Tobacco smoking is widely acknowledged as the single greatest contributor to bladder cancer. The risk of bladder cancer brought on by smoking, called “excess risk” is four times higher than that of a nonsmoker. Former smokers have twice the excess risk of developing bladder cancer as never-smokers, the study says. Previous studies found the excess risk was three times higher in smokers.
“As with many other smoking-related cancers, smoking cessation was associated with reduced bladder cancer risk. Participants who had been smoke-free for at least 10 years had a lower incidence of bladder cancer compared to those who quit for shorter periods of time or who still smoked,” the study said.
The new study’s author, Dr. Neal Freedman with NCI’s Division of Cancer Epidemiology and Genetics (DCEG) said in a prepared statement that the stronger association between smoking and bladder cancer is possibly due to changes in cigarette composition.