50 per cent of all cases of bladder cancer are caused by smoking.
What is the Bladder?
The bladder is an organ in the lower abdomen that stores urine after it is released from the kidneys until it is passed out of the body.
What is bladder cancer?
Bladder cancer is the result of cell changes in the mucous (inside) wall of the bladder. It is caused by changes in the cells' chromosomes or DNA (deoxyribonucleic acid). This form of cancer develops most often in people between the ages of 60 and 79, with the average age being 67. The disease is three times more common in men than in women. It is one of the most common forms of cancer to strike men.
How does bladder cancer develop?
In most cases, bladder cancer is caused by external factors. Cigarette smoking (because of harmful chemicals within the cigarette) and exposure to some carcinogenic (cancer causing) agents such as aromatic compounds and chemicals used in industry and elsewhere can lead to bladder cancer.
Approximately 50 percent of all cases are caused by tobacco smoking and 10 per cent by job-related factors.
Cigarette smoking is the largest risk factor for bladder cancer. Smokers have 2-4 times the risk of having bladder cancer, and it contributes to up to 50% of all bladder cancers that are diagnosed.
In the tropics, bladder cancer is often brought about by the widespread disease bilharziasis (river blindness), which is caused by a tiny micro-organism that invades the bladder.
Other risk factors known are from occupational exposures, such as polychromatic hydrocarbons (benzene, benzidine).
A group of chemicals called arylamines are known to cause bladder cancer. These chemicals have been banned in developed countries for about 20 years. But it can take up to 25 years for a bladder cancer to develop. You may have been exposed to them a long time ago if you work in industries such as rubber or plastics manufacture. Arylamines that increase risk of bladder cancer include
- Aniline dyes
- 2-Naphthylamine
- 4-Aminobiphenyl
- Xenylamine
- Benzidine
- O-toluidine
Another group of chemicals called polycyclic hydrocarbons increase the risk of bladder cancer. Exposure to these chemicals is possible in industries where people handle carbon or crude oil, or substances made from them. You may also come into contact with them in any industry involving combustion, such as smelting.
Some other jobs have been linked to an increased risk of bladder cancer. These include
- Bus drivers
- Metal casters, machine setters and operators
- Leather workers
- Blacksmiths
- Hairdressers
- Mechanics
- Miners
- Painters
In all these occupations the increase in risk of bladder cancer is less than 30%.
Other risk factors
· Race. Caucasians are about twice as likely to develop bladder cancer as compared with African American and Latino populations. The reason for this difference is not well understood. People of Asian descent have the lowest incidence of bladder cancer.
· Increasing Age. The risk of bladder cancer increases with age. Over 70% of people with bladder cancer are older than 65 years old.
· Gender. Men get bladder cancer at a rate 4 times greater than women.
- Genetics. Bladder cancer is common within some families. This may account for 1% of all cases. People with a mutation of the retinoblastoma gene, which causes them to develop cancer of their eye as infants, have a higher rate of bladder cancer. Many studies have found people differ in their ability to break down chemicals in their body and this is determined by certain genes they inherit. People who inherit genes that lead to slow breakdown of chemicals are more likely to develop bladder cancer.
- Diabetes. People who have type 2 diabetes have a 40% increase in their risk of developing bladder cancer.
- Fluid consumption. Low fluid consumption increases risk. People who drink a lot of fluids each day have a lower rate of bladder cancer. This is thought to be because they empty their bladders often. By doing this, they keep chemicals from lingering in their bodies.
- Diet. A healthy diet may lower your risk of bladder cancer. Some studies seem to show that eating as little as 100 grams of fruit a day (about 4 ounces) can significantly lower your bladder cancer risk, but some other studies show no reduction in risk. High beta-carotene levels in the diet have been shown in one study to reduce bladder cancer risk in people who smoke. Selenium is a nutrient found in various foods and has also been shown to protect against bladder cancer in some studies.
- Alcohol. One study has shown that people who drank large amounts of alcohol had a lower bladder cancer risk, especially if they passed urine often. But another study showed that drinking alcohol did not reduce risk, apart from beer. It is important to remember though that alcohol increases the risk of several other cancers, including breast and bowel cancer.
- Early menopause. Two studies show that women who have an early menopause (before the age of 42 to 45) have their risk of bladder cancer increased by at least half compared to women who have their menopause at the age of 48 or later. The risk increases by the same amount in women who have both their ovaries removed for medical reasons.
What are the symptoms of bladder cancer?
