What is bladder cancer?
Related conditions: Kidney cancer
Definition: Bladder cancer is a cancer that forms in the inner lining of the bladder.
Risk factors: Researchers do not completely understand the causes of bladder cancer; however, several carcinogens, family history, and prior diagnosis of bladder cancer remain the chief causes. Smokers are at greatest risk for developing bladder cancer as well as people with exposure to certain chemical dyes in the rubber- and leather-processing, textile, and printing industries.
Etiology and the disease process: The wall of the bladder is lined with cells called transitional cells and squamous cells. More than 90 percent of bladder cancers begin in the transitional cells and are called transitional cell carcinomas. According to the National Cancer Institute, as of 2014 only 2 to 7 percent of bladder cancer patients have squamous cell carcinomas. Cancer that is only in cells in the lining of the bladder is called superficial bladder cancer and often recurs after treatment.
Cancer that begins as a superficial tumor may grow through the lining and into the muscular wall of the bladder. This invasive cancer may extend through the bladder wall into a nearby organ such as the uterus, vagina, or prostate gland or into nearby lymph nodes, in which case cancer cells may have spread to other lymph nodes or other organs such as the lungs and liver or to the bones.
Incidence: Primarily occurring in men and women over the age of forty, bladder cancer is diagnosed in about 53,000 men and about 18,000 women each year in the United States, making it the third most common type of cancer in men, and the eleventh most common in women, according to the National Cancer Institute's statistics for 2014. Caucasians get bladder cancer twice as often as African Americans and Hispanics. People with family members who have bladder cancer as well as people who have previously had bladder cancer are more likely to get the disease.
Symptoms: Bladder cancer often causes no symptoms until it reaches an advanced state that is difficult to cure. The most common symptom of bladder cancer is blood in the urine (hematuria). Some patients experience pain or burning during urination, or a change in urinary habits, such as a frequent urge to urinate.
Screening and diagnosis: Screening tests include a medical interview, a physical examination, urinalysis, urine cytology, and cystoscopy. The urinalysis determines if the urine contains abnormalities such as blood, protein, sugar, and solids. Urine cytology is a microscopic examination of urine to detect any abnormal cells that have sloughed off the bladder wall and have been released in the urine. If necessary, cystoscopy is performed with a very narrow tube with a light and camera inserted through the urethra to examine the inside of the bladder. If bladder cancer is suspected, a physician may order a computed tomography (CT) scan, pyelography, or biopsy. The CT scan is helpful for a three-dimensional view of the bladder and urinary tract to determine if any masses or tumors exist in the bladder or if the cancer has spread to other organs. Pyelography involves injecting a special dye into a vein or the urethra and examining a series of timed-interval X rays of the urinary system to determine if abnormalities exist. The biopsy is typically performed during cystoscopy, and abnormal cells can be detected with a microscope.
Staging refers to the size of the cancer and the extent to which it has invaded the bladder wall and spread to other parts of the body. High-grade tumors are significantly more aggressive and life-threatening than low-grade tumors. Approximately 10 percent of bladder cancer is found to be superficial bladder cancer in situ, which is a highly aggressive, early manifestation of bladder cancer.
Treatment and therapy: The physician may treat superficial bladder cancer with transurethral resection (TUR) by inserting a cystoscope into the bladder through the urethra and using a tool with a small wire loop on the end to remove the cancer and to burn away any remaining cancer cells with an electric current. For invasive bladder cancer or cancer involving a large portion of the bladder, surgery is performed to remove the entire bladder, nearby lymph nodes, part of the urethra, and the nearby organs that may contain cancer cells. In some cases of low-grade cancer, only part of the bladder is removed in a procedure called segmental cystectomy.
Radiation therapy uses high-energy rays to kill localized cancer cells to shrink the tumor before surgery or if surgery is not an option. Chemotherapy uses one drug or a combination of drugs to kill cancer cells. Superficial bladder cancer can be treated with local chemotherapy; once per week for several weeks; a catheter is inserted through the urethra and remains in the bladder for several hours. If the cancer has deeply invaded the bladder or spread to lymph nodes or other organs, chemotherapy may be used to treat the entire body.
Biological therapy, or immunotherapy, uses the body’s natural immune system to fight cancer by inserting a catheter with a solution containing live, weakened bacteria to kill cancer cells in the bladder.
Prognosis, prevention, and outcomes: Bladder cancer has one of the highest recurrence rates of all cancers. If treated once, patients must continue a course of follow-up screenings. The five-year survival rate for patients with Stage 0 bladder cancer is 98 percent, according to the American Cancer Society in 2014. Most patients with bladder cancer will be diagnosed with a superficial tumor. As of 2014, the American Cancer Society also reports that patients in each of the remaining stages have five-year survival rates as follows: Stage I, 88 percent; Stage II, 63 percent; Stage III, 46 percent; and Stage IV, 15 percent.
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