Cigarette smoking is associated with the occurrence of colorectal cancer and with mortality from the disease, according to a multinational team.

“Because smoking can potentially be controlled by individual and population-related measures, detecting a link between colorectal cancer and smoking could help reduce the burden of the world’s third most common tumour,” Edoardo Botteri, at the European Institute of Oncology in Milan, and associates write in this week’s Journal of the American Medical Association.

The investigators identified 106 studies looking at smoking and colorectal cancer that included almost 40,000 cases. Pooling the data showed an 18 per cent higher relative risk of developing colorectal cancer for smokers compared with non-smokers.

The relative risk of dying from the disease was 25 per cent higher for smokers, which Dr Botteri’s group suggests may indicate a more aggressive tumour type associated with smoking.

“We believe that smoking represents an important factor to consider when deciding on the age at which colorectal cancer screening should begin, either by lowering the age in smokers or increasing the age in non-smokers,” the researchers suggest.

Source: Journal of the American Medical Association, December 17, 2008.