From the Guidelines
Sessile serrated adenoma (SSA) should be completely removed, typically via endoscopic mucosal resection for larger lesions, and follow-up surveillance colonoscopy is recommended at 3 years for SSAs smaller than 10mm without dysplasia, and at 1 year for SSAs with dysplasia or those larger than 10mm, as stated by the British Society of Gastroenterology position statement on serrated polyps in the colon and rectum 1. The diagnosis of SSA is crucial due to its potential to progress to colorectal cancer through the serrated pathway. Key characteristics of SSA include:
- Flat, often right-sided lesions
- Abnormal crypt architecture
- Potential to progress to colorectal cancer
- Difficulty in detection during colonoscopy due to flat appearance and indistinct borders For the treatment of SSA, the following approaches are recommended:
- Complete removal via endoscopic mucosal resection for larger lesions
- Use of a stiff snare and submucosal lifting for smaller lesions
- Cold snaring for lesions in the proximal colon
- Consideration of operator variability and outcomes in the management of these lesions, with resection of large proximal SSPs optimally dealt with by individuals and centres with expertise 1. It is essential to note that high-quality bowel preparation and careful examination technique are crucial for proper identification and management of SSAs. Additionally, family members of patients with SSAs may benefit from earlier screening colonoscopies due to potential genetic factors. The British Society of Gastroenterology position statement on serrated polyps in the colon and rectum provides guidance on the management of these lesions, including surveillance strategies and special situations such as serrated polyposis syndrome 1.
From the Research
Diagnosis of Sessile Serrated Adenoma (SSA)
- The diagnosis of SSA is challenging due to its similarity to hyperplastic polyps, and it is often susceptible to pathologic misdiagnosis 2.
- Certain endoscopic techniques such as chromoendoscopy, narrow band imaging, water immersion, and wide-angle viewing may improve SSA detection 2.
- The use of updated image-enhanced endoscopy systems, including autofluorescence imaging (AFI) and narrow-band imaging (NBI), may be promising for detecting SSA 3.
- Magnifying chromoendoscopy using both indigocarmine and crystal violet, and NBI with magnification, can be applied for differential diagnosis of SSA and hyperplastic polyps 3.
Treatment of Sessile Serrated Adenoma (SSA)
- Emerging endoscopic techniques such as underwater polypectomy, suction pseudopolyp technique, and piecemeal cold snare polypectomy are helpful tools for removing SSA 2.
- Endoscopic resection techniques, including endoscopic mucosal resection or endoscopic submucosal dissection, are useful for treating SSA with dysplasia or invasive carcinoma 4.
- Surgical resection with lymph node dissection may be indicated when SSA with invasive carcinoma is endoscopically suspected, due to the high risk of lymph node metastasis 4.
- Patients with confirmed SSA should undergo surveillance at intervals similar to what is recommended for patients with conventional adenomas, and may also be able to lower their risk of future polyps by targeting modifiable risk factors 2.
Characteristics of SSA
- SSA are usually larger than 5 mm, frequently covered by a thin layer called the "mucus cap", and are more commonly located in the proximal colon 5.
- Endoscopic characteristics of SSA, including (semi)pedunculated morphology, double elevation, central depression, and reddishness, may help accurately diagnose SSA with advanced histology 4, 5.
- Magnifying narrow-band imaging findings, including dark spots inside the crypts and varicose microvascular vessels, can effectively differentiate SSA from hyperplastic polyps 5.