Similarities and Differences in Clinical and Pathologic Features of Inflammatory Bowel Disease-Associated Colorectal Cancer in China and Canada
Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD), has become a global health concern. One of the most severe complications of IBD is the development of colorectal cancer (CRC), known as IBD-associated CRC (IBD-CRC). This study aimed to compare the clinical and pathologic features of IBD-CRC in patients from China and Canada, focusing on the similarities and differences between the two populations.
Background and Significance
IBD-CRC is a significant cause of morbidity and mortality in patients with long-standing IBD. The risk of CRC in IBD patients is influenced by factors such as disease duration, extent of colitis, severity of inflammation, and the presence of concurrent primary sclerosing cholangitis (PSC). While the incidence of IBD-CRC has been well-documented in Western countries, there is limited data on its characteristics in Asian populations, particularly in China. This study provides a comparative analysis of IBD-CRC in patients from Beijing, China, and Calgary, Canada, to better understand the disease’s clinical and pathologic features in different geographic and ethnic contexts.
Methods
The study retrospectively analyzed data from 78 patients with IBD-CRC, including 25 from Beijing and 53 from Calgary, over a 13-year period. The Beijing group consisted of 22 UC-associated and 3 CD-associated CRC cases, while the Calgary group included 32 UC-associated and 21 CD-associated CRC cases. The data were collected from two tertiary medical centers: Peking Union Medical College Hospital in Beijing and Calgary Laboratory Services in Canada. The study compared demographic characteristics, disease duration, extent of colitis, histologic features of CRC, tumor-node-metastasis (TNM) staging, and the presence of PSC. Surveillance colonoscopy practices and the detection of precancerous lesions were also evaluated.
Results
Common Features of IBD-CRC in Both Groups
Both the Beijing and Calgary groups shared several common features of IBD-CRC. These included a male predominance (64.1% overall), long disease duration (median of 13 years), and a high proportion of multifocal lesions (11.5%). The majority of cancers were located in the left side of the colon and rectum (64.4%), and most tumors were moderately or poorly differentiated adenocarcinomas (71.2%). Chronic active colitis was present in the background mucosa in 76.9% of cases, and the TNM staging distribution was similar, with 23.1% in Stage I and 26.9% in Stage IIa.
Differences Between the Beijing and Calgary Groups
Despite these similarities, several notable differences were observed between the two groups. The Beijing group had a significantly higher percentage of UC-associated CRC (88.0% vs. 60.4%, P = 0.018) and a younger mean age at CRC diagnosis (48.6 ± 12.8 years vs. 61.6 ± 14.7 years, P < 0.001). Additionally, the Beijing group had a lower prevalence of mucinous adenocarcinoma (7.1% vs. 42.4%, P = 0.001) and no cases of concurrent PSC, compared to 5.7% in the Calgary group. The distribution of TNM stages also differed, with more cases in Stage IIb in the Beijing group (32.0% vs. 0, P < 0.001).
Surveillance Colonoscopy and Precancerous Lesions
Surveillance colonoscopy, defined as regular colonoscopies with biopsies every 1 to 2 years, was performed in 24.4% of the combined groups. The detection rate of precancerous lesions was significantly higher in the surveillance group (41.4% vs. 17.0%, P = 0.002). However, there was no significant difference in TNM staging, tumor location, or the prevalence of mucinous or signet-ring cell features between the surveillance and non-surveillance groups.
Discussion
CD-Associated CRC in Asia
The Beijing group had a significantly lower proportion of CD-associated CRC compared to the Calgary group. This difference is likely due to the lower incidence and prevalence of CD in China. Previous studies in Japan have also reported a lower incidence of CD-associated CRC, consistent with the findings in this study. The lower prevalence of CD in China may explain the rarity of CD-associated CRC in the Beijing group.
Surveillance Colonoscopy and Cancer Prevention
Surveillance colonoscopy is a critical tool for detecting precancerous lesions and early-stage CRC in IBD patients. This study found that surveillance colonoscopy was associated with a higher detection rate of precancerous lesions, supporting its role in reducing the risk of IBD-CRC. However, the low adherence to surveillance colonoscopy in both groups highlights the need for improved patient education and healthcare practices to enhance the effectiveness of surveillance programs.
Histologic and Prognostic Features of IBD-CRC
The histologic features of IBD-CRC, including mucinous adenocarcinoma and signet-ring cell carcinoma, are associated with a worse prognosis. The Beijing group had a lower prevalence of mucinous adenocarcinoma compared to the Calgary group, which may reflect differences in disease biology or genetic factors. The younger age at CRC diagnosis in the Beijing group suggests that IBD-CRC may develop earlier in Chinese patients, emphasizing the need for early and effective surveillance strategies.
Limitations of the Study
This study has several limitations. The data on past medical treatment and smoking status were incomplete, preventing a detailed analysis of their impact on IBD-CRC development. Additionally, the study was based on surgically resected cases, which may introduce selection bias. Further research is needed to explore the role of these factors in the carcinogenesis of IBD-CRC.
Conclusion
This comparative study of IBD-CRC in patients from Beijing, China, and Calgary, Canada, revealed both similarities and differences in clinical and pathologic features. While both groups shared common characteristics such as long disease duration, multifocal lesions, and advanced TNM staging, the Beijing group had a higher proportion of UC-associated CRC, younger age at diagnosis, and lower prevalence of mucinous adenocarcinoma. These findings highlight the importance of considering geographic and ethnic differences in the management and surveillance of IBD-CRC. Improved adherence to surveillance colonoscopy and further research into the underlying factors contributing to these differences are essential for reducing the burden of IBD-CRC in different populations.
doi.org/10.1097/CM9.0000000000000525
Was this helpful?
0 / 0