Overview

Tubular adenomas (TA) are types of polyps, which are small growths that develop from mucosal tissue within the body. They are most commonly found in the colon and rectum.  They can lead to uncomfortable symptoms, and sometimes even more serious conditions such as colorectal cancer. They are identified easily through a common procedure called a colonoscopy, which is where a small camera is inserted into the rectum and used to take photos of the intestines. They can be removed easily, and are not usually a cause for major concern. However, if they are particularly large, reoccur often after removal or contain cancerous cells, they can develop into a more serious health problem.¹

Colorectal cancer is the third most prevalent cancer in the world and is the second most common cause of cancer-related deaths globally.² If left untreated, TA can develop into colorectal cancer as the cancerous cells within the polyp may develop into a tumour and spread throughout the body. Routine screenings for TA alongside research into potential risk factors can help us understand and educate populations on how to reduce prevalence of TA. Resultantly reducing the occurrence of colon cancer.

Risk Factors 

Diet

Diet has a huge impact on both physical and mental well-being. What we choose to put in our bodies from day to day can affect sleep quality, and stress levels and make us more or less susceptible to certain diseases or conditions. Fibre is well known for aiding digestion and promoting the healthy functioning of the gut. One study found that higher dietary fibre intake resulted in lower incidences of colon polyps.³ Eating lots of food high in fibre such as fruits and vegetables and trying to avoid sugary highly processed foods may help reduce risks of TA. Foods high in fats such as red or highly processed meat have been linked to increased risks of colon cancer.⁴ Diet is thought to affect the gut through mechanisms involving inflammatory and immune cells, both of which can influence cancer development and susceptibility. 

Harmful habits  

It is well known that smoking has carcinogenic effects on the body. Studies have shown that smoking has been linked to an increased risk of developing TA.⁵ The strength of this correlation is dependent on factors such as the size and type of adenoma (some carry higher risks than others) and the duration of smoking exposure. The most significant association was found in long-term smokers, with this group carrying the largest adenoma recurrences. 

The same can be said for alcohol consumption, another significant risk factor in the development of TA. The toxic products produced when alcohol is broken down within the body can lead to dysfunctional cell repair and proliferation. This may be an influential factor in why studies have found links between alcohol consumption and the presence of TA.^6-8

Environmental factors

Environmental factors such as climate, culture, economic status and urbanisation can contribute to diet and lifestyle. In urbanised areas, food options are often highly processed and contain a lot of preservatives. This is in order to meet the demands that coincide with high populations and a low proportion of space to grow produce and keep livestock. Food has to be outsourced from destinations across the world, reducing the freshness of produce. This also makes fresh foods more expensive, and therefore less attainable for certain populations. People often opt for quick, cheaper meals which are highly processed and do not provide a balanced diet. Increasing access to and education about healthy diets and their importance may reduce the incidence of TA and colorectal cancer in more urbanised areas.  

Technological advancements have led to society leading more sedentary lifestyles, with days spent sitting behind screens. Obesity is one of the leading causes of death in the world, with the prevalence of obesity on the incline.⁹ Studies have shown significantly more TA present in obese patients than in controls.¹⁰ Providing further evidence that diet can be used to help aid prevention of TA and resultant colon cancer. 

Genetics

Genetic mapping is a method that clinicians can use to try and determine if someone is more at risk of developing cancer as a result of their genetic makeup. This can be useful as individuals who have a family history of cancer will be flagged up and perhaps invited to more frequent and comprehensive cancer monitoring procedures. This can be key in early detection and prevention of potentially life-threatening cancers such as colon cancer. If people have a family history of developing colon polyps or cancers, it could be that they have a genetic disposition which makes them more likely to develop such things in their lives.¹¹

A specific example of a genetic predisposition to colon polyps and colorectal cancer is familial adenomatous polyposis. This is a condition in which thousands of polyps or TA are present within the bowel, significantly increasing the risk of cancer developing. People affected by this disease may have to surgically remove the bowel in order to solve this problem.¹²

Prevention

Diet

Eating a diet rich in plant-based foods, fibre, whole grains and minerals such as calcium has been seen to lower risks of colorectal cancer in populations. Dietary composition contributes to the makeup of the gut microbiome, which is the vast array of bacterial species within your gut. It has been seen that altering diet changes the makeup of your microbiome and influences the gene expression and metabolic pathways that occur within the gut.⁴ It could be that these pathways and genes may influence the likelihood of the development of TA, with certain microbiomes creating environments within the gut more conducive to TA than others. 

There is sufficient evidence and logic to warrant further investigations into how improving diet can help prevent TA development. Improving the quality and amount of research will help set a basis for education and awareness around this topic. Encouraging diets within communities that are rich in fresh produce, antioxidants, gut-loving bacteria and anti-inflammatory food groups may reduce the presence of TA.  

Lifestyle

Living a healthy lifestyle could be a great way to prevent the development of TA and as a result, reduce the risk of developing colorectal cancer. Maintaining a healthy diet, exercising regularly and reducing unhealthy habits such as alcohol and cigarette consumption will seriously reduce the presence of risk factors associated with TA. These habits will also help reduce stress and improve sleep, other very influential factors in the overall health and well-being of individuals. Stress levels can be managed through relaxation and mindfulness, as well as frequent exercise. Less stress can help reduce levels of anxiety and depression, conditions that can be very damaging to sleep quality and overall health. Considering and appreciating the importance of all of these factors can help individuals make choices that may significantly reduce the risk of developing TA. With less stress, better sleep and a healthy diet come anti-inflammatory mechanisms and less exposure to carcinogenic processes within the body.

Emerging therapies

There is growing popularity towards the use of probiotics and prebiotics to regulate and encourage healthy bacteria within the gut microbiome. Probiotics possess anti-inflammatory, anti-cancer and anti-obesity properties. Whereas prebiotics have been found to prevent cancerous cell development.¹³ Incorporating such things into a balanced and healthy diet could further prevent the development of potentially cancerous TA. 

It is important to tailor treatment options depending on genetics, metabolism and exposure to risk factors. Personalised medicine and nutrition could help high-risk people lower their chances of developing TA. As diagnostic techniques improve such as colonoscopies and genetic screening, doctors can help reduce the impact that TA and resultant colon cancer have on society. However, there is a lot of room for more research and clinical trials in order to solidify evidence and make more solid conclusions about the exact mechanisms that come into play regarding diet, lifestyle and TA development. 

Summary

TA are types of polyps most commonly found within the colon. If left undiscovered, these growths can become cancerous over time. A simple outpatient procedure is all that is required for the removal of these mostly harmless tissues. However, early detection through colonoscopies and continual monitoring of high-risk populations creates a significant burden on healthcare organisations. Furthermore, colon cancer contributes to a large proportion of cancer-related deaths. Correlations between lifestyle, dietary habits and TA prevalence have led to an increase in research into potential risk factors and preventative measures. There is significant evidence within the current literature that warrants further investigation into the complex interplay between diet, lifestyle and their influence on the gut. Adequate education on making healthy dietary choices and encouraging frequent exercise within communities is essential.