Abstract LB-396: Site-specific risk factors for colorectal cancer among Korean population
Authors: Shin Aesun , Bak Jeongin , Kim Jeongseon , Park Sohee , Nam Byung-Ho 
Published: February 2011

Abstract
Colorectal cancer incidence and mortality have been gradually increasing during the last few decades in Korea. Growing evidences revealed etiological differences among proximal colon, distal colon, and rectal cancer. Furthermore, the proportion of rectal cancer among colorectal cancer incidence in Korean people is over 40%. This is relatively high compared to that observed among Western population. We investigated the association between colorectal cancer risk factors and different sites of colorectal cancers based on a large Health Insurance Study.
Included in this study were 869,725 men and 395,501 women who were beneficiaries or dependent family members of the insured who were cancer-free at baseline between 1996 and 1997, participating in the National Health Insurance Corporation Study (NHICS) were followed for up to 7 years. The Cox proportional hazard model was used to estimate hazard ratios (HR) and their 95% confidence intervals (CI) with adjustment for age. During up to 7 years of follow-up, 4,144 incident colorectal cancer cases were detected (3,051 men and 1,093 women). Height was associated with an elevated risk for left colon cancer and rectal cancer in men (HR=1.02, 95% CI=1.01-1.03 for left colon cancer and HR=1.01, 95% CI=1.00-1.02 for rectal cancer, per 1 cm increments) and that for rectal cancer in women (HR=1.03, 95% CI=1.01-1.04, per 1 cm increments). Family history of cancer was associated with a higher risk for cancer of right colon (HR=1.40, 95% CI=1.14-1.72) and left colon (HR=1.31, 95% CI=1.12-1.55) in men, and for cancer of left colon (HR=1.57, 95% CI=1.20-2.06) in women. Frequent alcohol consumption and high consumption amount were associated with an elevated risk for left colon cancer in men. Men who consumed alcoholic beverages 3-4 times per week showed 1.65-fold increase risk for left colon cancer compared to non-drinkers (95% CI=1.32-2.06, p-trend&lt;0.001). Whereas frequent alcohol consumption was associated with a higher risk for rectal cancer in women (HR=2.75, 95% CI=1.61-4.71 for almost every day vs. non-drinkers). Frequent meat consumption was associated with risk for right colon cancer in both men (HR=1.37, 95% CI=0.99-1.91 for ≥4 times/week vs. ≤1 time/week) and women (HR=1.72, 95% CI=1.11-2.66 for ≤4 times/week vs. ≤1 time/week), and that for rectal cancer in women (HR=1.46, 95% CI=1.05-2.03 for ≥4 times/week vs. ≤1 time/week). Our findings support the hypothesis of differential risk factor profiles according to subsites of colorectum, and suggest that colon cancer is more susceptible to host factors such as family history of cancers, and distal colon cancer and rectal cancer are more susceptible to environmental risk factors such as alcohol consumption.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-396.