs enter the bloodstream and travel throughout the body. Although useful for many other cancers, anticancer drugs have shown limited use against kidney cancer. However, many doctors are studying new drugs and new combinations that may prove more helpful.

 

The side effects of chemotherapy depend mainly on the specific drugs and the amount received at one time. In general, anticancer drugs affect cells that divide rapidly, especially:

 

Blood cells: These cells fight infection, help the blood to clot, and carry oxygen to all parts of the body. When drugs affect blood cells, patients are more likely to get infections, may bruise or bleed easily, and may feel very weak and tired.

Cells in hair roots: Chemotherapy can cause hair loss. The hair grows back, but sometimes the new hair is somewhat different in color and texture.

Cells that line the digestive tract: Chemotherapy can cause poor appetite, nausea and vomiting, diarrhea, or mouth and lip sores. Many of these side effects can be controlled with drugs.

 

Follow-up care

Follow-up care after treatment for kidney cancer is important. Even when the cancer seems to have been completely removed or destroyed, the disease sometimes returns because cancer cells can remain in the body after treatment. The doctor monitors the recovery of the person treated for kidney cancer and checks for recurrence of cancer. Checkups help ensure that any changes in health are noted. The patient may have lab tests, chest X-rays, CT scans, or other tests.