Adenomas And Cancer Risk


Have you ever heard of adenomas? These growths may not be on your radar, but they could pose a serious risk to your health. An adenoma is a type of tumour that is not cancerous. It originates from the epithelial tissue, which is responsible for covering organs and glands. Adenomas develop gradually and have a resemblance to tiny mushrooms with a stem.

Adenomas can occur in different parts of the body and, while some are harmless, others can increase your risk of developing cancer. With early detection and proper treatment, the risk of cancer can be significantly reduced. 

In this article, we'll take a closer look at adenomas and how they can affect your health. We'll also explore the connection between adenomas and cancer risk, and provide you with important information on how these growths are detected and treated. Whether you're concerned about your own health or that of a loved one, read on to learn more about this hidden threat and how to stay one step ahead of it.

Types of adenomas

Adenomas can have different shapes as they grow. Some look like fingers or leaves on the surface (villous), while others have tube-like structures (tubular). Some have a mix of both (tubulovillous). When a tumour has mostly finger-like or leaf-like projections, it's called a villous adenoma. When it's mostly made up of tube-like structures and has few projections, it's called a tubular adenoma. Tubular adenomas are the most common type of tumour found in the colon, making up more than 80% of cases.1

Tubular adenomas

Tubular adenomas are growths that can occur in the colon, and they can be detected during colonoscopies. They are not cancerous yet but can eventually lead to colon cancer. So they act as an early warning sign. Although many people can develop these growths, only a small percentage of them actually become cancerous.

As people get older and if they are male, they are more likely to have colon cancer. Certain things like having a family member with colon cancer, smoking, drinking too much alcohol, having diabetes, and being overweight can also increase the risk. In the past, research has shown that colon cancer is more common in Black people than in White people, but recent studies have had different results. Colon cancer is less common in developing countries, but it's becoming more common worldwide because of people eating more processed foods and not exercising enough.1

Villous adenomas

Villous features mean that the tumour has finger-like or leaf-like projections on its surface. Villous adenomas are more likely to develop into cancer compared to other types of tumours. Villous adenomas make up a small portion (5% to 15%) of all adenomas. As people get older, their chances of developing colon polyps increase. Studies have shown that by the time people turn 50, around 25% to 30% of them have colon polyps. This number goes up to 50% by the time they reach 70, especially in high-risk countries like the United States. 

However, colon polyps are not very common in younger people. Only about one to four percent of 20 to 30-year-olds have them.2

A villous adenoma is a type of growth that can form in the colon and increase the risk of colorectal cancer. Some things that increase the risk of developing villous adenomas include what you eat and how you live. Eating lots of vegetables and fruit can help protect against adenomas, while consuming a lot of fat and alcohol can increase the risk. Smoking tobacco is also closely linked to the development of adenomas. People with acromegaly, a health condition that causes too much growth hormone, are at a higher risk for developing adenomas and colon cancer. Studies have suggested a link between a specific type of bacteria called Streptococcus bovis and the development of rectal villous adenomas. People who have had a urinary diversion procedure are also at a higher risk. Finally, people with inflammatory bowel disease are also at a higher risk for adenomas and colorectal cancer.2

Tubulovillous adenomas

A tubulovillous adenoma (TVA) is a growth that can occur in the colon and rectum. It's not cancerous but can turn into a type of colon cancer called "adenocarcinoma" if not treated. This type of polyp can form anywhere in the colon and rectum and develops from the cells that line the inside of these tissues. It's important to get TVAs removed to reduce the risk of developing colon cancer over time.

Sessile serrated adenomas/polyps (SSA/P)

Sessile serrated adenoma/polyps (SSA/Ps) are growths in the colon that can lead to colorectal cancer if left untreated. They are difficult to detect and are often not completely removed, which can contribute to "interval cancers." SSA/Ps are different from other types of polyps because they are larger than 5mm, have a thin layer called the "mucus cap," and are usually located in the upper part of the colon. 

They can be identified using magnifying endoscopy, which shows dark spots inside the crypts and varicose microvascular vessels. SSA/Ps have endoscopic characteristics like semi-pedunculated morphologies, double elevations, central depressions, and reddishness. If colonoscopists can identify these characteristics, they can improve the effectiveness of colonoscopy and reduce the risk of interval cancers. It's important to detect and remove SSA/Ps as they can rapidly become dysplastic or invasive carcinomas, which can spread to other parts of the body.

