LAUSR

Abstract Background: Colorectal cancer (CRC) has become one of the major life-threatening complications in patients with inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD). This study aimed to explore the clinical-pathologic similarities and differences in the IBD-associated CRC (IBD-CRC) between patients in China and Canada. Methods: Data of 78 patients with IBD-CRC retrospectively retrieved from two representative medical institutions in Beijing (China) and Calgary (Canada) over the same past 13 years, including 25 (22 UC-associated and three CD-associated) from Beijing group and 53 (32 UC-associated and 21 CD-associated) from Calgary group, were compared with regards to their clinical and pathologic characteristics. Results: Several known features of IBD-CRC were seen in both groups, including long duration and large extent of colitis, active inflammation background, multifocal lesions, and advanced tumor-node-metastasis stage. Beijing group showed a significantly higher percentage of UC (88.0% vs. 60.4%, P = 0.018), younger age at diagnosis of CRC (48.6 ± 12.8 years vs. 61.6 ± 14.7 years, P < 0.001), lower ratio of mucinous adenocarcinoma (7.1% vs. 42.4%, P = 0.001) compared with Calgary group. None of the Beijing group had concurrent primary sclerosing cholangitis, while 5.7% of Calgary group did. Surveillance colonoscopy favored the detection rate of precancerous lesions (41.4% vs.17.0%, P = 0.002). Conclusions: As compared with patients from the Calgary group, the IBD-CRC patients in Beijing group were younger, less CD-associated and had less mucinous features, otherwise they were similar in many common features.