Bladder cancer strikes 38,000 men and 15,000 women annually in the U.S. These statistics make it the fourth most common cancer in men and eighth most common in women. Fortunately, it is a highly treatable cancer, especially when detected early. Approaches to treatment include chemotherapy, biological therapy, radiation therapy and a number of surgical procedures. The best treatment is determined by the individual and the nature of his or her cancer.
Epidemiology is the characterization of a disease as it affects populations. It identifies those who may be susceptible and the risk factors that influence the disease’s occurrence. The incidence has already been noted. Risk factors include age, race, gender, family medical history, personal medical history, environmental factors and smoking. Of all these, smoking poses the greatest risk.
Age is a factor. The cancer is relatively rare in people under age 40 (less than 1% of cancers) but appears more frequently in those 60 and older. Most bladder cancers are diagnosed in people in their late 60s. Whites are 1.5 times more likely to develop the cancer than other races. Asians are at the least risk. Men are more than twice as likely as women to develop bladder cancer. People whose families have a history of bladder cancer are at greater risk. These people do not inherit the cancer. Rather they inherit a certain susceptibility to the disease. Chronic urinary infection, kidney and bladder stones, and chronic bladder infections tend to raise the risk of bladder cancer. Environmental factors, such as arsenic in drinking water, and chemicals involved in specific occupations increase risks. The cancer is seen more frequently in hairdressers, machinists, printers, painters, truck drivers and people who work in rubber, chemical, textile, metal and leather industries. The Chinese herb Aristolochia fan gchi contained in some diet pills has been tied to both kidney failure and bladder cancers.
Smoking creates the greatest risk. The National Cancer Institute estimates that smoking may be responsible for 48% of bladder cancer deaths among men and 28% of such deaths among women.
The urinary tract consists of two kidneys, two ureters which drain urine from the kidneys into the bladder for storage, and the urethra which drains the bladder. The bladder is surrounded by lymph nodes, small specialized organs which feed cells with immune system functions into the blood stream. In women, the uterus lies just behind the bladder. In men, the prostate lies at the base of the bladder. All these organs can be affected by the cancer and some of the procedures employed to treat it. The bladder wall is made of four layers: the inner layer (mucosa), a basement membrane or layer of connective tissue (lamina propria), a wall of muscle (detrussor muscle), and an outer layer of perivesicle fat (serosa).
Blood in the urine (hematuria) is a symptom of bladder cancer and other diseases. It may be gross hematuria (visible to the naked eye) or visible only under a microscope. Other symptoms include frequent urination or pain upon urination. Flank pain is also a symptom. These symptoms can appear with a host of illnesses such as urinary tract infections, benign tumors, bladder stones and others. The diagnostic procedure is designed to identify specific causes and eliminate others
Diagnosis begins with a discussion of the patient’s medical history. This is followed by a physical exam in which the doctor will feel the abdomen and pelvis for any physical signs that suggest tumors. The doctor may also include a rectal or vaginal exam.
Study of a urine sample will determine if blood or cancer cells are present. In some cases the doctor will order an intravenous pyelogram. A harmless dye is injected into a vessel. The dye collects temporarily and improves the quality of the x-rays that follow. Other imaging technologies such as computed tomography (CT) and magnetic resonance imaging (MRI) may be employed.
Cytoscopy is common. This involves threading a thin tube through the urethra into the bladder. Miniaturized fiber optics provide light to allow the doctor to examine the bladder from within the cavity. Other miniaturized technology in the tube allows him to gather minute tissue samples that will be sent to a pathologist who will study them for the presence of cancer cells.
Tumors may take different forms. Superficial urothelial tumors may or may not be invasive. They seldom spread deeply into the bladder wall. Papillary urothelial tumors are slender projections resembling the arm of a cactus that grow from the bladder wall toward the center of the bladder. Those that grow only toward the center are called noninvasive papillary urothelial tumors.
Papillary urothelial carcinoma is an abnormal papillary tumor. Its cells have irregular sizes, shapes and arrangements. When these abnormalities are slight, the tumor is called "low grade." They seldom invade the bladder wall but often return following removal. The risk of bladder wall invasion is greater when cells in these tumors show greater abnormal characteristics. Flat urothelial tumors (carcinoma in situ or CIS) affect only the cells in the interior bladder lining. In the great majority of instances, these cancers are limited to the lining. When they invade the muscle layer they are called flat invasive urothelial carcinomas.
These tumors are usually removed by simple surgical procedures such as transurethral resection of the bladder (TURBT). These tumors can recur in the bladder or elsewhere in the urinary tract. Patients who have urothelial tumors removed undergo re-examinations at regular intervals to check for recurrence. However patients who have more aggressive muscle invasive tumors will require more radical surgery and treatment.