Germline Genetic Testing 'Underused' in Colorectal Cancer Patients

In JAMA Network Open, investigators from Invitae, Optum Labs, UnitedHealthcare, and Variantyx look at germline genetic testing uptake and outcomes in colorectal cancer (CRC) patients diagnosed before or after a 2020 change that saw a boost in insurance coverage for such tests in newly diagnosed CRC cases. Using insurance claims and billing data, the team assessed germline genetic testing and microsatellite instability (MSI)/immunohistochemistry (IHC)-based testing for DNA mismatch repair (MMR) defects in CRC cases diagnosed between early 2017 and the end of 2020. In a group of 9,066 eligible individuals with CRC during that time frame, the authors saw MSI/IHC testing for MMR in more than 73 percent of patients. In contrast, just 3 percent of CRC patients got broader germline genetic testing in a larger group of almost 55,600 CRC cases diagnosed in 2020. "This nationwide cohort study found suboptimal rates of MSI/IHC screening and germline genetic testing uptake, resulting in clinically actionable genetic data being unavailable to patients diagnosed with CRC, despite universal eligibility," they write. "Effective strategies are required to address barriers to implementation of evidence-based universal testing policies that support precision treatment and optimal care management for patients with CRC."