Genetic testing in patients with triple-negative or hereditary breast cancer

In recent years there has been a dramatic evolution in the clinical utility of genetic testing with expanding therapeutic implications for individuals with breast cancer who harbor a germline mutation in BRCA1/2. As these therapeutic opportunities expand and evolve, this requires the clinical and research community to rethink the approach to genetic testing for individuals with breast cancer.

Genetic testing is evolving from traditional testing models based on pretest counseling with the aim of identifying hereditary and individual risk for purposes of screening and risk reduction to contemporary models that utilize technology to improve accessibility and oncology led mainstreaming of testing where the oncologist refers for genetic testing, discloses the results and formal counseling occurs later in the process than in traditional models. The cost and accessibility to multigene panel testing have resulted in broad uptake despite the fact that clinical utility and appropriate interpretation of results are not yet well established. Furthermore, somatic testing for genomic alterations may also yield results beyond the disease with detection of germline mutations impacting the individual and their family more broadly than anticipated.

With the establishment of poly (adenosine diphosphate-ribose) polymerase inhibitors as part of the treatment armamentarium for early and advanced breast cancer, paradigms, algorithms, and resources for genetic testing need to rapidly change in order to adapt to the evolution of germline mutations from hereditary and individual risk predictors to predictive therapeutic biomarkers.