Smoking and risk of colon polyps

Cigarette smoking appears to promote the development of polyps in the colon, especially those that are more likely to progress to cancer. Italian researchers analysed 42 earlier studies and found that smokers were twice as likely as non-smokers to develop colon polyps. Former smokers also showed a heightened risk, though it was less than that of current smokers. The analysis also found that smoking was particularly linked to high-risk polyps; while most colon polyps are not dangerous, high-risk ones are relatively more likely to become cancerous. The findings offer strong evidence that cigarette smoking contributes to both the formation of polyps and their aggressiveness. While smoking does appear to be a risk factor for polyps, past studies have been mixed as to whether it raises the risk of colon cancer itself. This paradox may be explained by the design of the studies. For example, many studies may not have followed smokers for a long enough period; any heightened colon cancer risk from smoking could take decades to emerge. The current findings suggest that people who refrain from smoking can lower their risk of polyps and, potentially, colon cancer. They also raise the possibility that smokers would benefit from earlier colon cancer screening. Colon polyps typically emerge after age 50, and the large majority of colon cancers develop after this age as well. It is still not clear whether smokers tend to develop polyps at an earlier-than-average age, or whether their polyps tend to progress more rapidly to cancer. But what is clear is that both current and former smokers should be especially vigilant about following the current recommendations on colon cancer screening.