Traditional serrated adenomas (TSA)

Traditional serrated adenomas (TSAs) are a type of polyp that can form in the colon. They are not as common as other types of polyps, accounting for only about 5% of all serrated polyps, but their frequency may increase as screening programs improve and awareness among doctors grows. As a result, it is likely that more TSAs will be detected in the future. It's important to detect and remove TSAs as they can potentially turn into cancer over time. Therefore, it's crucial to be aware of this type of polyp and to monitor them during colonoscopies.3

Factors that increase the risk of adenomas

The exact cause of adenomas is often unknown, but certain factors can increase your risk of developing them. 


People in their 30s or 40s are more likely to develop pituitary adenomas, which are growths that form in the pituitary gland.

Family history

Most adenomas are not passed down from parents, but there are some types that can be caused by genetic factors and run in families. For instance, Familial isolated pituitary adenoma(FIPA). Pituitary adenoma is a noncancerous tumour that grows in the pituitary gland, which is a small gland located at the base of the brain. The pituitary gland produces hormones that are essential for various functions in the body, such as growth, metabolism, and reproduction. Some people may inherit a condition that causes them to develop pituitary adenomas, which can affect the normal functioning of the gland and cause hormonal imbalances.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is a chronic inflammatory condition that affects the digestive tract. Studies have shown that individuals with IBD are at an increased risk of developing adenomas, which are benign tumours that can turn cancerous over time.

Genetic syndromes

Changes in genes can lead to genetic conditions, such as multiple endocrine neoplasia type 1 (MEN1), that increase the chances of developing adenomas. These types of gene mutations are passed down from your biological parents. Some adenoma causes, like familial adenomatous polyposis (FAP), also run in families due to genetic factors.

Symptoms and diagnosis of adenomas


Sometimes, an adenoma may not cause any symptoms, especially if it is small. However, symptoms of adenomas can vary depending on where they are in the body. If an adenoma is larger, it may cause symptoms such as abdominal pain, feeling tired, headaches, anaemia, muscle weakness, feeling sick to your stomach, vomiting, or bleeding from your rectum.

Screening and diagnosis

To diagnose an adenoma, your doctor will first ask about your medical history and examine you physically. They may also request imaging tests like Computerised Tomography (CT) scan, Magnetic Resonance Imaging (MRI), or Positron Emission Tomography (PET) scans to help make a diagnosis. To be sure of the diagnosis, your doctor may also perform a biopsy, which involves taking a small piece of tissue from the adenoma and sending it to a laboratory for analysis. Based on the results, your doctor can confirm whether or not you have an adenoma.

Colonoscopy and polypectomy

A colonoscopy is a medical procedure that lets doctors examine the inside of your colon by using a long, flexible tube that goes in through your bottom. This lets them check for any problems or abnormal growths, like polyps. If they find any, they can take small samples for testing or remove them during the procedure. Polyps are growths in the colon lining that can turn into cancer over time, so it's important to remove them early.

A polypectomy is a medical procedure to remove a growth called a polyp that can be found inside your body. These growths can be cancerous or not, and sometimes it's hard for doctors to tell until they take it out. Some polyps are not cancerous now, but they could become cancerous later on. So, it's important to remove them early to prevent any potential problems down the road.

Adenomas and cancer risk

Explanation of cancer risk

Adenomas are growths that can be found in the colon, and they have the potential to turn into cancer over time. The risk of an adenoma becoming cancerous depends on its size, type, and how long it has been present in the colon. If adenomas are found during a colonoscopy, they are usually removed during the procedure to prevent them from developing into cancer. People who have had adenomas removed should have regular colonoscopies to check for any new growths and reduce the risk of colon cancer.

Relationship between adenomas and colorectal cancer

Most cases of colorectal cancer are caused by the growth and transformation of abnormal tissues in the colon or rectum, known as colorectal dysplasia and adenoma. There are different ways that colorectal cancer can develop, including the serrated pathway and the classical adenoma-carcinoma sequence.

Adenomas and cancer risk in different age groups

A study showed that the prevalence of adenomas detected by colonoscopy is higher among older individuals, men, and black individuals. The prevalence values found are higher than previously suggested for colonoscopy quality standards, suggesting that patient demographic differences in the expected prevalence of adenomas should be incorporated into colonoscopy performance quality measures. Differences in adenoma distribution by sex, age, and race/ethnicity suggest that the effectiveness of different screening strategies may vary by patient demographics.4

Adenoma size and cancer risk

There is an association between the adenoma size and cancer risk. For instance, most colon cancers start as small growths called polyps. However, only a small percentage of these polyps will turn into cancer. The size of the polyp matters because the larger it gets, the more likely it is to become cancerous. If a polyp is bigger than 10mm, or 1cm, the risk of it becoming cancer increases significantly. Studies have shown that larger polyps tend to grow more quickly than smaller ones.

