Similarities and differences in clinical and pathologic features of inflammatory bowel disease-associated colorectal cancer in China and Canada

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 clinicalpathologic similarities and differences in the IBD-associ吐ed 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%us.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 CDassociated and had less mucinous features,otherwise they were similar in many common features.