The Butt Stops Here: the story of tobacco and adenomatous polyps

The past two months have been an exciting time for me as I embark on my fellowship experience. I started out on my endoscopy month scoping routine outpatient cases. During this time, I noticed a trend. Patients that smoked had more polyps in their colon.

This isn’t a new concept. In fact, there is strong evidence that associates cigarette smoking and adenomatous colorectal polyps, which eventually progress to colorectal cancer (CRC). The idea is similar to a lot of other cases; tobacco contains a whole lot of carcinogens that bind DNA and lead to irreversible genetic damage to normal colorectal mucosa.

A meta-analysis of cigarette smoking and adenomatous polyps published in Gastroenterology showed that an individual who smoked 1 pack of cigarettes per day for 50 years or 2 packs per day for 25 years has almost twice the probability of having an adenoma in comparison with an individual who never smoked (link here). The risk of high-risk adenomas was greater than the risk of low-risk adenomas for all 3 smoking classes (current, former, and ever smoker), reaching a statistical significance for current smokers and for ever smokers. High risk and low risk adenomas based on the 42 studies included are defined below.


Low Risk Adenomas High Risk Adenomas
< 10 mm

Only tubular component

No dysplasia

< 3 adenomas

> 10 mm

Villous or tubulovillous component


> 3 adenomas


Does quitting help the situation?

As it turns out, smoking cessation at any point can improve your risk. A 2009 prospective study using 184,187 patients showed that among former smokers, the risk of CRC decreased as time of cessation grew longer and had a positive association with earlier ages of cessation. If you quit before the age of 40 years or have quit more than 31 years ago, there was no association between former smoking and CRC seen at all (Link here). This is actually great news! Targeting smoking cessation can help actually prevent polyp formation and eventual progression to CRC.

Because they are a high risk population, appropriate screening and surveillance can contribute to CRC prevention. You might ask why don’t we screen smokers earlier like we do patients with hereditary polyp syndromes? It’s because the US general and the International Agency for Research on Cancer have only been able to conclude that there is a correlation between the two, not necessarily causation. When they review the studies, they think that the association is actually confounded by factors associated with smoking rather than smoking itself. This includes things like patients not understanding the consequences of smoking, not being able to access their colonoscopy, and not being able to access colonoscopy preparations.

What should we do as physicians?

Despite being a subspecialist, we should preach preventative care and encourage smoking cessation. Of course, this isn’t just focused on gastroenterologist. Every subspeciality has seen the effect of smoking on their particular system. This conversation can happen during an office visit or before the outpatient procedure. I know we are all under a serious time crunch during these clinic visits, but this can be a quick 3-5 minute conversation that is worth having with your patients. I’m not just writing this here to urge you, but to also remind myself to address this issue with my limited patient interaction time, while I wait for my attending.

One way to do a brief intervention is to use the 5 A’s of smoking cessation. Ask about tobacco use, advise about cessation, assess their willingness to quit, assist with information and resources and lastly arrange follow-up with their primary care doctor. Information refers to the association of smoking and colonic polyps with the possible progression to CRC. Remember, finding polyps means more surveillance colonoscopies. Let’s be honest, no one enjoys the process of getting a colonoscopy!

Do you have any tips on leading discussions regarding smoking cessation that have worked for you? Would love to hear your thoughts!



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