Endoscopic Submucosal Dissection: A Key Technique in Preventing Colorectal Cancer

When patients notice symptoms of colorectal cancer or receive a positive fecal occult blood test, a colonoscopy is typically performed. During the colonoscopy, larger tumors may be found on the intestinal mucosa. These tumors are often unsuitable for direct endoscopic removal but do not yet require surgical resection of the intestine and surrounding lymph nodes. In such cases, where the tumors are suspected to be benign but cannot be confirmed with 100% certainty, Endoscopic Submucosal Dissection (ESD) can be used for both diagnosis and treatment.

The Procedure of Endoscopic Submucosal Dissection (ESD)

ESD is similar to a colonoscopy for the patient but requires general anesthesia and takes longer to perform. During the procedure, the doctor uses special electrosurgical and cutting tools through the colonoscope to remove a section of tissue from around the tumor, typically 2 to 4 cm in size. This tissue is then sent for pathological examination to determine if it is benign, an in-situ carcinoma, or a malignant tumor.

Diagnostic and Therapeutic Benefits

ESD primarily removes only the mucosa and a small part of the submucosa, which is insufficient for treating malignant tumors. Thus, ESD is usually chosen when the tumor is relatively large but not suspected to be deeply invasive or malignant. One significant advantage of ESD is that it allows for the removal of a larger, continuous section of the mucosa, which can then be thoroughly examined by a pathologist. If only small biopsy samples are taken from a larger lesion, it is impossible to confirm the entire lesion's nature with certainty. ESD provides a more comprehensive diagnostic and therapeutic approach by removing the entire affected area.

If the pathological examination reveals that the tumor is benign or an in-situ carcinoma, no further treatment is needed, and follow-up will be similar to that for benign colorectal polyps. However, if the examination shows a malignant tumor, standard cancer treatments, such as surgical resection of the intestine and surrounding lymph nodes, may be necessary.

Characteristics of Polyps and Cancer Risk

Larger, flatter, and more irregularly surfaced polyps have a higher chance of becoming malignant. ESD is currently an out-of-pocket procedure, but its advantage lies in removing intestinal lesions without major surgery. According to current theories on colorectal cancer development, malignant tumors originate from early mucosal changes (benign polyps) that gradually transform over time. Statistics show that larger, flatter, and more irregularly surfaced polyps are more likely to become malignant. Therefore, removing larger flat polyps with ESD can successfully prevent them from developing into cancer over the years.

Most colorectal cancers develop from polyps, so early removal of detected polyps or larger flat tumors is recommended to prevent further complications.