Given the accumulating evidence documenting the efficacy of genetic screening and risk-reduction interventions, genetic cancer risk assessment (GCRA) has become a medical standard-of-care option for persons with a personal and/or family history of cancer suggestive of increased cancer risk.1-5 GCRA utilizes rapidly evolving genetic technologies along with established empiric risk models to estimate cancer risk and provide age- and risk-level appropriate cancer prevention and risk-reduction strategies for individuals and their family members. The ultimate value of GCRA is the opportunity for initiation of early detection or risk-reducing strategies that would be most effective in minimizing cancer incidence, morbidity, and mortality, by identifying persons at increased cancer risk prior to the onset of an initial or subsequent cancer.
The GCRA process includes assessing personal and family medical history and family structure6 to determine individual cancer risks and the probability of an inherited genetic trait accounting for cancer in an individual and/or the individual's family and counseling about the appropriateness, benefits, limitations, risks, and process of genetic testing and subsequent health care implications. If genetic testing is undertaken and a deleterious mutation identified, single-site mutation testing in other at-risk family members adds relatively little cost while maximizing benefits to families by distinguishing relatives at high risk from those at modest or average risk. Relatives who did not inherit the familial mutation can then be spared the personal and economic cost of unnecessary interventions.7
The greatest experience and application of GCRA to date is in the evaluation of hereditary breast cancer. Quantification of risk from informative genetic testing enables women to choose among risk-reducing interventions such as chemoprevention, mastectomy, and/or bilateral salpingo-oophorectomy, enhanced and earlier surveillance, and healthier lifestyle choices.8-20 For patients who undergo genetic testing but do not have a detectable cancer-associated mutation, who decline testing, or are unable to proceed with genetic testing due to financial or other reasons, a variety of empiric risk models may be used to quantify risk and provide individualized recommendations for cancer screening and risk-reduction. Similarly, the discovery of other single genes involved in early onset-colon cancer or other heritable cancer-associated syndromes (eg, multiple endocrine neoplasia) enables prevention, risk-reduction, or earlier diagnosis of cancer through identification of high-risk individuals. As such, GCRA has an important role in guiding patient decision-making.4,17,18 Recognizing the value of GCRA, genetic counseling and testing was added as a supportive service to the 2004 American College of Surgeons (ACS) Commission on Cancer, Cancer Program Standards.21 Consequently, community-based cancer centers are integrating GCRA into oncology care. State-of-the-art quality care, including access to innovative research, may be achieved by partnering with a comprehensive cancer center with a robust GCRA program.22 This chapter describes essential components of a cancer genetics service and various models of service delivery utilized by community centers affiliated with a cancer genetics center of excellence.
The author thanks Jeffrey N. Weitzel, MD and Sharon Sand, CCRP for critical ...