Cancer‐linked genetic testing: Growing panels and challenges in the United States

P R O S TO C K -S TU D IO / S H U TT E R S TO C K .C O M T he roughly 1 in 300 women who carry a germline mutation in the BRCA1 gene face a roughly 70% risk of developing ovarian cancer and a 65% risk of developing breast cancer by the age of 70 years. With an inherited BRCA2 genetic mutation, the carriers face a 55% chance of developing breast cancer. For patients with what is collectively known as hereditary breast and ovarian cancer syndrome, bilateral mastectomy and hysterectomy are still the gold standards for primary prevention, although researchers are exploring less invasive alternatives. Recent studies have expanded on the idea that cancer-linked mutations may offer more targeted and less invasive prophylactic options. Researchers have pointed to MLH1 and MSH2, both of which are linked to hereditary Lynch syndrome, as part of the “first wave” of such mutations. “With screening, prevention, and early detection at the forefront of the cancer management agenda, we propose that the time is nigh for the initiation of national populationtesting programs to identify carriers of first-wave gene mutation carriers,” one group of clinicians asserted.1 Even for better studied sources of genetic risk such as hereditary breast and ovarian cancer syndrome and hereditary Lynch syndrome, however, considerable barriers are impeding initial testing. Other obstacles have limited whether the results and follow-up advice are clearly communicated and whether they trigger testing in relatives who may also be at risk. As testing protocols and gene panels continue to expand, in fact, some oncologists have questioned whether they are outpacing the field’s ability to properly counsel patients on the basis of their relative risk.