What is bladder cancer?
Bladder cancer is the uncontrolled growth of abnormal cells in the bladder leading to the formation of a tumour. Over time, the tumour may penetrate the bladder lining and invade the surrounding muscle layers. Symptoms include the appearance of blood in the urine and more frequent and painful urination.
Tumours caught at an early stage can be treated with surgery or chemotherapy. Advanced cases of bladder cancer may require the removal of the bladder, with an external drainage bag or internal reservoir to aid in urination.
How does smoking increase the risk of bladder cancer?
Some of the chemicals contained in tobacco smoke cause, initiate or promote cancer. These chemicals cause genetic changes in cells of the bladder which can lead to the development of bladder cancer.
These chemicals or their metabolites are passed along the urinary tract and are stored in the bladder prior to urination. Over time, they may damage the lining of the bladder, leading to cancer.
Current cigarette smokers have a higher risk of bladder cancer than previously reported, according to new research. The study also found that the proportion of bladder cancer due to smoking in women is now the same as for men—about 50%.
In 2011, nearly 70,000 people nationwide are expected to be diagnosed with bladder cancer, and almost 15,000 will die from the disease. Smoking tobacco is the most important known risk factor for bladder cancer.
Previous studies found that 20% to 30% of bladder cancer cases in women were caused by smoking. However, most of the earlier studies were conducted at times or in areas where smoking was much less common among women. The composition of cigarettes has also changed in the past few decades. While there have been reductions in tar and nicotine, the concentrations of other cancer-causing compounds have increased.
The researchers estimated that smoking is responsible for about half of female bladder cancer cases—similar to the proportion found in men in previous studies. The increase in the proportion of smoking-attributable bladder cancer cases among women is likely explained by the greater prevalence of smoking among women.
Former smokers were twice as likely to develop bladder cancer as those who never smoked, and current smokers were 4 times more likely. As with many other smoking-related cancers, smoking cessation was associated with reduced bladder cancer risk.
Nih.org
