Background: Colorectal cancer is a main leading cause of cancer death in western countries. Although manystudies have been conducted on incidence trends all over the world in recent years, information regarding changesin incidence of colorectal cancer in Iran is insufficient. The present study of colorectal cancer in the west of Iranduring recent years was therefore performed. Materials and Methods: The registered data for colorectal cancercases in National Cancer Registry System were extracted from the Ministry of Health and Medical Education,Center for Disease Control and Management. The codes from 18-21 among cancers were selected for colon andrectum cancers. Incidence rates were standardized directly using WHO population. The significance of incidencerate trends during 2000-2005 was tested through Poisson regression. Results: 762 cases of colorectal cancer wereobserved during 6 years in this region, with a gender ratio of men to women of 1.2. It increased from 65 casesin 2000 to 213 cases in 2005 or from 1.5 per100,000 per persons per year to 4.8. Significant increasing trendswere evident in Kermanshah and Hamadan provinces; however, change did not reach significance in Ilam andKurdistan provinces. Conclusions: Colorectal cancer has an increasing trend in the west of Iran. Although itseems that the increasing rate of colorectal cancer is due to increasing of cancer risk factors, some proportionmay be related to the improvement of surveillance systems in Iran.
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