How does the serrated polyp pathway alter CRC screening and surveillance?

Area of Science:

• Gastroenterology
• Oncology
• Pathology

Background:

• Colorectal cancer (CRC) screening aims to reduce mortality by detecting early-stage cancers and premalignant polyps.
• Adenomas have traditionally been viewed as the primary screening-relevant precursor lesions for CRC.
• Emerging evidence highlights the serrated pathway as a significant contributor to CRC, particularly interval CRC, and proximal colon cancers.

Purpose of the Study:

• To provide an overview of the serrated polyp pathway in colorectal cancer development.
• To discuss the clinical implications of the serrated pathway, including its impact on CRC screening.
• To highlight the sessile serrated adenoma/polyp (SSA/P) as a key precursor lesion in this pathway.

Main Methods:

• Literature review and synthesis of current research on the serrated pathway.
• Analysis of the molecular characteristics (e.g., BRAF mutations, CIMP-high) associated with serrated lesions.
• Discussion of diagnostic challenges, including nomenclature and pathologist variability.

Main Results:

• The serrated pathway, characterized by BRAF mutations and CIMP-high, is an important contributor to CRC.
• Sessile serrated adenoma/polyps (SSA/P) are the most significant precursor lesions within the serrated pathway.
• Challenges in SSA/P identification and endoscopic detection impact clinical management and CRC surveillance.

Conclusions:

• The serrated pathway, especially SSA/P, plays a critical role in colorectal cancer, including interval cancers.
• Improved understanding and detection of serrated polyps are essential for optimizing CRC screening and prevention.
• Further research is needed to address diagnostic variability and clinical management of serrated lesions.