Kidney Cancer (Renal Cancer)

Kidney cancer: Cancer that forms in tissues of the kidneys. Kidney cancer includes renal cell carcinoma (cancer that forms in the lining of very small tubes in the kidney that filter the blood and remove waste products) and renal pelvis carcinoma (cancer that forms in the center of the kidney where urine collects). It also includes Wilms tumor, which is a type of kidney cancer that usually develops in children under the age of 5.

Estimated new cases and deaths from kidney (renal cell and renal pelvis) cancer in the United States in 2009:

 
  New cases: 49,096
 
 
  Deaths: 11,033

 
 The Kidneys

The kidneys are a pair of organs on either side of the spine in the lower abdomen. Each kidney is about the size of a fist. Attached to the top of each kidney is an adrenal gland. A mass of fatty tissue and an outer layer of fibrous tissue (Gerota's fascia) enclose the kidneys and adrenal glands.
 
 The kidneys are part of the urinary tract. They make urine by removing wastes and extra water from the blood. Urine collects in a hollow space (renal pelvis) in the middle of each kidney. It passes from the renal pelvis into the bladder through a tube called a ureter. Urine leaves the body through another tube (the urethra).

The kidneys also make substances that help control blood pressure and the production of red blood cells.

Tumors can be benign or malignant:

Benign tumors are not cancer:

Benign tumors are rarely life threatening.
Usually, benign tumors can be removed, and they seldom grow back.
Cells from benign tumors do not invade tissues around them or spread to other parts of the body.

Malignant tumors are cancer:

Malignant tumors are generally more serious than benign tumors. They may be life threatening.
Malignant tumors often can be removed, but they can grow back.
Cells from malignant tumors can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system. That is how cancer cells spread from the original cancer (primary tumor) to form new tumors in other organs. The spread of cancer is called metastasis.

Several types of cancer can start in the kidney. 

This type is sometimes 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.

When kidney cancer spreads outside the kidney, cancer cells are often found in nearby lymph nodes. Kidney cancer also may spread to the lungs, bones, or liver. And it may spread from one kidney to the other.

When cancer spreads (metastasizes) from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if kidney cancer spreads to the lungs, the cancer cells in the lungs are actually kidney cancer cells. The disease is metastatic kidney cancer, not lung cancer. It is treated as kidney cancer, not lung cancer. Doctors sometimes call the new tumor metastatic or "distant" disease.

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: 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. People who think they may be at risk should discuss this concern with their doctor. The doctor may be able to suggest ways to reduce the risk and can plan an appropriate schedule for checkups.

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.

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 2 3/4 inches (7 centimeters). 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 2 3/4 inches. 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

Many people with kidney cancer want to take an active part in making decisions about their medical care. They want to learn all they can about their disease and their treatment choices. However, shock and stress after the diagnosis can make it hard to think of everything they want to ask the doctor. It often helps to make a list of questions before an appointment. To help remember what the doctor says, people may take notes or ask whether they may use a tape recorder. Some also want to have a family member or friend with them when they talk to the doctor—to take part in the discussion, to take notes, or just to listen.

The doctor may refer the patient to a specialist, or the patient may ask for a referral. Specialists who treat kidney cancer include doctors who specialize in diseases of the urinary system (urologists) and doctors who specialize in cancer (medical oncologists and radiation oncologists).

Getting a Second Opinion

Before starting treatment, a person with kidney cancer might want a second opinion about the diagnosis and the treatment plan. Some insurance companies require a second opinion; others may cover a second opinion if the patient or doctor requests it.

Preparing for Treatment

Treatment depends mainly on the stage of disease and the patient's general health and age. The doctor can describe treatment choices and discuss the expected results. The doctor and patient can work together to develop a treatment plan that fits the patient's needs.

Methods of Treatment

People with kidney cancer may have surgery, arterial embolization, radiation therapy, biological therapy, or chemotherapy. Some may have a combination of treatments.

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 or three-quarters of an inch) may have this type of surgery.

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.

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.

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.

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 section on "The Promise of Cancer Research" has more information about these studies.

Side Effects of Cancer Treatment

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

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

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

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 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

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.

Source: NCI (National Cancer Institute)