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  • Understanding Adenoma in Colon: Symptoms, Risks, and Treatment Options

Adenoma in colon, precursors to colorectal cancer, exist as a wake-up call for many individuals. Understanding their formation, progression, and the risk factors involved is a crucial first step in preventing this common health concern.

Key Takeaways

  • Adenoma formation and progression can lead to cancer development, and should be monitored closely.

  • Early detection through regular screenings is critical for preventing malignant transformation of adenomas into carcinomas.

  • Regular colorectal cancer screenings, a balanced diet, physical activity & avoidance of risk factors are key to reducing the risk of adenoma formation & improving prognosis.

Adenoma Formation and Progression

Illustration of different types of adenomas in the colon

Adenomas, also known as colorectal polyps or adenomatous polyps, are growths that line the colon’s interior and possess the potential to develop into cancer. They’re primarily classified into neoplastic and non-neoplastic polyps, with the former presenting an elevated risk of cancer development. Hyperplastic polyps, on the other hand, are a type of non-neoplastic polyps. Cancer serrated polyps are another type of colon polyps that may also have malignant potential. These precancerous polyps, including adenomatous and serrated polyps, should be monitored closely to prevent the progression to cancer.

Approximately 5% of adenomas have the potential to turn malignant, making early detection and removal paramount.

Types of Adenomas

Adenomas can exhibit either nonneoplastic or neoplastic traits, with neoplastic adenomas carrying a higher propensity for malignant progression. Among these, tubular adenoma is the most common type, with smaller sizes compared to villous adenomas. The unique characteristics of tubular adenomas include nuclear hyperchromatism, nuclear crowding, and a reduction in the number of goblet cells, among others.

Malignant Transformation

The adenoma-carcinoma sequence explains how adenomas transform into carcinomas, highlighting the importance of early detection. Adenocarcinoma is the predominant type of colorectal cancer, which can develop from various types of adenomas. The size of an adenoma and its degree of dysplasia greatly influence its potential for malignancy.

The importance of regular screenings cannot be overstated, as these can aid in detecting and eliminating adenomas before they turn cancerous.

Risk Factors for Adenoma Development

Certain factors significantly increase the risk of adenoma development, such as advancing age, family history, and lifestyle factors like smoking, excessive alcohol consumption, and obesity.

Age and Family History

Adenomas typically start to develop around the age of 50-60 years, with the risk significantly increasing with age. Regular screenings are advised to commence from age 45, especially for individuals with a family history of adenomas.

Having a family history of adenomas dramatically heightens the risk, necessitating more frequent screenings.

Lifestyle and Diet

Lifestyle choices, including a history of smoking, excessive alcohol consumption, and obesity, can exacerbate the risk of adenoma development. Dietary habits, such as low fruit intake and high-fat consumption, can also contribute to this risk.

Conversely, engaging in regular physical activity can substantially reduce this risk.

Identifying Symptoms of Colon Adenomas

While most adenomas are asymptomatic, some may present with symptoms such as changes in bowel habits, rectal bleeding, and abdominal pain. The frequency of these symptoms can vary, with some individuals remaining asymptomatic.

Asymptomatic Adenomas

Asymptomatic adenomas are usually identified through screening tests like colonoscopies or imaging tests. Most adenomas do not cause symptoms and are typically discovered during routine colonoscopies. About 25 to 30 percent of colon adenomas are asymptomatic.

Detecting and eliminating these adenomas early can hinder their progression to cancer, subsequently lessening the risk of colorectal cancer and enhancing patient outcomes.

Symptomatic Adenomas

Symptomatic adenomas may manifest symptoms like rectal bleeding, abdominal pain, or changes in bowel habits. Rectal bleeding from adenomas is distinct due to their precancerous nature and may signal their potential to progress into colorectal cancer.

Persistent changes in bowel habits, particularly when coupled with symptoms such as rectal bleeding, could suggest the presence of adenomas or inflammatory bowel disease.

Screening and Diagnosis of Colon Adenomas

Photo of a colonoscopy procedure

Consistent screenings for adenomas are key to stopping their progression to cancer, and colonoscopies are advised every 10 years for those aged 50 and above. The frequency of these screenings, however, can vary based on factors such as family history of adenomas and the initial polyp size and microscopic features.


Colonoscopies are considered the gold standard for detecting and removing adenomas, with a sensitivity ranging from approximately 68% to 84%, and a specificity ranging from 79% to 85%. A colonoscope is used to thoroughly examine the entire colon for any irregularities, which typically lasts between 30 to 60 minutes.

Leading up to the procedure, patients must follow a few steps:

  1. Follow a light, low-fiber diet for several days.

  2. Limit intake to clear liquids the day prior to the procedure.

  3. Perform a bowel cleanse using a prescribed laxative formula.

These steps are necessary to ensure a successful procedure.

Alternative Screening Methods

Alternative screening methods, such as fecal occult blood testing and sigmoidoscopy, can also be used to detect adenomas. Fecal occult blood testing involves analyzing a small stool sample to detect concealed traces of blood.

Sigmoidoscopy, on the other hand, enables the visualization of the rectum and sigmoid colon to identify early changes or lesions in these areas.

