Prognosis and clinical features of ulcerative colitis-associated colorectal cancer in Japan: Results of a nationwide registry over 20 years

Abstract

15117 Background: Clinicopathological features of ulcerative colitis (UC)-associated colorectal cancer are not fully clarified due to the small number of the cases compared with sporadic colorectal cancer, especially in the Asian population. This study aims to clarify the prognosis and the clinicopathological features of UC-associated colorectal cancer in the Japanese population compared with sporadic colorectal cancer. Methods: All patients diagnosed as UC before treatment of colorectal cancer or pathologically diagnosed as such in the surgical specimens from 1978 to 1998 were extracted from a large nationwide database of colorectal cancers, Multi-Institutional Registry of Large-Bowel Cancer in Japan. Clinicopathological features and cancer-specific survival were compared between UC-associated colorectal cancer and sporadic colorectal cancer. Results: Among 108,536 cases of colorectal cancers registered between 1978 and 1998, a total of 169 cases of UC- associated colorectal cancers were identified including 121 cases undergoing surgery. Proportion of UC-associated colorectal cancer has increased in the second half of 1990. UC-associated colorectal cancer had younger age, more multiple lesions, higher prevalence of superficial or invasive morphological types, and higher frequency of mucinous or signet ring cell carcinomas compared with sporadic cancer. Overall survival of UC-associated colorectal cancer was significantly poorer than that of sporadic cancer among Dukes’ C cases (p<0.05). Conclusions: UC-associated colorectal cancer has different biological features from sporadic cancer including poor prognosis at the advanced stage. In the light of finding that UC-associated colorectal cancer has increased over ages, the importance of surveillance program should be reminded for early detection of cancer. No significant financial relationships to disclose.