Bladder cancer

Definition

Bladder cancer is a disease in which the cells lining the urinary bladder lose the ability to regulate their growth and start dividing uncontrollably. This abnormal growth results in a mass of cells that form a tumor.

Description

Bladder cancer is the fifth most common cancer in the United States. The American Cancer Society (ACS) estimates that in 1998, approximately 55,000 new cases of bladder cancer will be diagnosed, and it will cause at least 12,500 deaths. The disease is three times more common among men than women, and the incidence also is higher in caucasians.

The urinary bladder is a hollow muscular organ that stores urine from the kidneys until it is excreted out of the body. Two tubes called the ureters bring the urine from the kidneys to the bladder. The urethra carries the urine from the bladder to the outside of the body.

Bladder cancer has a very high rate of recurrence. Even after superficial tumors are completely removed, there is a 75% chance that new tumors will develop in other areas of the bladder. Hence, patients need frequent and thorough follow-up care.

Causes and symptoms

Although the exact cause of bladder cancer is not known, smokers are twice as likely as nonsmokers to get the disease. Hence, smoking is considered the greatest risk factor for bladder cancer. Workers who are exposed to certain chemicals used in the dye industry and in the rubber, leather, textile, and paint industries are believed to be at a higher risk for bladder cancer. The disease also is three times more common in men than in women; caucasians also are at an increased risk. The risk of bladder cancer increases with age. Most cases are found in people who are 50-70 years old. In 2003, studies showed that hormone replacement therapy (HRT), a treatment used by many postmenopausal women, significantly increased the risk of bladder and other cancers.

Frequent urinary infections, kidney and bladder stones, and other conditions that cause long-term irritation to the bladder may increase the risk of getting bladder cancer. A past history of tumors in the bladder also could increase one's risk of getting other tumors.

One of the first warning signals of bladder cancer is blood in the urine. Sometimes, there is enough blood to change the color of the urine to a yellow-red or a dark red. At other times, the color of the urine appears normal but chemical testing of the urine reveals the presence of blood cells. A change in bladder habits such as painful urination, increased frequency of urination and a feeling of needing to urinate but not being able to do so are some of the signs of possible bladder cancer. All of these symptoms also may be caused by conditions other than cancer, but it is important to see a doctor and have the symptoms evaluated. When detected early and treated appropriately, patients have a very good chance of being cured completely.

Diagnosis

If a doctor has any reason to suspect bladder cancer, several tests can help find out if the disease is present. As a first step, a complete medical history will be taken to check for any risk factors. A thorough physical examination will be conducted to assess all the signs and symptoms. Laboratory testing of a urine sample will help to rule out the presence of a bacterial infection. In a urine cytology test, the urine is examined under a microscope to look for any abnormal or cancerous cells. A catheter (tube) can be advanced into the bladder through the urethra, and a salt solution is passed through it to wash the bladder. The solution can then be collected and examined under a microscope to check for the presence of cancerous cells.

A test known as the intravenous pyelogram (IVP) is an x-ray examination that is done after a dye is injected into the blood stream through a vein in the arm. The dye travels through the blood stream and then reaches the kidneys to be excreted. It clearly outlines the kidneys, ureters, bladder, and urethra. Multiple x rays are taken to detect any abnormality in the lining of these organs.

The physician may use a procedure known as a cystoscopy to view the inside of the bladder. A thin hollow lighted tube is introduced into the bladder through the urethra. If any suspicious looking masses are seen, a small piece of the tissue can be removed from it using a pair of biopsy forceps. The tissue is then examined microscopically to verify if cancer is present, and if so, to identify the type of cancer.

If cancer is detected and there is evidence to indicate that it has metastasized (spread) to distant sites in the body, imaging tests such as chest x rays, computed tomography scans (CT), and magnetic resonance imaging (MRI) may be done to determine which organs are affected. Bladder cancer generally tends to spread to the lungs, liver, and bone.

Treatment

Treatment for bladder cancer depends on the stage of the tumor. The patient's medical history, overall health status, and personal preferences also are taken into account when deciding on an appropriate treatment plan. The three standard modes of treatment available for bladder cancer are surgery, radiation therapy, and chemotherapy. In addition, newer treatment methods such as photodynamic therapy and immunotherapy also are being investigated in clinical trials.

