Colon cancer is more prevalent than rectal cancer, representing more than 70% of the cases when the two sites are combined. Therefore, colon cancer can be considered to dominate the calculations. The risk factors for cancers at these two segments of the intestinal tract are not well enough understood to be distinguished.
Having scanned the plots for evidence of systematic differences between the results for colon and rectal cancers and discussed the options for deriving a valid and useful conclusions, the committee agreed to conduct its meta-analyses of the epidemiologic data on colon and rectal cancers on datasets with the sites combined and to draw a single conclusion about causality for the combined sites (as stated in the Fairness in Asbestos Injury Resolution, or FAIR, legislation and the committee’s charge).
A. Results for colon cancer and asbestos exposure