The clinicopathological features of ulcerative colitis-associated colorectal cancer (UC-CRC) have not yet been fully clarified, especially in Asian populations. This study aimed to clarify the prognosis and clinicopathological features of UC-CRC in comparison with sporadic CRC in the Japanese population.

Histologically diagnosed UC-CRC patients between 1978 to 1998 were extracted from the Multi-Institutional Registry of Large-Bowel Cancer in Japan, a large nationwide CRC database, and the clinicopathological features and postoperative survival rates of UC-CRC patients and sporadic CRC patients were compared.

Among the 108,536 CRC patients registered between 1978 and 1998, a total of 169 UC-CRC patients were identified, including 121 patients who had been treated surgically. The proportion of UC-CRC patients increased in the period between 1995 and 1998 compared to that between 1978 and 1994. Comparisons with the sporadic CRC patients showed that the UC-CRC patients were younger, had a higher proportion of multiple cancer lesions, had higher proportions of superficial type lesions and invasive type lesions morphologically, and had higher proportions of mucinous or signet ring cell carcinomas. In stage III, UC-CRC patients had a poorer survival rate than the sporadic CRC patients (43.3% versus 57.4%, P = 0.0320).

UC-CRC increased over the investigated time periods and showed a poorer survival than sporadic CRC in the advanced stage, while no difference was observed in the early stage. By detecting UC-CRC at an early stage we can expect a similar postoperative outcomes to that of sporadic CRC. These results stress the importance of surveillance for the early detection of UC-CRC. Inflamm Bowel Dis 2011