Colorectal cancer is the third most common form of cancer and the fourth most frequent cause of cancer deaths worldwide.

The link between cigarette smoking and colorectal cancer has been inconsistent among prior studies. In a new analysis published in the December 17, 2008 issue of the Journal of the American Medical Association, researchers reported that cigarette smoking is significantly associated with both occurrence and death from colorectal cancer .

Researchers from the European Institute of Oncology in Milan, Italy and their colleagues reviewed data from over 100 observational studies and found that smoking was associated with an increase of nearly 11 cases of colorectal cancer per 100,000 person-years. They also found that increasing number of cigarettes smoked per day or number of packs smoked per year was associated with increased risk, but the association was only statistically significant after 30 years of smoking. In terms of risk of death from colorectal cancer, smoking was associated with an increase of approximately 6 deaths per 100,000 person-years.

The researchers suggest that smoking history is an important factor to consider when determining the appropriate age for colorectal cancer screening.

Source

JAMA. 2008;300:2765-2778.