Clinical features of ulcerative colitis-associated colorectal cancer in Japan: an analysis of 169 cases over 20 years

Abstract

13544 Background: Development of colorectal cancer is a well-known long-term complication of ulcerative colitis (UC). However, specific clinical features of UC-associated colorectal cancer have been controversial mainly due to the small number of cases, especially in the Asian countries. This study aims to clarify the clinicopathological features of UC-associated colorectal cancer compared with non-UC-associated colorectal cancer in Japan, using a large nationwide database. Methods: All patients pathologically diagnosed as colorectal cancer from 1978 to 1998 were extracted from the nationwide database, “Multi-Institutional Registry of Large-Bowel Cancer in Japan”, which covers almost 10% of all colorectal cancers in Japan. Clinicopathological factors were compared between those associated with UC and the others. Survival analysis in each TNM stage was performed using the Kaplan-Meier method. Results: Among 108,536 cases of colorectal tumors registered from 1978 to 1998, a total of 169 cases of UC-associated colorectal cancers were identified. All cases were from the Asian population. UC-associated cases showed higher prevalence of females, younger age, higher incidence of multiple cancers, and higher incidence of mucinous adenocarcinomas. On the other hand, there were no differences in tumor sites, family history of colorectal cancer, lymph node metastasis, distant metastasis, TNM stage, and CEA level adjusted by TNM stage between the two groups. Survival analysis revealed poorer prognosis in UC-associated colorectal cancers at TNM stage 3. Conclusions: UC-associated colorectal cancer showed unique histological features compared with usual colorectal cancer. The survival of UC-associated colorectal cancer with lymph node metastasis was poorer than usual colorectal cancer, and therefore, intensive adjuvant therapy and close follow-up is needed after surgery in this patient group. No significant financial relationships to disclose.