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Bladder Cancer

Bladder tumors can develop on the surface of the bladder wall (benign or malignant papillomas) or grow within the bladder wall (generally more virulent) and quickly invade underlying muscles. Most bladder tumors (90%) are transitional cell carcinomas, arising from the transitional epithelium of mucous membranes. Less common are adenocarcinomas, epidermoid carcinomas, squamous cell carcinomas, sarcomas, tumors in bladder diverticula, and carcinoma in situ. Bladder tumors are most prevalent in men over age 50 and are more common in densely populated industrial areas.

Causes

Certain environmental carcinogens, such as 2-naphthylarnine, benzidine, tobacco, and nitrates, predispose people to transitional cell tumors. Thus, workers in certain industries - rubber workers, weavers, leather finishers, aniline dye workers, hairdressers, petroleum workers, and spray painters -are at high risk for such tumors. The period between exposure to the carcinogen and development of symptoms is about 18 years.

Squamous cell carcinoma of the bladder is most common in geographic areas where schistosomiasis is endemic. It's also associated with chronic bladder irritation and infection (for example, from kidney stones, indwelling urinary catheters, and cystitis caused by cyclophosphamide).

Signs and symptoms

In early stages, approximately 25% of patients with bladder tumors have no symptoms. Commonly, the primary symptom of bladder cancer is blood in the urine (hematuria). Hematuria may be visible to the naked eye (gross) or visible only under a microscope (microscopic) and is usually painless. Other symptoms include frequent urination and pain upon urination (dysuria).

Diagnosis

Only cystoscopy and a biopsy can confirm bladder cancer. Cystoscopy should be performed when hematuria first appears. When it's performed under anesthesia, a bimanual examination is usually done to determine if the bladder is fixed to the pelvic wall. A thorough history and physical examination may help determine whether the tumor has invaded the prostate or the lymph nodes.

The following tests can provide essential information about the tumor:

• Urinalysis can detect blood in the urine and malignant cytology.
• Excretory urography can identify a large, early-stage tumor or an infiltrating tumor, delineate functional problems in the upper urinary tract, assess hydronephrosis, and detect rigid deformity of the bladder wall.
• Retrograde cystography evaluates bladder structure and integrity. Test results help to confirm the diagnosis.
• Pelvic arteriography can reveal tumor invasion into the bladder wall.
• Computed tomography scan reveals the thickness of the involved bladder wall and detects enlarged retroperitoneal lymph nodes.
• Ultrasonography can detect metastasis beyond the bladder and can distinguish a bladder cyst from a tumor.

Treatment

Superficial bladder tumors

Superficial bladder tumors are removed by transurethral (cystoscopic) resection and fulguration (electrical destruction). This procedure is adequate when the tumor hasn't invaded the muscle.

Intravesicular chemotherapy is also used for superficial tumors (especially those that occur in many sites) and to prevent tumor recurrence. This treatment involves washing the bladder directly with antineoplastic drugs - most commonly, thiotepa, doxorubicin, mitomycin, or bacille Calmette-Guerin.

If additional tumors develop, fulguration may have to be repeated every 3 months for years. However, if the tumors penetrate the muscle layer or recur frequently, cystoscopy with fulguration is no longer appropriate.

Tumors too large to be treated through a cystoscope require segmental bladder resection to remove a full-thickness section of the bladder. This procedure is feasible only if the tumor isn't near the bladder neck or ureteral orifices. Bladder instillations of thiotepa after transurethral resection may also help control such tumors.

Infiltrating bladder tumors

Radical cystectomy is the treatment of choice for infiltrating bladder tumors. The week before cystectomy, treatment may include external beam therapy to the bladder. Surgery involves removal of the bladder with perivesical fat,lymph nodes, urethra, the prostate and seminal vesicles (in males), and the uterus and adnexa (in females). The surgeon forms a urinary diversion, usually an ileal conduit. The patient must then wear an external pouch continuously. Other diversions include ureterostomy, nephrostion) possibletomy, vesicostomy, ileal bladder, ileal loop, and sigmoid conduit.

Males are impotent following radical cystectomy and urethrectomy because these procedures damage the sympathetic and parasympathetic nerves that control erection and ejaculation. At a later date, the patient may desire a penile implant to make sexual intercourse (without ejaculation) possible.

Advanced bladder cancer

For patients with advanced bladder cancer, treatment includes cystectomy to remove the tumor, radiation therapy, and systemic chemotherapy with such drugs as cyclophosphamide, fluorouracil, doxorubicin, and cisplatin. This combination sometimes is successful in arresting bladder cancer.

Cisplatin is the most effective single agent.

Investigational treatments

Such treatments include photodynamic therapy and intravesicular administration of interferon alfa and tumor necrosis factor. Photodynamic therapy involves I.V. injection of a photosensitizing agent such as hematoporphyrin ether, which malignant cells readily absorb. Then a cystoscopic laser device introduces laser energy into the bladder, exposing the malignant cells to laser light, which kills them. Because this treatment also produces photosensitivity in normal cells, the patient must totally avoid sunlight for about 30 days.

Prevention

Although bladder cancer can't always be prevented, you can take these steps to help reduce your risk:

• Don't smoke. Not smoking means that cancer-causing chemicals in smoke can't collect in your bladder.
• Drink plenty of fluids. Drinking liquids, especially water, dilutes toxic substances that may be concentrated in your urine and flushes them out of your bladder more quickly.
• If you notice blood in your urine, see your doctor.