Purpose: This study seeks to identify the independent predictive roles of selected demographic variables for invasive colorectal cancer (CRC) sub-sites.

Methods: Demographic and sub-site variables were extracted from the California Cancer Registry (CCR) for 117,354 invasive colon cancer cases diagnosed from 2001–2008. Stratified and Logistic regression analyses were used to distinguish individual predictive effects of demographic variables on odds of CRC in contrasting bowel segments.

Results: Multivariable odds ratios (OR) for binary bowel segment categories contrasting <40 (OR =1.20; 95% CI =1.11-1.30), 40–49 (1.48; 95% =1.41-1.55) and 75+ (0.54; 0.53–0.56) relative to age 50–74 years reveal independent associations. Contrast with non-Hispanic white, ORs for left to non-left bowel cancer were 1.68; 95% CI =1.56-1.81 (Asian/Other), 0.73; 0.62–0.84 (non-Hispanic black) and 1.12; 1.01–1.24 (Hispanic). Females showed lower odds of left to non-left bowel cancer than males (OR =0.75 CI =0.73-0.77). Descending ORs were seen for sequentially lower SES quintiles (OR1:5 = 1.11; 1.05–1.17, OR2:5 = 1.07; 1.02–1.12, OR3:5 = 1.02; 0.978–1.06 and OR4:5 = 0.98; 0.94–1.02) (Trend p <0.0001) adjusting for other covariates. No significant multiplicative interaction was detected between race/ethnicity and SES variables. Findings were similar for contrasts of distal to non-distal and sigmoid colon to non-sigmoid CRC.

Conclusions: Younger than age 50–74; male gender; Asian/Other or Hispanic ethnicity, and lower SES were each independent predictors of left to non-left CRC. Progressively lower SES showed an inverse dose-response relationship with odds of left to non-left CRC, independent of other covariates. These findings reveal demographic predictors of CRC bowel segment origin that may influence screening success.

Funding: The California Department of Public Health, National Cancer Institute (Grant N01-PC-35136 and N01-PC-35139), and Centers for Disease Control & Prevention (CDC) (Grant N02-PC-54404) funded cancer surveillance necessary for this study.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B71.

Copyright © September 18, 2011, American Association for Cancer Research
2011