Risk of bladder cancer from smoking higher than previously thought
Smokers may face a higher risk of bladder cancer than previously thought, a US study has revealed.
Women who smoke are also just as likely as male smokers to develop the disease, according to research published in the Journal of the American Medical Association.
More than 350,000 people are diagnosed with bladder cancer every year worldwide, with more than 10,000 of these in the UK. Smoking is the main preventable risk factor for the disease.
Previous studies have indicated that people who are currently smokers are three times more likely to develop bladder cancer than those who have never smoked.
But the latest findings, based on analysis of data from nearly 500,000 people, suggest that current smokers are four times more likely to develop bladder cancer than those who have never smoked.
One reason could be changes in the chemicals used in cigarettes. The researchers said: "The composition of cigarettes has changed during the past 50 years, leading to a reduction in tar and nicotine concentrations in cigarette smoke, but also to an apparent increase in the concentration of specific carcinogens, including beta-naphthylamine, a known bladder carcinogen."
The team, led by Dr Neal Freedman from the National Cancer Institute at the US Department of Health and Human Services, used the results of a lifestyle survey carried out between October 1995 and December 2006.
According to the researchers, the link between tobacco smoking and bladder cancer may also have been strengthened by increased awareness of the risk among smokers, causing more cases to be diagnosed earlier.
Professor David Phillips, a Cancer Research UK expert on carcinogens, said: "We already know that smoking is the single biggest preventable cause of cancer, killing thousands of people prematurely every year. It causes many different types of cancer, including bladder cancer. This very large US study backs up other recent work to show that the risk of bladder cancer from smoking in the Western world is actually increasing.
"The study does not tell us why. It could be due to earlier diagnosis because of increased symptom awareness, but there's also a strong possibility that it's because manufacturers have changed how tobacco is processed in cigarettes. Either way, the risk of bladder cancer from smoking is higher than previously thought. The study also shows that stopping smoking reduces the risk. All the more reason for smokers to quit the habit."
Copyright Press Association 2011