Development of Genetic Testing for Breast, Ovarian and Colorectal Cancer Predisposition: A Step Closer to Targeted Cancer Prevention

Individuals who inherit a high penetrance cancer susceptibility gene represent a population in which cancer diagnoses occur at younger ages and much more frequently than in the general population. Screening regimens aimed at early detection of cancer may reduce cancer mortality but in order to reduce cancer incidence, surgery and medical therapies have been advocated. In high genetic risk patients, either surgical or medical intervention may provide long term protection against cancer and at young ages co-morbidities will be low. The use of genetic testing for high risk predisposition genes to refine risk estimates and inform choices about cancer prevention is now readily available in many countries and routinely used to target cancer prevention strategies. Surgical approaches to cancer prevention are currently the mainstay in many conditions where a high risk is identified but medical prevention strategies also have demonstrated some efficacy in lowering cancer risk. Using the genetic status of an individual to target cancer treatment and prevent recurrence is increasingly gaining momentum as clinical trials involving known high risk gene carriers are now being conducted using both established cytotoxic drugs and novel targeted agents. Translation of new mechanistic insights into beneficial clinical care strategies requires more research. Robust evidence supporting medical approaches to cancer prevention in particular will require well designed large international collaborative clinical trials.