We investigated the association of colorectal cancer risk factors with different colorectal cancer subsites to assess etiological differences for cancers of the proximal colon, distal colon, and rectum. Included in this study were 869,725 men and 395,501 women who participated in a health examination provided by the Korean National Health System between 1996 and 1997. During up to 7 years of follow-up, 4,144 incident colorectal cancer cases were detected (3,051 men and 1,093 women). Greater height was associated with elevated risk for distal colon cancer and rectal cancer in both men and women. Family history of cancer was associated with higher risk for cancers of the proximal colon in men and distal colon in both men and women. Frequent alcohol consumption and consuming high amounts of alcohol were associated with elevated risk for distal colon cancer in men and higher risk for rectal cancer in women. Frequent meat consumption was associated with risk for proximal colon cancer in men and for rectal cancer in women. Our findings suggest that risk factors for colorectal cancer are different by subsites of colon and rectum, as well as by sex.

PurposeIncidence and mortality rates of colorectal cancer have been rapidly increasing in Korea during last few decades. Development of risk prediction models for colorectal cancer in Korean men and women is urgently needed to enhance its prevention and early detection.MethodsGender specific five-year risk prediction models were developed for overall colorectal cancer, proximal colon cancer, distal colon cancer, colon cancer and rectal cancer. The model was developed using data from a population of 846,559 men and 479,449 women who participated in health examinations by the National Health Insurance Corporation. Examinees were 30–80 years old and free of cancer in the baseline years of 1996 and 1997. An independent population of 547,874 men and 415,875 women who participated in 1998 and 1999 examinations was used to validate the model. Model validation was done by evaluating its performance in terms of discrimination and calibration ability using the C-statistic and Hosmer-Lemeshow-type chi-square statistics.ResultsAge, body mass index, serum cholesterol, family history of cancer, and alcohol consumption were included in all models for men, whereas age, height, and meat intake frequency were included in all models for women. Models showed moderately good discrimination ability with C-statistics between 0.69 and 0.78. The C-statistics were generally higher in the models for men, whereas the calibration abilities were generally better in the models for women.ConclusionsColorectal cancer risk prediction models were developed from large-scale, population-based data. Those models can be used for identifying high risk groups and developing preventive intervention strategies for colorectal cancer.

Objective: To date, there have been few prospective cohort studies that have investigated the association between dietary factors and the risk of esophageal cancer (EC). A large population-based cohort study was conducted to assess the effect of dietary factors on the risk of EC in Korean adults. Methods: The data for this study came from the National Health Insurance Corporation Study (NHICS), Korean Central Cancer Registry. The participants aged 30-80 years were 822,745 Korean men and 368,918 women, cancer-free at baseline in 1996 and 1997, and were followed up to December 31, 2007. The hazard ratio (HR) and 95% confidence interval (CI) of the HR were estimated using the Cox proportional hazards regression model. Results: During the follow-up period, crude incidence rates per 100,000 person-years for EC were 8.1 in overall total population, 11.1 in men, and 1.2 in women. In the total population, the estimated HRs (95% CI) for meat consumption of more than 4 times per week compared with consumption of less than once per week were 1.267 (1.018-1.577) with a p value of 0.0337. In men only groups, the HRs (95% CI) for those who had irregular meal patterns compared with those with regular meal patterns were 1.359 (1.087-1.699) with a p value of 0.0071. Conclusion: The present findings suggest that dietary factors may be associated with the risk of EC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5433. doi:1538-7445.AM2012-5433

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<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.