Current sessile serrated lesion incidence: implications for future clinical practice

Background: Sessile serrated lesions (SSL) account for up to 30% of colorectal carcinoma pathogenesis. With multiple classification changes and improvements in colonoscopy equipment and technique, historical reporting may have underestimated the true incidence of SSLs. This study aimed to determine the incidence of SSLs in patients undergoing colonoscopic investigation in Canterbury, New Zealand over a 1-year period and describe their clinical and pathological characteristics. Methods: Electronic records were searched to identify all lower endoscopy procedures with polypectomy performed from 1 January 2022 to 1 December 2022 (inclusive). Patients' electronic records were used to collect histological classification, location and size of each polyp removed during their procedure. The primary outcome was the number of procedures that had one or more SSL, adenoma or hyperplastic polyp identified. Secondary outcomes included histological classification, location and size of each polyp removed. Results: There were 4346 procedures completed during the study period. Of these, 64.1% (2786) had a polypectomy and 18.6% (808) had at least one SSL excised. Individual polyp analysis was completed on 9166 polyps and found that 24.0% of polyps removed were SSLs and they were found predominately in the right colon (65.1% right colon, 32.6% left colon, 2.3% rectum). SSLs were typically <10 mm (84.8%). Conclusion: This study found a higher incidence of SSLs compared to previous research. These results raise questions regarding whether SLL rates have been historically underestimated, whether SSL detection rate should be included as a key performance indicator and raises further concerns regarding the use of computed tomography colonography as a screening tool.