How much can current interventions reduce colorectal cancer mortality in the US? Mortality projections for scenarios of risk-factor modification, screening, and treatment

BACKGROUND. Although colorectal cancer (CRC) is the second leading cause of cancer death in the U.S., available interventions to reduce CRC mortality are disseminated only partially throughout the population. This study assessed the potential reduction in CRC mortality that may be achieved through further dissemination of current interventions for risk-factor modification, screening, and treatment. METHODS. The MISCAN-COLON microsimulation model was used to simulate the 2000 U.S. population with respect to CRC risk-factor prevalence, screening use, and treatment use. The model was used to project age-standardized CRC mortality from 2000 to 2020 for 3 intervention scenarios. RESULTS. Without changes in risk-factor prevalence, screening use, and treatment use after 2000, CRC mortality would decrease by 17% by the Year 2020. If the 1995 to 2000 trends continue, then the projected reduction in mortality would be 36%. However, if trends in the prevalence of risk factors could be improved above continued trends, if screening use increased to 70% of the target population, and if the use of chemotherapy increased among all age groups, then a 49% reduction would be possible. Screening drove most (23%) of the projected mortality reduction with these optimistic trends; however, decreasing risk factors (16%) and increasing use of chemotherapy (10%) also contributed substantially. The contribution of risk factors may have been overestimated, because effect estimates could not be obtained from randomized controlled trials. CONCLUSIONS. Currently available interventions for risk-factor modification, screening, and treatment have the potential to reduce CRC mortality by almost 50% by the Year 2020. However, without action now to further increase the uptake of current effective interventions, the reduction in CRC mortality may be only 17%.