Treatment and Management of Colon Adenomas

Illustration of polyp removal during a colonoscopy

The treatment options for adenomas and serrated polyp depend on their size and type and may include simple polypectomy, endoscopic mucosal resection, or snare polypectomy.

For larger or more complex colorectal adenomas, surgical removal may be necessary, utilizing methods such as partial colectomy, intraoperative transanal resection, and laparoscopy or laparotomy, among others.

Polyp Removal

Most adenomas can be removed during a colonoscopy, using a procedure known as polypectomy, which involves using a wire loop passed through the colonoscope to sever the polyp from the colon using an electric current. This procedure can remove a range of adenoma polyps, such as tubular adenomas, villous adenomas, and tubulovillous adenomas. Polyp removal during a colonoscopy can prevent colorectal cancer, reduce cancer-related deaths, enable early detection and treatment, and is minimally invasive. However, potential complications include bleeding and perforation.

Surgical Approaches

In the case of larger adenomas or those with a higher risk of malignancy, surgical interventions may be necessary. These include polypectomy, local excision, and endoscopic mucosal resection.

For individuals with familial adenomatous polyposis, the primary surgical methods include:

  • Total colectomy plus ileorectal anastomosis

  • Total proctocolectomy with ileostomy

  • Restorative proctocolectomy with or without mucosectomy and ileal-pouch anastomosis.

Prevention Strategies for Adenoma Formation

Photo of a person maintaining a healthy lifestyle

Strategies to prevent adenoma formation encompass:

  • Frequent screenings, advised every 10 years for average-risk individuals aged 50 and above

  • Lifestyle adjustments like adhering to a nutritious diet

  • Engaging in regular physical activity

  • Avoiding known risk factors like smoking and heavy alcohol consumption.

Regular Screenings

Consistent colorectal cancer screening for detecting adenomas through colonoscopy presents several benefits, including cancer prevention, early detection, an increased rate of adenoma detection, and enhanced survival rates.

Individuals should commence these screenings from age 50, especially for those with a family history of adenomas.

Lifestyle Modifications

A diet rich in low-fat dairy, fruits, vegetables, unprocessed grains, and folate can prevent the formation of adenomas, while a high intake of red meat and processed meat is associated with an elevated risk. Regular physical activity can lower the risk of adenoma development, while obesity and weight gain can heighten this risk.

Smoking and alcohol consumption are also associated with an elevated risk of adenoma formation.

Complications and Prognosis

While complications from colonoscopy are rare, they can include perforation of the colon, post-polypectomy syndrome, and bleeding.

However, the long-term outlook for individuals with adenomas is generally positive, especially with regular screenings and early detection.

Colonoscopy Complications

Illustration of potential complications from colonoscopy

Complications following a colonoscopy can include:

  • Respiratory depression

  • Perforation of the colon (0.016% to 0.5%)

  • Bleeding (typically linked to polypectomy)

  • Postpolypectomy syndrome

  • Reactions to sedatives

While these complications are typically rare, they can be serious. Perforation of the colon has an average rate of 0.03% to 0.8% and bleeding may occur immediately following the colonoscopy.

Post-polypectomy syndrome is a rare complication that arises after a colonoscopy with polypectomy involving electrocautery.

Long-term Outlook

Detecting colon adenomas early has a significant effect on the prognosis, resulting in more positive outcomes. The size and type of adenoma can also significantly influence the long-term prognosis, with larger adenomas associated with a higher risk of developing colon cancer, especially in individuals with a family history of colon issues.

The probability of adenoma recurrence is between 10-50% within a span of 5-10 years, underlining the need for ongoing care to sustain a positive long-term prognosis.


Understanding adenomas, their formation, progression, and the risk factors involved is crucial for preventing colorectal cancer. With regular screenings, early detection, and lifestyle modifications, adenomas can be detected and removed before they progress to cancer, leading to a favorable prognosis.

Frequently Asked Questions

What is an adenoma within the colon considered?

Colonic adenomas, also known as tubular adenomas, are polyps found in the colon that have the potential to develop into cancer. Found during colonoscopies, these precancerous polyps serve as an early warning system for colorectal cancer and can transform into malignant structures.

How long does it take for a colon adenoma to become cancer?

It typically takes between 10 and 15 years for an adenomatous polyp to become cancerous. Most colon cancer screenings are scheduled every 10 years to allow time for the removal of any polyps before they turn malignant.

How do you treat adenomas in the colon?

Excision and complete removal of adenomatous tissue during colonoscopy is considered the treatment of choice for adenomas in the colon, as it reduces the risk of colorectal cancer. In some cases surgery, consultations, dietary changes and regular monitoring may be necessary.

What is the difference between a colon adenoma and a polyp?

An adenoma (adenomatous polyp) is a type of polyp made up of tissue that looks similar to the normal inner lining of the colon or rectum, but is different under a microscope. Polyps, on the other hand, are generally defined as abnormal growths protruding into the lumen of the colon.

Is an adenoma polyp bad?

Adenoma polyps have a high risk of turning cancerous and therefore should not be taken lightly. They are more difficult to remove due to their sessile nature and can become cancerous given enough time to grow.

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