Numerous genetic mutations are linked to increased risk for breast cancer. Genetic testing can identify these mutations and guide patient management decisions. Over the past decade, multi-gene panel tests have gained traction in clinical settings. These evaluate up to 43 breast cancer-related genes, compared with limited BRCA 1 and BRCA2 (BRCA1/2) tests. In a recent review for World Journal of Surgical Procedures, I discussed whether multi-gene panel testing should replace limited BRCA1/2 testing.
Background to Genetic Testing
Since the mid-1990s, we have known about the link between BRCA1/2 and risk for breast cancer, which account for 30 to 50 percent of breast cancers. There are now well-established clinical guidelines for the management of patients with BRCA1/2 mutations and testing is often covered by insurance.
Over the past decade, our knowledge of cancer biology has grown tremendously and we now know of more than 40 genes linked to increased risk for breast, ovarian, and other cancers. Several multi-gene panel tests are available to patients. These can effectively evaluate BRCA1/2 in addition to up to 43 other cancer-related genes.
Multi-Gene Panel Testing Vs. Limited BRCA1/2 Testing
In the past, genetic testing required initial BRCA1/2 testing followed by sequential testing for other breast cancer-related genes. The benefits to multi-gene panel testing are clear. Multi-gene panel testing offers greater likelihood of identifying patients with cancer-related mutations, improved efficiency and lower overall cost.
There are some drawbacks to multi-gene panel testing, at least for now. One is higher rates of inconclusive results compared with limited BRCA1/2 testing. This can make management recommendations difficult for clinicians and cause patients anxiety about future risks to themselves and their families.
Another drawback is that guidelines for testing and management of many non-BRCA1/2 genes aren’t as clearly established as for BRCA1/2. The National Comprehensive Cancer Network provides detailed recommendations for PTEN, TP53, CDH1 and STK11 and considerations for ATM, CHEK2 and PALB2. However, larger population-based and family-based studies should lead to more definitive management recommendations.
Despite the existing drawbacks to multi-gene panel tests, there are clear advantages over limited BRCA1/2 testing. As research reveals more information about cancer biology and genetic risk, we will be better able to make clear management recommendations to our patients. For now, clinicians should thoughtfully use multi-gene panel tests and results according existing guidelines to manage patients with non-BRCA1/2 pathogenic mutations.
To read the complete review, please visit wjgnet.com.