Major Forms of Cancer - Bladder cancer

As with stomach cancer, the incidence of cancer of the bladder rises progressively with age and occurs much more frequently in men than in women. Extensive occurrence of bladder cancer is commonly associated with industrial growth, but internationally its incidence ranges from a high rate in England to a low one in Japan; in the United States, the highest incidence of bladder cancer is in southern New Jersey. A study by the Roswell Park Memorial Institute, a cancer research center in Buffalo, New York, found that persons of Italian-American parentage were more likely to have bladder cancer than those of different parentage, and that women living in urban areas were more likely to develop the disease than their country cousins. American blacks have less bladder cancer than American whites.

Bladder cancer appears at an annual rate of about 40,000 new cases each year in the United States and causes more than 15,000 deaths annually.

Symptoms

A change in bladder habits is among the first signs of bladder cancer. The change might be the presence of pain while urinating, a noticeable difficulty in urinating, or a difference in the frequency of urination.

Another symptom of the disease is the appearance of blood in the urine. The degree of blood coloration is not necessarily related to the severity of the cancer; any sign of blood in the urine should be investigated. Nor should the absence of pain be allowed to minimize the seriousness of urinary bleeding as a symptom of a diseased bladder. Even without pain, the presence of blood can indicate a problem such as an obstruction to the urinary flow that can lead to uremia, a toxic condition caused by retention of urinary waste products in the system.

Detection

Cancer of the bladder is frequently diagnosed from common signs and symptoms, particularly the appearance of blood in the urine. A laboratory examination of the patient's urine may also reveal the presence of cancer cells that have been washed out of the bladder. The disease can be detected by apyelogram —a kind of X-ray picture made by filling the urinary system with a fluid that makes tissue details appear in sharp contrast—and by examination of the membrane lining the bladder. The bladder lining may be examined by surgical biopsy or by cystoscopy , the viewing of the interior of the bladder by means of a device inserted in the urethra—or both.

Examination of the bladder lining is needed to determine the type of tumor that may be the cause of the symptoms. One type, called a papillary tumor , or papilloma , is relatively harmless and usually does not invade the wall of the bladder as does the more dangerous type, sometimes described as a solid lesion. The degree of invasion of the bladder tissues by the infiltrating mass determines the type of treatment recommended. However, any tumor found in the lining of the bladder must be removed, because the papillary type can progress into a solid lesion if not treated.

Therapy

The cure of a bladder tumor can be approached in several ways, the choice of treatments depending upon the size and type of growth, the location of the tumor, and so on. Chemotherapy, using drugs such as thiotepa, has been successful in treating papillary bladder tumors; the chemical is applied directly to the bladder lining. A kind of electric cautery known as fulguration also may be used to destroy the tissue growth; it may be employed by cystoscopy or as part of a surgical approach. Radiation therapy also may be used by implanting radium needles in the affected bladder tissue. Surgical excision of the cancerous area, with or without radiation, chemotherapy, or cautery, may be the procedure chosen. In advanced cases of bladder cancer, the bladder may be removed and its function performed by the construction of a substitute organ from other tissues or by the relocation of the upper ends of the ureters at other urine-collecting points.

Causes

Cancer of the bladder may be caused by irritation from bladder stones or by toxic chemicals excreted from the kidneys. A high incidence of bladder cancer has been found among persons who are heavy cigarette smokers; a possible explanation is that certain carcinogenic tobacco-burning byproducts are absorbed into the blood and excreted through the kidneys. The evidence includes studies showing that when such patients quit smoking, the carcinogens no longer appear in their urine.

Occupational factors have been associated with cancer of the bladder since 1895, when it was discovered that persons who worked with aniline chemical dyes were among those most likely to develop the disease. The incidence of the disease among chemical workers was found to be 30 times greater than that of the general population. The aniline dye workers developed bladder cancer at an average age 15 years younger than among the general population. The effect of the chemical dyes was verified by the development of cancer in the bladders of laboratory animals exposed to the dyes. In recent years, it has been found that many other chemicals can cause bladder cancer.

Besides the influence of industrial environmental factors, bladder cancer is associated with schistosomiasis , a disease occurring in Africa, Asia, South America, and other regions. Schistosomiasis develops after bathing or wading in water infested by a blood fluke. The organisms penetrate the skin and migrate to the intestines or urinary bladder, producing an inflammation that eventually leads to cancer. See Ch. 19, Other Diseases of Major Importance , for a fuller description of the disease.