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KIDNEY CANCER
Ihor S. Sawczuk, MD
Professor and Vice Chairman of Urology
College of Physicians and Surgeons
Columbia University
WHAT IS A KIDNEY?
A kidney is a bean-shaped organ located toward the back of the body, beneath the rib cage. We have two kidneys, located on either side of our backbone. The primary function of the kidney is to act as a filter to cleanse the blood of waste products. The kidneys are composed of microscopic tubules that function as filtering units. As they filter the blood, the waste products accumulate in fluid, now called urine, which exits the kidneys via long tubes, the ureters, passing into the bladder where it is stored until it is expelled from the body.
Figure 1. Diagram of a kidney
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Figure 1
WHAT IS KIDNEY CANCER?
Kidney cancer is an abnormal growth of the cells lining the tubules of the kidney. Cancers are formed when the cells normally found in our body grow rapidly and without control. The body's normal defenses, formed by the immune system, are unable to destroy the cancer cells because they grow so quickly. As a result, these cells lump together and form a mass, known as a tumor or a cancer. Once a tumor is formed, it can continue to grow uncontrollably and possibly spread beyond the area where it began. Microscopic pieces of tumor can also break off and spread to different locations of the body by way of the blood system or the lymphatic system. This spreading of tumor cells is called metastases.
WHO GETS KIDNEY CANCER?
Renal cell carcinoma is the medical name for the most common form of kidney cancer. Approximately 30,000 new patients with kidney cancer will be diagnosed in the United States in year 2000. Kidney cancer is more common in men than in women, and occurs more commonly in the United States and Canada and Scandinavia. It occurs in both Caucasians and African-Americans. The disease peaks in incidence in the seventh and eighth decades of life, but can be found in men and women under the age of 50.
WHAT CAUSES KIDNEY CANCER?
Many factors have been identified as potential causes of kidney cancer. Some of them include the following: cigarette smoking, which doubles the risk and contributes to as many as one-third of the cases; obesity; high blood pressure and high blood pressure-related medications; occupational exposure to petroleum products, heavy metals, or asbestos; and hormonal imbalances.
HOW CAN I TELL IF I HAVE KIDNEY CANCER? Unfortunately, kidney cancer does not always reveal its presence. Many kidney cancers remain undetected until they become very large simply because there are no clues that specifically point to a correct diagnosis. There currently is no blood or urine test available to detect kidney cancer. However, some warning signs can alert you to the possibility of a kidney cancer. These include blood in the urine (hematuria), a palpable lump in the abdomen, or pain in the side or back that will not go away. People may also feel very tired, lose their appetite, experience weight loss without dieting, have low red blood cell counts (anemia) or even very high red cell counts (polycythemia). Many patients never experience any of these symptoms and have their kidney cancer diagnosed when they are being examined or tested for some other complaint or at their regular annual visit to a doctor.
HOW DO I KNOW IF I HAVE KIDNEY CANCER?
Most of the tests a doctor can order to determine if you do indeed have kidney cancer are radiological imagings.
A special kidney X-ray, called an intravenous pyelogram (IVP), allows the doctor to see the kidney outlines more clearly. It requires injecting a dye into the bloodstream, which then passes through the kidneys and highlights their images.
A CT scan is a sophisticated X-ray that images the organs of the body very closely. This is considered the best test for determining the presence of masses on the kidney.
A renal ultrasound can help distinguish between a solid tumor and a fluid-filled cyst, which does not represent a cancer.
Magnetic resonance imaging (MRI), which uses magnetic waves to image organs in great detail, may also be performed. MRI can be used to check for the presence of tumor in the blood vessels of the kidneys.
A bone scan may be ordered to determine whether the kidney cancer has spread to the bones.
A renal scan can help determine how well the kidneys are functioning.
Blood tests can be performed to look for abnormal levels of creatinine, a sign of impaired kidney functioning, or abnormal levels of liver enzymes, which may suggest that the cancer has involved the liver.
WHAT HAPPENS IF I AM DIAGNOSED WITH KIDNEY CANCER? The "staging" of all cancers is important because it helps to determine the prognosis as well as the type of treatment that would be most beneficial. The stage of the cancer is simply a means of defining the extent of the tumor. The stage reveals whether the cancer is only in the kidney, or whether it has spread outside the organ to other places in the body. In order to stage a cancer, several diagnostic tests may be obtained: a CT scan or MRI of the abdomen, chest, and head; a chest X-ray; a bone scan and blood tests. An arteriogram or venogram, which is a specialized X-ray of the arteries and veins that bring blood to and away from the kidneys, may be performed if it is deemed necessary to study these areas.
