More than 70,000 new cases of bladder cancer are diagnosed every year in the United States and about 15,000 people die of bladder cancer every year. About 3 times as many men as women develop bladder cancer. Smoking is the greatest single risk factor and seems to be one of the causes in at least half of all new cases. Certain chemicals that are used in industry can become concentrated in the urine and cause cancer, although exposure to these chemicals is decreasing. These chemicals include hydrocarbons, aniline dyes (such as naphthylamine used in the dye industry) and chemicals used in the rubber, electric, cable, paint, and textile industries. Long-term exposure to some drugs, especially cyclophosphamide, increases the risk of bladder cancer. The chronic irritation that occurs with a parasitic infection called schistosomiasis or with a bladder stone also predisposes people to bladder cancer, although irritation accounts for only a small proportion of all cases.
Most bladder cancers are of a type called transitional cell, affecting the same kinds of cells (transitional cells) that are usually the cancerous cells responsible for renal pelvis and ureter cancers.
Bladder cancer most often causes blood in the urine. Other symptoms may include pain and burning during urination and an urgent, frequent need to urinate. The symptoms of bladder cancer may be identical to those of a bladder infection (cystitis—see see Bladder Infection), and the two problems may occur together. A low blood count (anemia) may cause fatigue, paleness, or both.
The diagnosis is often first suspected when blood is found in the urine. Blood may be detected when a routine microscopic examination of a urine specimen detects red blood cells, or sometimes the urine may be visibly red. Bladder cancer may be suspected if the symptoms of cystitis do not disappear with treatment. Special microscopic evaluation of urine (such as cytology—see Urine cytology) may detect cancer cells. Sometimes bladder cancer is detected when an imaging study such as computed tomography (CT) or ultrasonography is done for another reason.
Most bladder cancers are diagnosed by cystoscopy and biopsy. This examination involves passing a thin, flexible viewing tube through the urethra into the bladder. A small sample of tissue is removed for examination. The person is awake. The urethra is anesthetized somewhat so the procedure is not very uncomfortable.
If the cancer has invaded the bladder muscle, additional testing, including abdominal CT and chest x-ray, are needed to determine whether a cancer has spread.
For cancers that remain on the bladder’s inner surface (superficial tumors) and grow and divide slowly, the risk of death from bladder cancer is less than 5% in the 5 years after diagnosis. The 5-year death rate for tumors that invade the bladder muscle is significantly higher (about 50%). Bladder cancers that have spread beyond the bladder wall (such as to the lymph nodes or other abdominal or pelvic organs) have a much poorer prognosis.
Cancers that are on only the bladder’s inner surface may be removed completely during cystoscopy. However, people commonly develop new cancers later within the bladder. Doctors may be able to prevent the recurrence of these cancers by repeatedly putting anticancer drugs (such as mitomycin C) or bacille Calmette-Guérin (BCG—a substance that stimulates the body’s immune system) into the bladder after all of the cancer has been removed.
Cancers that have grown into the bladder wall cannot be completely removed through a cystoscope. They are usually treated by total or partial removal of the bladder (cystectomy). Radiation therapy alone or in combination with chemotherapy may also be used in an attempt to cure the cancer.
If the entire bladder needs to be removed, doctors must devise a method for the person to be able to drain urine. The usual way has been to route the urine to an opening (stoma) made in the abdominal wall through a passageway made of intestine, called an ileal loop. The urine is then collected in a bag worn on the outside of the body.
Several alternative methods of diverting urine are becoming increasingly common and are appropriate for many people. These methods can be grouped into two categories: an orthotopic neobladder and a continent urinary diversion. In both, an internal reservoir for urine is constructed from the intestine.
For an orthotopic neobladder, the reservoir is connected to the urethra. The person learns to empty this reservoir by relaxing the pelvic floor muscles and increasing pressure within the abdomen, so that urine passes through the urethra very much as it would naturally. Most people are dry during the day, but some urine leakage may occur at night.
For a continent urinary diversion, the reservoir is connected to a stoma in the abdominal wall. A collecting bag is not needed, because the urine remains in the reservoir until the person empties it by inserting a catheter through the stoma into the reservoir, which is done at regular intervals throughout the day.
Cancer that has spread beyond the bladder to the lymph nodes or other organs is treated with chemotherapy. Several different combinations of drugs are active against this type of cancer, particularly when the spread is confined to the lymph nodes. Cystectomy or radiation therapy may be offered to people who respond well to chemotherapy. However, a relatively small number of people are cured. For people who are not cured, efforts are directed at pain relief and end-of-life issues (see Symptoms During a Fatal Illness).