From the Guidelines
Sessile serrated adenomas (SSAs) have a significant risk of becoming cancerous, with a similar future colorectal cancer risk as advanced adenomas (AAs), and thus require careful surveillance and management. The risk of SSAs progressing to colorectal cancer is substantial, with approximately 15-30% of SSAs potentially developing into cancer if left untreated, compared to a lower risk of about 5% for tubular adenomas 1. SSAs typically follow a different pathway to cancer, known as the serrated pathway, which is distinct from the conventional adenoma-carcinoma pathway of tubular adenomas.
Some key points to consider in the management of SSAs include:
- The size and characteristics of the SSA, with larger lesions (≥10 mm) and those with dysplasia having a higher risk of future neoplasia or colorectal cancer 1
- The importance of complete removal of these lesions, as incomplete resection significantly increases cancer risk 1
- The need for more aggressive surveillance, with follow-up colonoscopy recommended at 3 years after removal, compared to 5-10 years for low-risk tubular adenomas 1
- The potential for additive or even more than additive risk when SSAs and adenomatous polyps are found together, with an OR for future risk with synchronous AAs and serrated lesions at index exam of 16.04 (95% CI 6.95 to 37) compared with an OR of 3.86 (95% CI 2.77 to 5.39) for AAs alone 1
Overall, the management of SSAs requires a careful and individualized approach, taking into account the size, characteristics, and location of the lesion, as well as the patient's overall risk profile and medical history. Given the significant risk of SSAs becoming cancerous, it is essential to prioritize their detection, complete removal, and surveillance to prevent the development of colorectal cancer.
From the Research
Sessile Serrated Adenomas and Cancer Risk
- Sessile serrated adenomas (SSAs) have been identified as the main precursor lesions in serrated carcinogenesis, accounting for up to one-third of all sporadic colorectal cancers 2, 3.
- The serrated neoplastic pathway, which includes SSAs, is a significant contributor to the burden of colorectal cancers, with up to 30% of all CRC arising from this pathway 3.
- SSAs have a higher risk of incomplete resection and are associated with synchronous and metachronous advanced neoplasia, making them a significant concern for colorectal cancer development 3.
Comparison to Tubular Adenomas
- Studies have shown that SSAs have a similar malignant potential to conventional adenomas, with a higher incidence of high-grade dysplasia or carcinoma compared to hyperplastic polyps 4, 5.
- A study comparing the follow-up of patients with SSAs to those with tubular adenomas found that SSAs were more likely to have recurrent lesions and a higher risk of advanced neoplasia 4.
- The colonoscopic features of SSAs are distinct from those of other serrated lesions and conventional adenomas, making accurate detection and removal crucial for preventing colorectal cancer 5.
Management and Surveillance
- Guidelines recommend managing SSAs as advanced adenomas, with rigorous follow-up and surveillance to prevent colorectal cancer development 4, 6.
- Endoscopists must be aware of the unique features of SSAs to optimize detection, removal, and surveillance of these lesions 6.
- Further research is needed to understand the epidemiology, natural history, and molecular aspects of SSAs to improve management and prevention of colorectal cancer 6.