What is bladder cancer?
Bladder cancer occurs when there are abnormal, cancerous cells growing in the bladder. The American Cancer Society (ACS) estimated 73,000 diagnosed cases of bladder cancer in 2013.
Bladder cancer affects men about 3 times more often than women, and it occurs in whites twice as often as in African-Americans. The risk of bladder cancer increases with age—over 90 percent of people who are diagnosed with it are older than 55.
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The bladder is a triangle-shaped, hollow organ located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to 2 cups of urine for 2 to 5 hours.
Urinary tract of male (left) and female (right). Click to Enlarge
What are the different types of bladder cancer?
There are several types of bladder cancers, including the following:
Transitional cell (urothelial) carcinoma. Transitional cell carcinoma is cancer that begins in the cells lining the inside of the bladder. Transitional cells also line the other parts of the urinary tract including the kidneys, ureters, and urethra. Transitional cell carcinoma is the most common kind of bladder cancer, occurring in about 95% of cases.
Squamous cell carcinoma. Squamous cell carcinoma is cancer that begins in squamous cells—thin, flat cells found in the tissue that resemble the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. About 1% to 2% of bladder cancers are squamous cell carcinomas.
Adenocarcinoma. Adenocarcinoma is cancer that begins in the cells of glandular structures lining certain organs in the body. Adenocarcinomas account for only about 1% of bladder cancers.
What causes bladder cancer?
While the exact causes of bladder cancer are not known, there are well-established risk factors for developing the disease. Risk factors for bladder cancer include the following:
Cigarette smoking. Cigarette smoking is a major risk factor for developing bladder cancer. Smoking causes about half of the deaths from bladder cancer among men, and less than one-third of bladder cancer deaths in women. The disease occurs in smokers twice as often as nonsmokers. Quitting smoking reduces the risk of bladder cancer, as well as several other types of cancer and diseases.
Occupational exposure. Certain occupations and work environments that expose workers to dyes and some organic chemicals appear to increase the risk for bladder cancer. Workers in the rubber, chemical, leather, textile, metal, and printing industries are exposed to substances such as aniline dye and aromatic amines that may increase their risk for bladder cancer. Other at-risk occupations include hairdressers, machinists, painters, and truck drivers (due to exposure to diesel fumes).
Chronic bladder irritation. Chronic bladder infections or bladder stones may be linked to certain types of bladder cancer.
Age. The risk for bladder cancer increases with age. According to the ACS, the average age at the time of diagnosis is 73, and 9 out of 10 people are diagnosed after age 55.
Gender. Bladder cancer occurs about 3 times more often in men than in women.
Race. Whites are twice as likely to develop bladder cancer as African-Americans and Hispanics. Asians have the lowest bladder cancer rates.
Personal history of bladder cancer. Individuals who have previously had bladder cancer have an increased risk of developing the disease again.
Family history. Individuals with family members who have had bladder cancer are more likely to develop the disease. Research is ongoing to determine specific genetic risks for bladder cancer.
Parasite infections. Infection with certain parasites found in tropical regions of the world, but not in the U.S., increases the risk of bladder cancer.
What are the symptoms of bladder cancer?
The following are the most common symptoms of bladder cancer. However, each individual may experience symptoms differently. Symptoms may include:
Visible blood in the urine
Microscopic hematuria. The presence of red blood cells in the urine that cannot be seen with the naked eye.
Urgency. Frequently feeling the need to urinate without results.
Pelvic or flank pain
The symptoms of bladder cancer may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.
How is bladder cancer diagnosed?
In addition to a complete medical history and physical examination, your doctor may order some of the following procedures for bladder cancer diagnosis or staging:
Rectal or vaginal examination. The doctor can check for the presence of tumors large enough to be felt.
Cystoscopy (also called cystourethroscopy). An examination in which a scope, a flexible tube and viewing device, is inserted through the urethra to examine the bladder and urinary tract for structural abnormalities or obstructions, such as tumors or stones. Samples of the bladder tissue (called a biopsy) may be removed through the cystoscope for examination under a microscope in the laboratory.
Intravenous pyelogram (IVP). A series of X-rays of the kidney, ureters, and bladder with the injection of a contrast dye into the vein. This test is used to detect tumors, abnormalities, kidney stones, or any obstructions, and to assess renal blood flow. It may also be used to rule out other diseases or check for spread (metastasis) of the bladder cancer to other areas of the urinary tract.
Laboratory tests. Tests may be performed on the urine to check for blood, chemicals, bacteria, and cells. The urine may be examined microscopically or grown in culture to check for infection. Cancerous cells may be detected using the microscope.