Surgery is considered an option only when the disease is in its early stages. If the tumor is localized to a small area and has not spread to the inner layers of the bladder, then the surgery is done without cutting open the abdomen. A cytoscope is introduced into the bladder through the urethra, and the tumor is removed through it. This procedure is called a transurethral resection (TUR). Passing a high-energy laser beam through the cytoscope and burning the cancer may treat any remaining cancer. This procedure is known as electrofulguration. If the cancer has invaded the walls of the bladder, surgery will be done through an incision in the abdomen. Cancer that is not very large can be removed by partial cystectomy, a procedure where a part of the bladder is removed. If the cancer is large or is present in more than one area of the bladder, a radical cystectomy is done. In this operation, the entire bladder and adjoining organs also may be removed. In men, the prostate is removed, while in women, the uterus, ovaries, and fallopian tubes are removed.

If the entire urinary bladder is removed, an alternate place must be created for the urine to be stored before it is excreted out of the body. To do this, a piece of intestine is converted into a small bag and attached to the ureters. This is then connected to an opening (stoma) that is made in the abdominal wall. The procedure is called a urostomy. In some urostomy procedures, the urine from the intestinal sac is routed into a bag that is placed over the stoma in the abdominal wall. The bag is hidden by the clothing and has to be emptied occasionally by the patient. In a different procedure, the urine is collected in the intestinal sac, but there is no bag on the outside of the abdomen. The intestinal sac has to be emptied by the patient, by placing a drainage tube through the stoma.

Radiation therapy that uses high-energy rays to kill cancer cells is generally used after surgery to destroy any remaining cancer cells that may not have been removed during surgery. If the tumor is in a location that makes surgery difficult, or if it is large, radiation may be used before surgery to shrink the tumor. In cases of advanced bladder cancer, radiation therapy is used to ease the symptoms such as pain, bleeding, or blockage. Radiation can be delivered by external beam, where a source of radiation that is outside the body focuses the radiation on the area of the tumor. Occasionally, a small pellet of radioactive material may be placed directly into the cancer. This is known as interstitial radiation therapy.

Chemotherapy uses anticancer drugs to destroy the cancer cells that may have migrated to distant sites. The drugs are introduced into the bloodstream by injecting them into a vein in the arm or taking them orally in pill form. Generally a combination of drugs is more effective than any single drug in treating bladder cancer. Chemotherapy may be given following surgery to kill any remaining cancer cells. It also may be given even when no remaining cancer cells can be seen. This is called adjuvant chemotherapy. Anticancer drugs, including thiotepa, doxorubicin, and mitomycin, also may be instilled directly into the bladder (intravesicular chemotherapy) to treat superficial tumors. A 2003 report stated that giving patients with bladder cancer chemotherapy followed by surgery may improve their outcomes. In the study of 307 patients, those with this combination of therapy lived two years longer than those treated with surgery only.

Immunotherapy, or biological therapy, uses the body's own immune cells to fight the disease. To treat superficial bladder cancer, bacille Calmette-Guerin (BCG) may be instilled directly into the bladder. BCG is a weakened (attenuated) strain of the tuberculosis bacillus that stimulates the body's immune system to fight the cancer. This therapy has been shown to be effective in controlling superficial bladder cancer.

Photodynamic treatment is a novel mode of treatment that uses special chemicals and light to kill the cancerous cells. First, a drug is introduced into the bladder that makes the cancer cells more susceptible to light. Following that, a special light is shone on the bladder in an attempt to destroy the cancerous cells.

New treatments are continuously being investigated. Scientists have made great strides in gene mapping and research in the twenty-first century. In 2003, a type of gene therapy was being tested on patients with bladder cancer with success, but further enhancements were needed.

Prognosis

When detected in early stages, the prognosis for those with bladder cancer is excellent. At least 94% of people survive five years or more after initial diagnosis. However, if the disease has spread to the nearby tissues, the survival rate drops to 49%. If it has metastasized to distant organs such as the lung and liver, commonly only 6% of patients will survive five years or more.

Prevention

Since the exact causes of bladder cancer are not known, there is no certain way to prevent it. Avoiding risk factors whenever possible is the best alternative.

Since smoking doubles one's risk of getting bladder cancer, avoiding tobacco may prevent at least half the deaths that result from bladder cancer. Taking appropriate safety precautions when working with organic cancer-causing chemicals is another way of preventing the disease. Women should discuss the risks vs. benefits of hormone replacement therapy with their physicians.

If a person has had a history of bladder cancer, or has been exposed to cancer-causing chemicals, he or she is considered to be at an increased risk of getting bladder cancer. Similarly, kidney stones, frequent urinary infections, and other conditions that cause long-term irritation to the bladder also increase the chance of getting the disease. In such cases, it is advisable to undergo regular screening tests such as urine cytology, cystoscopy and x rays of the urinary tract, so that bladder cancer can be detected at its early stages and treated appropriately.

