Smoking Increases Colorectal Cancer Risk

We often talk about ‘smokers’ lungs’, and while it hardly has the same ring to it, the rarely mentioned, so-called ‘smoker’s colon’ is another example of how detrimental smoking is to our health.

You might be wondering how a primarily respiratory-related vice could possibly cause problems in your gut. After all, your lungs and large intestines belong to very different body systems.

As unlikely as it sounds, multiple studies have shown not only the correlation between smoking and the occurrence of colorectal cancer, but have also found evidence of the carcinogenic components of cigarettes leading to colorectal cancer.

Exposure to cigarette smoke, be it through firsthand or secondhand smoking, introduces carcinogenic toxins into the body. But how does it get from your respiratory system to your digestive tract? Besides inhaling cigarette smoke or sometimes swallowing its components, much of the carcinogenic compounds found in cigarettes reach the large intestine and other parts of the body via the bloodstream when these compounds are absorbed in the lungs.

Many of these harmful chemicals may ring a bell; polycyclic aromatic hydrocarbons (PAHs), nitrosamines, organic hydrocarbons and aldehydes are amongst the classes of chemicals found in cigarettes and in alcohol, red and processed meats — other known causes of colorectal cancer.

Even chemicals that are not originally carcinogenic can become cancer-causing after being broken down in the body. These broken-down chemicals, or metabolites, often exert harm on cellular components such as DNA, proteins and membranes, increasing the risk of cancerous cell formation when the damaged DNA is repaired.

Besides the direct harm caused by these carcinogens, a separate study on mice has also shown that the gut bacteria population of mice that are exposed to cigarette smoke is different than that of smoke-free mice. The resultant alteration not only affects the presence of carcinogenic metabolites in the large intestine but also impairs the gut’s mucosal barrier.

Besides the direct harm caused by these carcinogens, a separate study on mice has also shown that the gut bacteria population of mice that are exposed to cigarette smoke is different than that of smoke-free mice. The resultant alteration not only affects the presence of carcinogenic metabolites in the large intestine, but also impairs the gut’s mucosal barrier.

Unfortunately, there are no “safe” levels in which moderate smoking does not cause any harm. While those exposed to secondhand smoke are also at risk, the likelihood of developing colorectal cancer remains higher for individuals who do smoke.

Compared to non-smokers, smoking presents a 39% higher risk in males and 20% in females, though the occurrence of colorectal cancer is differently localized between the sexes. Men who smoke are more likely to develop cancer in the descending colon, while colorectal cancer in female smokers are localized in the ascending colon.

As with many other lifestyle choices, stubbing out your cigarettes and permanently quitting will immediately improve your chances and minimize the risk of developing cancer.

However, with all vices, simply quitting is easier said than done. Find sustainable solutions that can help quitting easier for you. Figure out what works for you and cut back slowly. And while you chew on your gum to curb your tobacco addictions, here is something else to chew on — your smoking habits do not affect just your health but also that of others around you.

Exposure to secondhand smoke (i.e. passive smoking) not only increases the odds of getting colorectal cancer but can also lead to earlier development of colorectal cancer in younger individuals. This is despite colorectal cancer being one that typically occurs in older individuals aged above 50.

No matter how long you’ve been smoking, it’s never too late to quit, not just for your own health’s sake but also that of the people important to you.