Abstract SY09-03: Racial and ethnic differences in cancer risk models
Authors: Etzel Carol J. 
Published: August 2012

Abstract
One critical aspect of cancer prevention is the identification of high risk individuals who may benefit from active surveillance, screening trials or targeted chemoprevention. In the development, validation and application of risk models to quantify high risk, one of many questions arises, “Can one model be sufficient to estimate risk for a cancer across different populations?” In 2003, Gonzalez Burchard et al. posted to the Sounding Board section of the New England Journal of Medicine (March 20, 2003) about the importance of race and ethnic background in biomedical research. They advise that an individual's race and ethnic information is crucial for studying differences in prevalence of disease and also for the identification of different disease risk-factor profiles - an outcome of risk prediction models. In response to this posting, Swallen further pointed out that just because race is not a genetic variable, this does not mean that it is not an important one to consider in biomedical research. In contrast, Cooper et al. note that the topic of race is contentious and guards against its use as defined by genetic variants. In our lung cancer experience, we have observed that 1) prevalence of cancer varies among racial/ethnic groups, 2) different racial/ethnic groups may share environmental/occupational risk factors, but the prevalence of the risk factors and the levels of risk on the cancer of interest may be different, 3) a group that is geographically distinct may have risk factors which are unique, 4) there may exist biological differences among groups which result in varying genetic disease etiologies, 5) interactions among the varying genetic and environmental risk factors also result in varying levels of risk among groups. These observations prompted us to develop and validate group-specific risk models for lung cancer - to date, one for Caucasians, one for African Americans. The differences in risks and hence the need for group-specific risk models are not necessarily differences in socioeconomic status (SES, such as education level, income, and lack of insurance coverage) that have been implicated as the ‘sole cause’ of racial disparities in terms of cancer risk differences, but differences in key risk factors that are unrelated to SES or other economic-related factors, such as host-susceptibility, occupational and environmental exposures, genetic factors or interactions among these. While some may cite ethical dilemmas, especially in studies investigating genetic differences, and high costs associated with developing population-based and minority-specific cancer registries that could be obstacles in the development and application of group-specific risk models, we must think beyond these obstacles so that we can develop and implement the most valid and applicable models possible. In doing so, we can start to move toward personalized risk prediction, which has the promise to benefit those at the highest risks and not just those who are more likely to be randomly selected for a study. In this presentation, I will demonstrate that it is not proper to just assume that risk models constructed using data from Caucasians populations convey the same level of discriminatory power in diverse populations, but instead, it is necessary to construct group-specific risk models for application to diverse multi-racial, multi-ethnic populations. These demonstrations will be highlighted in existing risk models for lung, liver and breast cancer.
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 SY09-03. doi:1538-7445.AM2012-SY09-03