Objective The longitudinal risk of colorectal cancer (CRC) associated with subtypes of serrated polyps (SPs) remains incompletely understood.
Design This community-based, case–control study included 317 178 Kaiser Permanente Northern California members who underwent their first colonoscopy during 2006–2016. Nested within this population, we identified 695 cases of CRC and 3475 CRC-free controls (matched 5:1 to cases for age, sex and year of colonoscopy). Two expert pathologists reviewed the tissue slides of all SPs identified on the first colonoscopy and reclassified them to sessile serrated lesions (SSLs), hyperplastic polyps (HPs) and traditional serrated adenomas. SPs with borderline characteristics of SSLs but insufficient to make a definitive diagnosis were categorised as unspecified SPs. The association with development of CRC was assessed using multivariable logistic regression.
Results Compared with individuals with no polyp, the adjusted ORs (aORs) for SSL alone or with synchronous adenoma were 2.9 (95% CI: 1.8 to 4.8) and 4.4 (95% CI: 2.7 to 7.2), respectively. The aORs for SSL with dysplasia, large proximal SSL,and small proximal SSL were 10.3 (95% CI: 2.1 to 50.3), 12.8 (95% CI: 3.5 to 46.9) and 1.9 (95% CI: 0.8 to 4.7), respectively. Proximal unspecified SP also conferred an increased risk (aOR: 5.8, 95% CI: 2.2 to 15.2). Women with SSL were associated with higher risk (aOR: 4.4; 95% CI: 2.3 to 8.2) than men (aOR: 1.7; 95% CI: 0.8 to 3.8).
Conclusion Increased risk of CRC was observed in individuals with SSLs, particularly large proximal ones or with dysplasia, supporting close endoscopic surveillance. Proximal unspecified SPs were also associated with increased risk of CRC and should be managed as SSLs.
- colorectal cancer
- SERRATED POLYPS
- cancer prevention
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information. Additional information relevant to this study is available upon request.
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Contributors DL obtained funding, designed and directed the project, led data interpretation and led manuscript development. ARD and MR reviewed pathology slides. LL extracted data and performed the statistical analysis. NYL participated in review of medical records for data validation. LBA coordinated the project, arranged acquisition of pathology slides and assisted in manuscript preparation. JKL, DAC and TRL participated in study design and data interpretation. LJH assisted with study design, data interpretation and manuscript development. All authors critically reviewed and approved the manuscript.
Funding Kaiser Permanente Northern California Division of Research, the Permanente Medical Group Delivery Science and Applied Research Program and the Physician Researcher Program.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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To editorial staff: please remove TSA from the abbreviation list here sine it is not shown in Table 3.