What is tubular adenoma?

From the Guidelines

Tubular adenoma is a type of benign polyp found in the colon, characterized by its tubular glandular structure, and is classified as such if more than 80% of the polyp contains tubular elements 1.

Definition and Classification

Tubular adenomas are the most common type of adenoma, and their classification is based on the percentage of tubular elements present in the polyp.

• If more than 80% of the polyp contains tubular elements, it is classified as a tubular adenoma.
• If more than 80% of the polyp contains villous elements, it is classified as a villous adenoma.
• If neither tubular nor villous elements exceed 80%, then the polyp is classified as a tubulovillous adenoma.

Risk Factors and Surveillance

The development of tubular adenomas is associated with various risk factors, including age over 50, family history of colorectal polyps or cancer, smoking, excessive alcohol consumption, obesity, and a diet high in red meat and low in fiber 1.

• For a single small (less than 1 cm) tubular adenoma with low-grade dysplasia, a follow-up colonoscopy in 5-10 years is generally recommended, as the risk of developing advanced neoplasia is low 1.
• However, for larger adenomas, multiple adenomas, or those with high-grade dysplasia, more frequent surveillance at 3-5 year intervals may be necessary, as the risk of developing advanced neoplasia is higher 1.

Importance of Screening and Surveillance

Regular screening colonoscopies are essential for early detection and removal of these precancerous lesions, significantly reducing the risk of colorectal cancer.

• The US Multi-Society Task Force on Colorectal Cancer recommends risk stratification of patients based on the findings at the baseline colonoscopy, with surveillance intervals tailored to the individual's risk level 1.

From the Research

Definition of Tubular Adenoma

• A tubular adenoma is a type of polyp found in the colon or rectum, characterized by its tubular shape and adenomatous histology 2.
• It is a precursor lesion to colorectal cancer, and its removal during colonoscopy can help prevent the development of cancer 3, 4, 5.

Characteristics of Tubular Adenoma

• Tubular adenomas are typically small and rarely bear high-grade dysplasia 4.
• They are often found in the rectosigmoid region of the colon 2.
• The risk of advanced metachronous colorectal adenoma is lower in patients with tubular adenomas compared to those with villous or tubulovillous adenomas 4.

Risk of Colorectal Cancer

• The risk of colorectal cancer is higher in patients with adenomas ≥20 mm in diameter or with high-grade dysplasia 3.
• Patients with tubular adenomas have a lower risk of colorectal cancer compared to those with advanced adenomas or serrated polyps 5.
• Regular surveillance examinations can provide sufficient colorectal carcinoma prevention in patients with tubular adenomas 4.

Surveillance and Follow-up

• Patients with tubular adenomas may not require intensive surveillance, and follow-up colonoscopy can be performed at longer intervals 5.
• The risk of new adenomas and significant neoplasia increases with time, and surveillance intervals should be tailored to individual patient risk factors 6.