Atlas of pathophysiology, 2 Edition

Part II - Disorders

Bladder Cancer

Cancer of the bladder is the most common cancer of the urinary tract.

Workers in certain industries (rubber workers, weavers and leather finishers, aniline dye workers, hairdressers, petroleum workers, and spray painters) are at high risk for bladder cancer. The period between exposure to the carcinogen and development of symptoms is about 18 years.

Age Alert

Bladder tumors are most prevalent in men over age 50 and are most common in densely populated industrial areas.

Causes

Primary cause unknown

Predisposing factors

·   Transitional cell tumors—certain environmental carcinogens, including 2-naphthylamine, benzidine, tobacco, nitrates

·   Squamous cell carcinoma of the bladder:

§  chronic bladder irritation or infection; for example, from kidney stones, indwelling urinary catheters, cystitis from cyclophosphamide

§  schistosomiasis

Pathophysiology

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. Ninety percent of bladder tumors 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.

Signs and symptoms

·   In early stages, no symptoms in approximately 25% of patients

·   First sign: gross, painless, intermittent hematuria (in many cases with clots in the urine)

·   Invasive lesions: suprapubic pain after voiding

·   Other signs and symptoms:

§  bladder irritability, urinary frequency

§  nocturia

§  dribbling

Diagnostic test results

·   Cystoscopy and biopsy confirm bladder cancer diagnosis.

·   Excretory urography identifies a large, early-stage tumor or an infiltrating tumor; delineates functional problems in the upper urinary tract; assesses hydronephrosis; and detects rigid deformity of the bladder wall.

·   Retrograde cystography evaluates bladder structure and integrity and also helps confirm bladder cancer diagnosis.

·   Bone scan detects metastases.

·   Computed tomography scan defines the thickness of the involved bladder wall and discloses enlarged retroperitoneal lymph nodes.

·   Ultrasonography finds metastases in tissues beyond the bladder and distinguishes a bladder cyst from a bladder tumor.

·   Complete blood count detects anemia.

·   Urinalysis detects blood and malignant cells in the urine.

Treatment

Superficial bladder tumors

·   Transurethral cystoscopic resection and fulguration (electrical destruction); adequate when the tumor hasn't invaded the muscle

·   Intravesicular chemotherapy; useful for multiple tumors (especially those that occur in many sites) and to prevent tumor recurrence

·   If additional tumors develop:

§  fulguration every 3 months

§  more radical therapy if tumors penetrate the muscle layer or recur frequently

Larger tumors

·   Segmental bladder resection to remove a full-thickness section of the bladder; only if tumor isn't near the bladder neck or ureteral orifices

·   Instillation of thiotepa after transurethral resection

Infiltrating bladder tumors

·   Radical cystectomy—removal of the bladder with perivesical fat, lymph nodes, urethra, and prostate and seminal vesicles or uterus and adnexa

·   Possibly, preoperative external beam therapy to bladder

·   Urinary diversion, usually an ileal conduit (patient must then wear an external pouch continuously)

·   Possible later penile implant

Advanced bladder cancer

·   Cystectomy to remove tumor

·   Radiation therapy

·   Systemic chemotherapy:

§  cyclophosphamide, fluorouracil, doxorubicin, cisplatin combination may arrest bladder cancer

§  cisplatin most effective single agent

Investigational treatments

·   Photodynamic therapy:

§  I.V. injection of a photosensitizing agent such as hematoporphyrin ether, which malignant cells readily absorb, followed by cystoscopic laser treatment to kill malignant cells

§  treatment also renders normal cells photosensitive (patient must totally avoid sunlight for about 30 days)

·   Intravesicular administration of interferon alfa and tumor necrosis factor

P.355

BLADDER TUMOR

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