P276 Prevalence, clinicopathological, and biological characteristics of serrated polyps in patients with ulcerative colitis

Nishio, M.(1);Kunisaki, R.(1);Shibata, W.(1);Ajioka, Y.(2);Hirasawa, K.(3);Takase, A.(4);Chiba, S.(4);Inayama, Y.(4);Ueda, W.(5);Okawa, K.(5);Tsunoda, S.(1);Azuma, D.(1);Yaguchi, K.(1);Fujii, K.(1);Nakamori, Y.(1);Madarame, A.(1);Nishida, D.(1);Fuse, M.(1);Araki, K.(1);Saigusa, Y.(6);Kimura, H.(1);Kato, J.(7);Maeda, S.(8);

(1)Yokohama City University Medical Centre, Inflammatory Bowel Disease Centre, Yokohama, Japan;(2)Niigata University Graduate School of Medical and Dental Sciences, Division of Molecular and Diagnostic Pathology, Niigata, Japan;(3)Yokohama City University Medical Centre, Division of Endoscopy, Yokohama, Japan;(4)Yokohama City University Medical Centre, Division of Pathological Diagnosis, Yokohama, Japan;(5)Osaka City Juso Hospital, Department of Gastroenterology and Hepatology, Osaka, Japan;(6)Yokohama City University Graduate School of Medicine, Department of Biostatistics, Yokohama, Japan;(7)Chiba University Graduate School of Medicine, Department of Gastroenterology, Chiba, Japan;(8)Yokohama City University Graduate School of Medicine, Department of Gastroenterology, Yokohama, Japan;

Background

Serrated polyps are recognized as precursors of colorectal cancer in general population and have recently been reported in patients with ulcerative colitis (UC). However, their prevalence and detailed characteristics remain unclear.

Methods

The prevalence and clinicopathological and biological characteristics of serrated polyps in patients with UC were retrospectively examined in a single tertiary inflammatory bowel disease centre in Japan from 2000 to 2020.

Results

In total, 252 neoplasms, including 36 serrated polyps (26 in colitis-affected segments, 10 in colitis-unaffected segments), were identified in 187 patients with UC. The proportion of serrated polyps was significantly higher from 2010 to 2020 (35/213, 17%) than from 2000 to 2009 (1/39, 3%; p = 0.023). Serrated polyps in colitis-affected segments were common in patients with extensive colitis (88%), a history of persistent active colitis (58%), and a long duration of UC (12.1 years). Serrated polyps in colitis-affected segments were more common in men (88%). Of 26 serrated polyps in colitis-affected segments, 15, 6, and 5 were categorized as sessile serrated lesion (SSL)-like dysplasia, traditional serrated adenoma (TSA)-like dysplasia, and serrated dysplasia not otherwise specified (SD NOS), respectively. SSL-like dysplasia was common in the proximal colon (67%) and with BRAF mutation (62%), whereas TSA-like dysplasia and SD NOS were common in the distal colon (100% and 80%) and with KRAS mutations (100% and 75%). CpG island hypermethylation phenotype-positive status was observed in 60% cases of TSA-like dysplasia but in only 25% cases of SSL-like dysplasia and SD NOS.

Conclusion

Serrated polyps have recently been increasing in patients with UC. Serrated polyps in colitis-affected segments were common in men with extensive and longstanding colitis, suggesting that chronic inflammation is involved in the development of serrated polyps in patients with UC.