Polyp location and cancer risk

Polyps are a common condition of the large intestine and rectum. They can appear anywhere in the large intestine or rectum. The most cancerous are often found in the left section of the large intestine, known as the sigmoid colon, or the rectum.

Prevention and treatment

Prevention of adenomas

While some risk factors for adenomas are beyond our control, there are steps we can take to improve our chances of staying healthy. Regular health screenings are crucial in detecting adenomas early, especially if you have a higher risk of developing them. Consult your healthcare provider to determine how often you should receive screenings. 

In addition, you can improve your overall health and reduce your risk of adenomas by making some lifestyle changes. These include quitting smoking, eating a healthy diet that includes plenty of fruits, vegetables, and whole grains, exercising regularly, and limiting alcohol consumption. These simple steps can help keep you healthy and reduce your risk of adenomas and other health problems.

Treatment of adenomas

If you have a small adenoma that isn't causing any health problems, your doctor may recommend a "wait-and-see" approach. This means that you won't receive any treatment right away, but instead, your doctor will monitor the adenoma periodically to ensure that it hasn't grown or changed. This approach can be reassuring for those who are concerned about undergoing unnecessary procedures or treatments. 

However, if the adenoma is causing hormonal imbalances, your doctor may prescribe medication to help manage the symptoms. In some cases, these medications can be enough to control the adenoma and prevent it from growing. If the adenoma is large or causing significant health problems, your doctor may recommend surgery to remove it. While surgery can be daunting, it can also be very effective in reducing the risk of the adenoma progressing to cancer and alleviating any symptoms that the growth may be causing. 

Ultimately, the course of action that you and your doctor choose will depend on a variety of factors, including the size and location of the adenoma, as well as any symptoms that you may be experiencing. Whatever your situation, it's important to work closely with your doctor to determine the best course of action for your individual needs.

Surveillance guidelines for adenomas

Surveillance guidelines for adenomas depend on the type of adenoma and your individual risk factors. If you have a small adenoma that isn't causing any health problems, your doctor may recommend periodic monitoring to make sure it's not changing. Depending on where the adenoma is located, your doctor may recommend a colonoscopy or MRI scan for follow-up appointments. 

If you have a higher risk of developing adenomas, your doctor may suggest more frequent monitoring or genetic testing. It's important to attend all scheduled appointments and follow your doctor's recommendations for surveillance. Early detection is crucial in preventing adenomas from developing into cancer, and regular monitoring can help catch any changes early and treat them appropriately.


Adenomas are precancerous growths that develop in the colon and rectum, and their relationship with cancer risk. There are different types of adenomas, such as tubular, villous, and serrated adenomas, and the various factors that increase the risk of developing adenomas, including age, family history, and inflammatory bowel disease.

 Adenomas are usually asymptomatic and differ on where they are located in the body and there are different ways to diagnose adenomas, emphasising the importance of early detection and screening.  Based on the information presented in the article, it is recommended that if you are at risk of developing adenomas, you should consult with your healthcare provider for screening and surveillance guidelines. Regular screening and surveillance are crucial for early detection and removal of adenomas, which can significantly reduce the risk of developing colorectal cancer. It is also essential for individuals with a family history of colorectal cancer or genetic syndromes associated with an increased risk of adenomas to consider genetic counselling and testing to assess their risk and develop an appropriate screening plan.


  1. Taherian M, Lotfollahzadeh S, Daneshpajouhnejad P, Arora K. Tubular adenoma. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Jun 9]. Available from:
  2. Myers DJ, Arora K. Villous adenoma. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Jun 9]. Available from:
  3. Chetty R. Traditional serrated adenoma (Tsa): morphological questions, queries and quandaries. Journal of Clinical Pathology [Internet]. 2016 Jan 1 [cited 2023 Jun 9];69(1):6–11. Available from:
  4. Corley DA, Jensen CD, Marks AR, Zhao WK, de Boer J, Levin TR, et al. Variation of adenoma prevalence by age, sex, race, and colon location in a large population: implications for screening and quality programs. Clin Gastroenterol Hepatol [Internet]. 2013 Feb [cited 2023 Jun 9];11(2):172–80. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Aamal Alshihawi

Bachelor of Science in Public Health, Asian University for Women, Bangladesh

Aamal is a public health practitioner with experience in research and management roles in the NGO sector. She has two years of experience in health promotion, mental health, and research. Also, she works in the education sector and has over two years of experience in curriculum content development and design. She is working now as an internship coordinator.

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