Clinical Relevance of Multigene Sequencing in Patients With Breast Cancer
Posted: Thursday, August 2, 2018
Recent trends indicate that patients diagnosed with stages 0 to II breast cancer opt for multigene sequencing over the traditional sequencing of two breast cancer–related genes, BRCA1 and BRCA2. Compared with BRCA1/2-only tests, multigene sequencing allowed for twofold higher detection of clinically relevant pathogenic variants. These findings, published in the JAMA Oncology, suggest multigene sequencing can be a valuable resource for patients with breast cancer and their families.
“Multigene panel tests are more likely than BRCA-only tests to yield information about both a patient and her family members, who may be unwitting carriers of disease-associated mutations” revealed lead study author Allison W. Kurian, MD, of Stanford University School of Medicine, in a Stanford Medicine news release. Patients should “advocate for the opportunity to discuss genetic testing and its implications with an experienced clinician, such as a genetic counselor, in a timely manner.”
More than 5,000 patients, reported to the Georgia or Los Angeles County Surveillance, Epidemiology, and End Results (SEER) registries, were surveyed over the course of 2 years (2013–2015). The rate of multigene sequencing increased from 4.8% to 19.6%, replacing BRCA1/2-only testing, as its rate decreased from 22.6% to 10%. However, multigene sequencing revealed a 10-fold increase in variants with unknown significance, especially in racial/ethnic minority groups.
In addition, the investigators noted a timing disparity in multigene sequencing. Most patients received multigene panel testing before tumor-removal surgery, but many (33%) were tested after surgery. These findings reinforce the need for diverse research populations and genetic experts integrated early in the care for patients with cancer.