Key Terms

Biopsy

The surgical removal and microscopic examination of living tissue for diagnostic purposes.

Chemotherapy

Treatment with anticancer drugs.

Computed tomography (CT) scan

A medical procedure where a series of x rays are taken and put together by a computer in order to form detailed pictures of areas inside the body.

Cystoscopy

A diagnostic procedure where a hollow lighted tube, (cystoscope) is used to look inside the bladder and the urethra.

Electrofulguration

A procedure where a high-energy laser beam is used to burn the cancerous tissue.

Immunotherapy

Treatment of cancer by stimulating the body's immune defense system.

Intravenous pyelogram (IVP)

A procedure where a dye is injected into a vein in the arm. The dye travels through the body and then concentrates in the urine to be excreted. It outlines the kidneys, ureters, and the urinary bladder. An x ray of the pelvic region is then taken and any abnormalities of the urinary tract are revealed.

Magnetic Resonance Imaging (MRI)

A medical procedure used for diagnostic purposes where pictures of areas inside the body can be created using a magnet linked to a computer.

Partial cystectomy

A surgical procedure where the cancerous tissue is removed by cutting out a small piece of the bladder.

Photodynamic therapy

A novel mode of treatment that uses a combination of special light rays and drugs are used to destroy the cancerous cells. First, the drugs, which make cancerous cells more susceptible to the light rays, are introduced into the bladder. Then the light is shone on the bladder to kill the cells.

Radiation therapy

Treatment using high-energy radiation from x-ray machines, cobalt, radium, or other sources.

Radical cystectomy

A surgical procedure that is used when the cancer is in more than one area of the bladder. Along with the bladder, the adjoining organs also are removed. In men, the prostate is removed, while in women, the ovaries, fallopian tubes and uterus may be removed.

Stoma

An artificial opening between two cavities or between a cavity and the surface of the body.

Transurethral resection

A surgical procedure to remove abnormal tissue from the bladder. The technique involves the insertion of an instrument called a cytoscope into the bladder through the urethra, and the tumor is removed through it.

Urostomy

A surgical procedure consisting of cutting the ureters from the bladder and connecting them to an opening (see stoma) on the abdomen, allowing urine to flow into a collection bag.

For Your Information

Resources

Books

• Berkow, Robert, ed. Merck Manual of Diagnosis and Therapy. 16th ed. Rahway, NJ: Merck Research Laboratories, 1992.
• Dollinger, Malin, et al. Everyone's Guide to Cancer Therapy: How Cancer is Diagnosed, Treated, and Managed Day to Day. 3rd ed. Kansas City: Andres & McMeel, 1998.
• Morra, Marion E., and Eve Potts. Choices: The New, Most Up-To-Date Sourcebook for Cancer Information. New York: Avon Books, 1994.
• Murphy, Gerald P., Lois B. Morris, and Dianne Lange. Informed Decisions: The Complete Book of Cancer Diagnosis, Treatment and Recovery. New York: Viking, 1997.

• Grossman, H. Barton, et al. "Neoadjuvant Chemotherapy Plus Cystectomy Compared With Cystectomy Alone for Locally Advanced Bladder Cancer." The New England Journal of Medicine (August 28, 2003): 859.
• "HRT Increases Risk of Gallbladder, Breast, Endometrial, and Bladder Cancer." Women's Health Weekly (July 17, 2003): 31.
• "Intravesical Gene Therapy Appears Safe for Those With Local Bladder Cancer." Cancer Weekly (July 8, 2003): 144.

• American Cancer Society. 1599 Clifton Rd., NE, Atlanta, GA 30329-4251. (800) 227-2345. http://www.cancer.org
• American Foundation for Urologic Disease. 300 W. Pratt St., Suite 401. Baltimore, MD 21201. Phone: (800)-828-7866.
• Cancer Research Institute. 681 Fifth Ave., New York, N.Y. 10022. (800) 992-2623. http://www.cancerresearch.org
• National Cancer Institute. Building 31, Room 10A31, 31 Center Drive, MSC 2580, Bethesda, MD 20892-2580. (800) 422-6237. http://www.nci.nih.gov
• Oncolink. University of Pennsylvania Cancer Center. http://cancer.med.upenn.edu

• "Bladder Cancer." National Cancer Institute Page. http://www.nci.nih.gov
• "1998 Cancer Facts and Figures." American Cancer Society Page. http://www.cancer.orgl

Sources: Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group

The Essay Authors are Lata Cherath, PhD, Teresa G. Odle.