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STAGES OF KIDNEY CANCER
Stage I: Cancer is in the kidney only and the size of the tumor is less than or equal to 7.0 cm in diameter. The estimated five-year survival of patients with this stage is over 90 percent.
Stage II: Cancer is in the kidney only and the size of the tumor is greater than 7.0 cm in diameter. The estimated five-year survival of patients with this stage is over 75 percent.
Stage III: The tumor in the kidney may be any size, but does not extend beyond the layer of tissue (Gerota's fascia) that encapsulates the kidney and adrenal gland. Additionally, cancer has spread to the main blood vessel that carries blood away from the kidney (the renal vein), to the blood vessel that carries blood from the lower part of the body to the heart (inferior vena cava), or to the adjacent adrenal gland. The estimated five-year survival of patients with this stage is over 65 percent, depending on involved sites.
Stage IV: Tumor in the kidney extends beyond Gerota's fascia and/or cancer has spread to more than one lymph node near the kidney. Evidence that cancer has spread to other organs in the body, such as the lungs, liver, brain, bones, intestines or pancreas, also indicates Stage IV disease. The estimated five-year survival of patients with this stage is less than 10 percent. HOW IS KIDNEY CANCER TREATED? The stage of the cancer, as well as the age and general health of the patient, help to determine what treatment will be most effective. If the cancer is diagnosed as Stage I, Stage II, or Stage III, the most likely initial treatment will be surgical.
Surgery consists of either a radical nephrectomy, which involves removing the whole kidney and the tissues that surround it, or a partial nephrectomy, where only the area of the kidney that contains the tumor is removed. A radical nephrectomy will not endanger the body's ability to filter waste products, since each person has two kidneys. In fact, many people live healthy lives with only one kidney. If, however, a person's kidney function has already been impaired before being diagnosed with kidney cancer, a partial nephrectomy will most likely be performed. Both radical and partial nephrectomies are performed as "open" surgical procedures. In open surgery, a skin incision is made that allows the surgeon to directly view the anatomy.
Recently, laparoscopic techniques have been utilized in selected cases. Laparoscopic surgery is a minimally invasive technique in which the surgeon views the anatomy and performs the operation using a camera and tools inserted through small holes in the patient's skin. There are advantages and disadvantages to each approach, and several factors determine which technique is best suited for a particular patient. The adrenal gland, which sits above the kidney, may or may not be removed, depending on the individual situation.
For patients with Stage IV cancers or recurrences, there are a variety of treatment options. These include the following:
Surgery: In most cases, surgery alone is not curative in patients with Stage IV cancer and must be accompanied by other forms of medical therapy. However, for select patients potentially curative surgery may be performed to remove the kidney tumor and the distant (metastatic) tumors in other organs during a single operation.
Immunotherapy: Uses the person's own immune system to help fight the cancer. It utilizes materials made by one's body or in a laboratory to boost, direct, or restore natural immune-system defenses against disease. Examples of immunotherapy include Interleukin-2 (IL-2), the only FDA-approved therapy, as well as interferon. Clinical investigations are ongoing at many centers utilizing new and novel applications of immunotherapy in the treatment of kidney cancer. These include vaccine therapies, gene therapies and new drugs. You may want to consider participating in such studies, if available and if you qualify.
Radiation Therapy: Uses X-rays or other high-energy rays to kill cancer cells, thereby preventing them from reproducing. The ultimate goal of radiation is to shrink the tumors. The most common use of radiation therapy is to treat areas where the cancer has spread, such as to bones or the brain, and to relieve pain in these areas.
Chemotherapy: Uses chemicals to damage cancer cells so they cannot multiply. It is given via a pill or via injections into the bloodstream or muscles. The type of chemotherapy that is utilized depends on the site of metastases and the condition of the patient. Chemotherapy alone is not effective in the majority of patients with kidney cancer.
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This article by Dr.Ihor Sawczuk MD, is reproduced from article at BestDoctors.com
Read the complete article at
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