| [ Summary ] |
The incidence of colorectal cancer is increasing in patients with longstanding and extensive ulcerative colitis. This cancer is known as ´colitic cancer´ in Japan. However, the term usually seem to be unused in western countries. Eaden et al., using meta-analysis techniques, reported that the decade long incidence rates for colitic cancer correspond to the cumulative probabilities of 1.6 % (95 % confidencial interval : 1.2-2.0) by 10 years, 8.3 % (95 % CI : 4.8-11.7) by 2O years, and 18.4 % (95 % CI : 15.3-21.5) by 30 years. The worldwide cancer incidence rates varied geographically, being 5/1,000 person years duration (pyd) in the USA, 4/1,000 pyd in the UK, and 2/1,000 pyd in Scandinavian and other countries. Surveillance colonoscopy, to prevent colitic cancer mortality is recommended. It is common practice for performing surveillance every one to two years, eight years after onset in patients with total colitis, or after fifteen years in those with left-sided colitis. Biopsy specimens should also be taken of not only strictures and dysplasia-associated lesions or masses but also every 10 cm in the whole colorectum. Recently, Japanese investigators have tried to observe minute lesions by using dye-spray and magnifying colonoscopy and taking targeted biopsies from those lesions. |