What is the significance of a 1 cm Sessile Serrated Lesion (SSL) polyp?

From the Guidelines

For a 1 cm sessile serrated lesion (SSL) polyp, I recommend complete endoscopic removal followed by surveillance colonoscopy in 3 years. This recommendation is based on the most recent and highest quality evidence available, which suggests that SSLs ≥10 mm have a potential to progress to colorectal cancer through the serrated neoplasia pathway 1. The British Society of Gastroenterology position statement on serrated polyps in the colon and rectum also recommends a one-off colonoscopic surveillance examination at 3 years for patients with SSLs ≥10 mm or serrated lesions harbouring dysplasia, including traditional serrated adenomas 1.

Key Considerations

• The 1 cm SSL polyp should be completely excised, typically using endoscopic mucosal resection (EMR) technique with submucosal injection to ensure complete removal.
• The specimen should be retrieved and sent for pathological examination to confirm the diagnosis and assess for any high-grade dysplasia.
• After removal, the site should be carefully inspected to ensure complete resection with no residual polyp tissue.
• SSLs are precancerous lesions that often occur in the proximal colon and can be more difficult to detect due to their flat appearance and indistinct borders.
• They typically have a longer transformation time to cancer compared to conventional adenomas but require appropriate surveillance due to their malignant potential.

Surveillance Interval

• The 3-year surveillance interval is appropriate for SSLs ≥10 mm without dysplasia, as these lesions have a potential to progress to colorectal cancer through the serrated neoplasia pathway 1.
• Recent studies have shown that large (≥10 mm) serrated lesions are associated with the same future colorectal cancer risk as advanced adenomas (AAs) 1.
• The risk of finding an advanced adenoma at surveillance when an AA and serrated lesion were found together was fourfold higher than when an AA alone was the index lesion, suggesting that the risk may be more than additive between serrated and adenomatous lesions 1.

From the Research

Significance of a 1 cm Sessile Serrated Lesion (SSL) Polyp

• A 1 cm SSL polyp is considered significant due to its potential to develop into colorectal cancer via the serrated neoplastic pathway 2, 3.
• The clinical features of SSLs, including size (> 5 mm), location in the proximal colon, and presence of a mucus cap, indistinct borders, and a cloud-like surface, are important for diagnosis 2.
• A size of > 5 mm is a significant factor for the diagnosis of SSLs, and polyps greater than 5 mm should be biopsied to determine their histology 2, 3.
• The presence of a 1 cm SSL polyp may indicate a higher risk of cancer, especially if it is located in the proximal colon or has synchronous neoplasms 4, 5.
• Endoscopic removal of SSLs is recommended, and complete removal is crucial to prevent the development of cancer 3, 4.
• Follow-up colonoscopy is recommended to monitor for any new or recurrent SSLs, especially in patients with a history of high-risk SSP 6.

Risk Factors Associated with SSLs

• Female gender is associated with the presence of high-risk SSP at index colonoscopy 6.
• Age ≥75 years and previous high-risk SSP are independently associated with high-risk SSP at follow-up colonoscopy 6.
• Male gender is associated with synchronous adenoma and cancer, as well as synchronous adenoma, SSL, and cancer 5.
• Proximal colon location is associated with SSL and synchronous adenoma and cancer 2, 5.

Diagnosis and Treatment of SSLs

• Endoscopic diagnosis of SSLs can be challenging, but the use of narrow-band imaging or chromoendoscopy may facilitate detection and assessment of extent of lesions 3.
• A diagnostic score system, such as the endoscopic SSL diagnosis score, can be used to predict pathological SSLs with high sensitivity, specificity, and accuracy 2.
• Endoscopic mucosal resection or endoscopic submucosal dissection is useful for removing SSLs with dysplasia or invasive carcinoma 4.
• Surgical resection with lymph node dissection may be indicated for SSLs with invasive carcinoma that are endoscopically suspected 4.