Bladder tumor marker studies. Tests to determine cellular characteristics and markers or substances released by bladder cancer cells into the urine.
Ultrasound (also called sonography). A diagnostic imaging technique that uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function and to assess blood flow through various vessels.
Computed tomography scan (also called a CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
Positron emission tomography (PET). A PET scan may show areas of cancer that may not be seen on a CT scan or an MRI scan.
Bladder biopsy. A procedure in which tissue samples are removed (with a needle or during surgery) from the bladder for examination under a microscope to determine if cancer or other abnormal cells are present.
Once bladder cancer is diagnosed, your doctor will determine the grade and stage of the cancer:
Grade. This differentiates the cells from normal tissue and estimates the rate of cancer growth
Stage. This indicates the extent the cancer has spread and if other body parts or organs are affected. Additional tests may be needed to determine if bladder cancer is limited to the bladder or if it has spread
The American Joint Committee on Cancer provides guidelines for staging of bladder cancer. The stages range from Stage 0 to Stage IV and have detailed criteria for tumor size, invasiveness, presence in lymph nodes, and whether or not the cancer has metastasized (spread) to other organs. A general description of each stage of bladder cancer follows:
Stage 0. Cancer cells are found only on the inner lining of the bladder. This is also called superficial cancer or carcinoma in situ.
Stage I. Cancer cells are found deep in the lining of the bladder, but have not invaded the bladder muscle.
Stage II. Cancer cells are present in the muscle of the bladder.
Stage III. Cancer cells have spread through the bladder muscle into the tissues around the bladder, such as the prostate in men or the uterus in women.
Stage IV. Cancer has progressed further into the abdominal cavity, and may have spread to lymph nodes and other organs in the body.
What is the treatment for bladder cancer?
Specific treatment for bladder cancer will be determined by your doctor based on:
Your age, overall health, and medical history
Extent of the disease
Grade and stage of the cancer
Your tolerance of specific medicines, procedures, or therapies
Expectations for the course of the disease
Your opinion or preference
Most individuals with bladder cancer have superficial and noninvasive tumors. Treatment for these tumors is often very effective with an excellent prognosis. The remainder of bladder cancers invade deep into the bladder wall and muscle. There is a greater risk for metastasis into other tissues in these cases. Depending on the extent, bladder cancers may be managed with a single therapy or combination of treatments.
Treatment may include:
Radiation therapy. Radiation therapy uses high-energy rays to kill or shrink cancer cells. Internal or external radiation, or both, may be used in the treatment of bladder cancer. With internal radiation, a radiation implant is placed into the bladder for a direct effect on cancer cells. External radiation uses a machine outside the body to direct rays at a broader area. Radiation therapy for bladder cancer may have side effects including nausea, vomiting, diarrhea, and urinary discomfort, and may affect sexual function in both men and women.
Chemotherapy. Chemotherapy uses anticancer drugs to kill cancer cells. Chemotherapy may be given internally by placing the drugs directly in the bladder, called intravesical chemotherapy. It may also be given systemically, to affect cancer cells throughout the body. Like other chemotherapy drugs, those used to treat bladder cancer may have side effects that may include hair loss, nausea, vomiting, bruising, and fatigue. Other side effects include mouth sores, an increased risk of infections, and possible kidney damage. Drugs used directly in the bladder may cause irritation or bleeding.
Biological therapy. Biological therapy uses the body's own immune system to fight cancer. In one form of this therapy, a solution called Bacillus Calmette-Guerin is placed in the bladder, where it stimulates the immune system to kill the cancer cells.
Clinical trials. Clinical trials and research studies are underway to evaluate new therapies. Some of these include photodynamic therapy, which involves the use of light to kill cancer cells, and the use of interferon as an anticancer agent.
The long-term prognosis for individuals with bladder cancer depends on the size of the tumor, lymph node involvement, and degree of metastasis (spreading) at the time of diagnosis. Sometimes superficial bladder cancers recur locally in the bladder, at the site of original diagnosis, or at other places in the bladder. These recurrent tumors are evaluated and treated the same way as the original cancer. However, if the tumor continues to return, eventually a cystectomy will be required. But, tumors that recur in distant sites may require other treatments, such as chemotherapy or radiation therapy.
Can bladder cancer be prevented?
While there is no known way to prevent bladder cancer, you can reduce your chances of developing the disease. The ACS offers the following recommendations:
Do not smoke.
Avoid occupational exposure to certain chemicals.
Drink plenty of liquids. This may limit the time that cancer-causing substances present in urine will remain in contact with bladder cells.
Eat plenty of fruits and vegetables.