What are the screening methods for colorectal precancerous lesions?

Colorectal cancer (CRC) is one of the most common malignant tumors in the world, and colorectal precancerous lesions are an important stage in its occurrence. Since colorectal precancerous lesions are often asymptomatic and the development process is highly hidden, screening has become an important part of precancerous lesion management. The screening and diagnosis methods for colorectal precancerous lesions are as follows:

1. Colonoscopy

Colonoscopy is the "gold standard" for the diagnosis of colorectal precancerous lesions and colorectal cancer , and is also the most important screening method. Through colonoscopy, doctors can directly observe and locate lesions and obtain tissue samples for pathological evaluation.

However, colonoscopy is an invasive examination and is not suitable for large-scale screening.

2. Fecal testing

Fecal testing is a non-invasive and convenient examination method that does not require bowel preparation and can be performed at home . Fecal multi-target DNA testing is a screening method based on the molecular characteristics of colorectal cancer, which is tested by analyzing gene mutations in stool samples. Compared with fecal occult blood testing, fecal multi-target DNA testing is more accurate.

However, stool testing is less sensitive than colonoscopy for colorectal adenomas and, if the test result is positive, a colonoscopy is still needed for further characterization.

3. Barium enema

Barium enema is not as commonly used as colonoscopy and stool testing for colorectal precancerous lesions. It has lower sensitivity and specificity and cannot determine the extent of colorectal cancer invasion of the bowel wall.

It is usually used only as a backup test when colonoscopy fails or is not possible.

4. CT Simulation of Three-Dimensional Colonography

CT simulated three-dimensional colonography is an imaging examination method that is comparable to colonoscopy in detecting larger adenomas and colorectal cancer. However, the accuracy of this method is low for lesions with a diameter of less than 1 cm. Therefore, the guidelines do not recommend it as a colorectal screening method.

5. Genetic syndrome screening

Certain hereditary syndromes increase the risk of colorectal cancer, such as Lynch syndrome, familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome (PJS), and juvenile polyposis syndrome (JPS). For people with a relevant family history, screening for hereditary syndromes should be performed to detect them as early as possible and take appropriate preventive measures.

In summary, the screening and diagnosis of colorectal precancerous lesions are important links in the prevention and management of colorectal cancer. The risk of colorectal precancerous lesions can be effectively detected and assessed through methods such as colonoscopy, stool testing, barium enema, CT simulation of three-dimensional colonography, and genetic syndrome screening. In order to improve the prevention effect of colorectal cancer, it is recommended to select appropriate screening methods according to individual conditions and conduct regular screening for colorectal precancerous lesions.