[Clinicopathological differences in laterally spreading tumors between rectum and colon]

Area of Science:

• Gastroenterology
• Oncology
• Pathology

Background:

• Laterally spreading tumors (LSTs) are a distinct subtype of colorectal neoplasia.
• Understanding clinicopathological differences between rectal and colonic LSTs is crucial for appropriate management.

Purpose of the Study:

• To investigate and compare the clinicopathological characteristics of LSTs originating from the rectum and colon.
• To identify differences in tumor types, size, grade, and malignant potential between rectal and colonic LSTs.

Main Methods:

• Retrospective analysis of 198 colorectal LST cases (116 rectal, 82 colonic) diagnosed between 2012 and 2017.
• Evaluation of clinicopathological data including endoscopic classification, tumor size, and degree of neoplasia.

Main Results:

• LST-GM was predominant in the rectum (71.7%), while LST-FE was predominant in the colon (78.0%) (P<0.01).
• Rectal LSTs were significantly larger (52.03 mm vs 25.37 mm, P<0.01) and showed a higher frequency of high-grade intraepithelial neoplasia (31.0% vs 18.3%, P<0.05).
• Malignant potential, indicated by high-grade intraepithelial neoplasia + invasive carcinoma, was higher in rectal LSTs (41.8% vs 22.2%, P<0.05).

Conclusions:

• Rectal and colonic LSTs display significant clinicopathological variations.
• LST-GM is more common in the rectum, whereas LST-FE is more prevalent in the colon.
• Rectal LSTs, particularly LST-GM, possess a higher malignant potential compared to colonic LSTs.