Genetic testing in gastrointestinal cancers: a case-based approach.
High-risk genetic mutations that predispose individuals to various gastrointestinal (GI) cancers account for only about 5% of the population burden of these diseases. However, because early identification of at-risk individuals can so dramatically affect primary disease prevention, it is imperative that families who harbor susceptibility to these cancers be identified. The benefits of determining an underlying genetic susceptibility are important both for an individual patient's ongoing management and for his or her family, where early identification of at-risk persons, along with the adoption of frequent cancer screenings and/or prophylactic risk-reduction surgeries, can have dramatic life-prolonging benefits. In this article, we use a case-based approach to focus on the hereditary aspects of the most common GI cancers, including pancreatic, gastric, and colon cancer.