- By far the most common sign of bladder cancer is the presence of blood in the urine, called hematuria. The blood in the urine can either be noticeable by the naked eye, called gross hematuria, or noted only when the urine is analyzed in a laboratory, called microscopic hematuria.
- Other signs of bladder cancer could include symptoms of a urinary tract infection. These include increased frequency of urination, a feeling of urgency to urinate, pain (burning) with urination, and the feeling of incomplete bladder emptying. These are all caused by irritation of the bladder wall by the tumor
- In advanced cases of bladder cancer, the tumor can actually obstruct either the entrance of urine into the bladder or the exit of urine from the bladder. This causes severe flank pain, infection, and damage to the kidneys. Obviously, bladder cancers that cause these symptoms need to be dealt with immediately
Smoking and bladder cancer
- Risk of bladder cancer increases with age, and men are more commonly affected than women.
- Recent research in Spain showed current smoking increased the risk of bladder cancer by more than seven-fold in men and by roughly five-fold in women. Other researches confirm the huge risk of smoking for the bladder cancer development as well.
- Former smokers also had an increased risk of bladder cancer. Risk of bladder cancer increased with duration and amount smoked.
- Stopping smoking, even after many years, can be beneficial, as ex-smokers have a lower rate of bladder cancer than those who continue to smoke.
- Compared to men who inhaled into the mouth, men who inhaled into the throat or chest had an increased risk of bladder cancer.
How is bladder cancer diagnosed?
If blood is discovered in the urine or there are constant symptoms of bladder irritation of unknown cause, the patient should be examined by a doctor. In order to reach a diagnosis your family doctor will refer the patient urgently to the local hospital urology department for a series of special examinations. If a tumor is suspected, a procedure called a cystoscopy, is necessary, in which a doctor looks up into the bladder via the urethra using an instrument called a cystoscope.
In addition, ultrasound scans or X-rays of the whole urinary tract are taken - an intravenous program. The urine may also be examined under a microscope for malignant cells. When the diagnosis has been made and the extent of the cancer is known, the type of treatment will be considered.
How is bladder cancer treated?
Treatment will differ according to the spread of the cancer. There are two main groups.
Superficial cancer (non-invasive)
This means there is no evidence that the tumor has spread into the muscle coat of the bladder. The majority fall into this category and can usually be cured. Treatment is usually by cautery (burning of abnormal tissue) through a cytoscope or scraping the tissue away with a specially adapted telescopic instrument. There may be only one, or possibly several, tumors on the bladder. It is known that they can recur and the doctor will advise the patient to have regular checkup examinations by cytoscopy.
Anti-cancer drugs such as mitomycin C, or BCG (Bacillus Calmette-Guerin) are often used by installation into the bladder if it is confirmed that there is an increased risk of new cancers. If neglected, superficial cancer can progress to deep or invasive cancer.
Deep cancer (muscle invasive)
The cancer has grown deeper to involve the muscle lining of the bladder. This is more serious as there is a greater risk that the cancer may spread to the lymph nodes or other organs such as the liver or bone. Further tests like a CT scan or MRI scans will help to confirm that the cancer is confined to the bladder. Treatment is usually a choice between radiation treatment or the total surgical removal of the bladder.
If the bladder has to be surgically removed, urine from the kidneys is diverted to the skin surface just below the waist line using a small portion of the small bowel (known an ileal loop diversion). In this procedure, the tubes from the kidneys are joined to one end of a 12cm length of small bowel and the other end is brought out through the abdominal wall and onto the skin to form a stoma. A special adhesive bag is placed over the stoma to collect the urine. There is a tap on the bag to drain off the urine when necessary.
In certain circumstances, a more sophisticated form of diversion can be constructed. Bowel can be made into a pouch with a tunnel to the skin surface through which the patient passes a small tube to drain the urine. Occasionally, a functioning bladder can be constructed from segments of bowel to form a continent bladder substitute, known as an orthotopic bladder substitute.
If the cancer has spread to the lymph nodes or other organs, treatment with medicines (chemotherapy) may be offered.
Survival Rates
If discovered early and before it has spread to other organs the survival rate is as high as 94%. If it has spread to other nearby organs the survival rate drops to about 49%.
The challenge presents in finding it early enough–it can be easily missed due to vague symptoms. Having a regular urinalysis–or having your urine dipped to check for microscopic amounts of blood–should be done annually by your primary physician. Also, it has been shown that those who develop frequent urinary tract infections develop bladder cancer more frequently, so if you have a higher rate of infection than others, make sure to get checked out every year.
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