Scientists make smoking and bowel cancer link

A firm link between smoking and bowel cancer has been established following a review of studies into the area.

Smoking has long been known to be a contributory factor to the development of many cancers, but until now a direct link between the habit and bowel cancer had yet to be established.

However, research undertaken by Edoardo Botteri and associates at the European Institute of Oncology in Milan suggests smoking accounts for an 18 per cent increase in bowel cancer risk.

Scientists analysed 40,000 bowel cancer cases detailed in 106 previous studies, and found that in addition to a link between smoking and bowel cancer there is also a relationship between deaths from the disease and smoking.

Smokers were discovered to be 25 per cent more likely to die from bowel cancer than people who had never smoked.

The increased risk of both bowel cancer and dying from the disease for smokers was also found to be dependent on the number of cigarettes smoked per day and the length of time a person had been smoking.

Writing in the journal JAMA, the study’s authors say they are hopeful their findings will help to reduce the incidence of bowel cancer.

"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, which currently causes more than 500,000 annual deaths worldwide," they comment.

Despite repeated heath warnings, there are still around 1.3 billion smokers in the world today.

Ed Yong, Cancer Research UK’s health information manager, said: "The list of cancers caused by smoking – already very long – has just become a bit longer, according to this analysis of a huge body of evidence. While smoking only increases the risk of bowel cancer to a small extent, this type of cancer is so common that helping people to quit smoking could help to prevent many cases."

(Source: JAMA: Cancer Research UK: December 2008)