From the Guidelines
For patients with a tubular adenoma found on colonoscopy, the recommended follow-up interval is typically 7-10 years, depending on specific characteristics of the adenoma, as suggested by the most recent guidelines 1. When considering the follow-up interval for a patient with a tubular adenoma, several factors must be taken into account, including the size and number of adenomas, as well as the presence of high-grade dysplasia.
- For patients with 1-2 tubular adenomas less than 10 mm, a follow-up colonoscopy in 7-10 years is generally recommended 1.
- The follow-up interval is based on the understanding that tubular adenomas have malignant potential but generally grow slowly, and that they have the lowest risk of progression to cancer compared to tubulovillous or villous adenomas, but still require surveillance.
- Patients with a single small tubular adenoma with low-grade dysplasia may be suitable for a 7-10 year follow-up interval, as the risk of progression to cancer is relatively low 1.
- However, if the tubular adenoma is large (10 mm or greater), shows high-grade dysplasia, or if multiple adenomas are present (three or more), a shorter interval of 3 years is recommended, as the risk of progression to cancer is higher in these cases 1.
- It is essential to note that these recommendations are based on the assumption that the examination is complete to the cecum with adequate bowel preparation, and that the patient does not have a hereditary CRC syndrome, personal history of inflammatory bowel disease, or other high-risk conditions.
- Patients should be informed that adherence to follow-up recommendations is crucial for early detection and prevention of colorectal cancer, as adenomas represent precancerous lesions that can be removed before they progress to malignancy.
From the Research
Follow-up Colonoscopy for Tubular Adenoma
- The timing of a follow-up colonoscopy for a patient with a tubular adenoma diagnosed on colonoscopy depends on various factors, including the size and histology of the adenoma, as well as the patient's age and location of the adenoma 2, 3, 4.
- Studies have shown that the risk of high-grade dysplasia or invasive carcinoma in colorectal adenomas increases with size, villous histology, left-sided location, and age > 60 years 2, 4.
- For tubular adenomas with minor villous changes, molecular features characteristic of tubulovillous adenomas may be present, suggesting increased malignant potential 3.
- The presence of high-grade dysplasia or villous component in colorectal adenomas < 1 cm can define an advanced adenoma, which may require more intense postpolypectomy surveillance 5.
- However, the interobserver reliability in determining the villous component and high-grade dysplasia in colorectal adenomas < 1 cm may be poor, which can impact the credibility of consensus guidelines for endoscopic surveillance 5.
Risk Factors for High-Grade Dysplasia
- Size is an important risk factor for high-grade dysplasia, with larger adenomas having a higher risk 2, 4.
- Multiplicity of adenomas, tubulovillous/villous histology, location in the rectum, and age are also independent risk factors for high-grade dysplasia 4.
- The prevalence of high-grade dysplasia in adenomas with a size of 0.6-1.0 cm is around 4.1%, and in the 40- to 69-year age group, it is around 3.7% 4.
Implications for Clinical Practice
- The clinical significance of polyps of size < 0.5 cm is controversial, but studies suggest that all adenomas, including those with diameter < 0.5 cm, should be removed whenever possible 2.
- Patients with tubular adenomas should undergo follow-up colonoscopy based on the size and histology of the adenoma, as well as the patient's age and location of the adenoma 2, 3, 4.
- The development of consensus criteria among gastrointestinal pathologists may help improve the interobserver reliability in determining the villous component and high-grade dysplasia in colorectal adenomas < 1 cm 5.