Endoscopic Submucosal Dissection of Deeply Invasive Colorectal Cancers Using the Pocket-Creation Method: Analysis of...

Area of Science:

• Gastroenterology
• Surgical Oncology
• Endoscopic Surgery

Background:

• Standard treatment for T1b colorectal cancer is surgical resection, but endoscopic resection is gaining consideration due to an aging population with comorbidities.
• The pocket-creation method (PCM) for endoscopic submucosal dissection (ESD) is effective for various colorectal tumor morphologies.
• Positive vertical margins can occur even with PCM, necessitating investigation into failure causes.

Purpose of the Study:

• To retrospectively investigate the causes of positive vertical margins in T1b colorectal cancer resections using the pocket-creation method (PCM).
• To evaluate the efficacy of PCM-assisted ESD for achieving complete resection of T1b colorectal cancers.

Main Methods:

• Retrospective analysis of 65 T1b colorectal cancers resected using PCM.
• Classification of cases into positive vertical margin (VM+) and negative vertical margin (VM-) groups.
• Review of ESD specimens and procedure videos for VM+ cases to identify contributing factors.

Main Results:

• 15% of T1b colorectal cancers had positive vertical margins (VM+ group).
• Submucosal fibrosis and slower dissection speed were significantly associated with positive margins.
• Endoscopic technical factors and inherent pathological factors contributed to positive margins in VM+ cases.
• Additional surgery in 6 VM+ patients revealed no residual tumor or lymph node metastases.

Conclusions:

• The pocket-creation method (PCM) facilitates a high rate of negative vertical margins in T1b colorectal cancer resections.
• PCM-assisted ESD achieves complete resection of T1b colorectal cancers, as confirmed by surgical specimens.
• ESD using the PCM is a suitable endoscopic treatment option for T1b colorectal cancers.