P234 Differentiation of histopathological features between sporadic and colitis-associated colorectal cancer in a nationwide large cohort.

Uchino, M.(1)*;Ikeuchi, H.(2);Noiguchi, T.(3);Okabayashi, K.(4);Futami, K.(5);Tanaka, S.(6);Ohge, H.(7);Watanabe, K.(8);Itabashi, M.(9);Okamoto, K.(10);Okita, Y.(11);Mzushima, T.(12);Mizuuchi, Y.(13);Yamada, K.(14);Shimada, Y.(15);Sato, Y.(16);Kimura, H.(17);Takahashi, K.(18);Hida, K.(19);Kinugasa, Y.(20);Okuda, J.(21);Daito, K.(22);Koyama, F.(23);Ueno, H.(24);Yamamoto, T.(25);Hanai, T.(26);Kobayashi, H.(27);Kono, T.(28);Ajioka, Y.(29);Sugihara, K.(30);Ishihara, S.(3);

(1)Hyogo College of Medicine, Department of Inflammatory Bowel Disease, Nishinomiya, Japan;(2)Hyogo medical University, gastroenterological surgery, Nishinomiya, Japan;(3)The University of Tokyo, Surgical Oncology, Tokyo, Japan;(4)Keio University School of Medicine, Surgery, Tokyo, Japan;(5)Fukuoka University Chikushi Hospital, Surgery, Fukuoka, Japan;(6)Hiroshima University Hospital, Endoscopy, Hiroshima, Japan;(7)Hiroshima University Hospital, Infectious Diseases, Hiroshima, Japan;(8)Tohoku University Graduate School of Medicine, Surgery, Sendai, Japan;(9)Tokyo Women's Medical University, Surgery, Tokyo, Japan;(10)Tokyo Yamate Medical Center, Coloproctology, Tokyo, Japan;(11)Mie University Graduate School of Medicine, Gastrointestinal and Pediatric Surgery- Institute of Life Sciences, Tsu, Japan;(12)Osaka University, Gastroenterological Surgery, Osaka, Japan;(13)Kyushu University, Surgery and Oncology, Fukuoka, Japan;(14)Coloproctology Center Takano Hospital, Surgery, Kumamoto, Japan;(15)Graduate School of Medical and Dental Sciences- Niigata University, Digestive and General Surgery, Niigata, Japan;(16)Toho University Sakura Medical Center, Surgery, Chiba, Japan;(17)Yokohama City University Medical Center, Inflammatory Bowel Disease Center, Yokohama, Japan;(18)Tohoku Rosai Hospital, Colorectal Surgery, Sendai, Japan;(19)Kyoto University Hospital, Surgery, Kyoto, Japan;(20)Tokyo Medical and Dental University, Gastrointestinal Surgery, Tokyo, Japan;(21)Osaka Medical and Pharmaceutical University, General and Gastroenterological Surgery, Osaka, Japan;(22)Kindai University- Faculty of Medicine, Surgery, Osaka, Japan;(23)Nara Medical University, Surgery, Nara, Japan;(24)National Defense Medical College, Surgery, Tokorozawa, Japan;(25)Yokkaichi Hazu Medical Center, Inflammatory Bowel Disease Center, Yokkaichi, Japan;(26)Fujita Health University- School of Medicine, Surgery, Toyoake, Japan;(27)Teikyo University Mizonokuchi Hospital, Surgery, Kanagawa, Japan;(28)Sapporo Higashi Tokushukai Hospital, Advanced Surgery Center, Sapporo, Japan;(29)Graduate School of Medical and Dental Sciences- Niigata University, Molecular and Diagnostic Pathology, Niigata, Japan;(30)Tokyo Medical and Dental University, Surgery, Tokyo, Japan; Study Group for Inflammatory Bowel Disease Associated Intestinal Cancers by the Japanese Society for Cancer of the Colon and Rectum


Background: Colitis-associated colorectal cancer (CAC) can develop in patients with inflammatory bowel disease, and histological features differ between CAC and sporadic colorectal cancer (CRC). Moreover, advanced CAC has a poorer prognosis than sporadic CRC. Therefore, we compared histopathological findings distinct from cancer stage between CAC and sporadic CRC to evaluate the features of CAC.


Methods: We reviewed the clinical and histopathological data collected from 43 institutions, including surgery and gastroenterology departments, in the Japanese Society for Cancer of the Colon and Rectum between 1983 and 2020. Patient characteristics were compared between ulcerative colitis (UC), Crohn’s disease (CD), and sporadic CRC. Comparisons were performed by using all collected data or propensity score-matched data.


Results: A total of 1,077 patients with UC-CAC, 297 with CD-CAC, and 136,927 with sporadic CRC were included in all collected data. Although the prevalence of well or moderately differentiated adenocarcinoma (G1:well differentiated and G2:moderately differentiated) decreased according to tumor progression in all diseases (p<0.01, figure1), the prevalence of G3,G4, including signet ring cell carcinoma, mucinous carcinoma, poorly differentiated adenocarcinoma, neuroendocrine carcinoma and squamous cell carcinoma, was significantly higher in CAC than in sporadic CRC. Based on propensity score-matched data for 982 patients with UC and 268 with CD, the prevalence of histopathological findings other than G1 and G2 was also significantly higher in CAC (figure2,3). At pT4, mucinous carcinoma occurred at a significantly higher rate in patients with CD (45/86 (52.3%)) than in those with sporadic CRC (13/88 (14.8%)) (p<0.01).


Conclusion: Malignant potential is higher in CAC than in sporadic CRC according to tumor progression, which may lead to the poor prognosis of CAC.