Colorectal cancer screening for persons at average risk

Abstract

Despite universal endorsement of CRC screening, less than half the average-risk population over age 50 has undergone a CRC screening examination of any type. Nevertheless, the adenoma-to-carcinoma sequence is a long-term, multistep continuum that provides a compelling biologic rationale, opportunity-and even responsibility (90,91)-for CRC screening and prevention. Therefore, a primary challenge is to investigate and address barriers to the implementation of routine CRC screening guidelines. Additional research efforts should focus on determining the preferred strategy for detecting adenomas. It is not clear that all strategies would have a favorable therapeutic index or could be applied to the general population. A head-to-head comparison of available technologies in a randomized clinical trial with a CRC mortality endpoint would be the most direct approach to this issue. Although evidence from a randomized clinical trial would provide the type of evidence that could favorably affect screening behavior, its feasibility is limited because of the long duration, large sample size, high cost, and low subject and provider acceptance that such a study may encounter. In the absence of such a long-term, large-scale colonoscopy randomized clinical trial, smaller, less costly trials that estimate new and emerging technologies against reasonable surrogate endpoint biomarkers (i.e., any adenoma and advanced adenomas) should be considered to assess relative efficacies, as well as to answer important biologic questions relating to pre-invasive colorectal neoplasia.