Germline genetic testing and tumor sequencing in patients with cancer

According to a study in JAMA Network Open, germline genetic testing can benefit patients with cancer even if they have had tumor DNA sequencing. In the study, researchers from Invitae, Stanford University Medical Center, and the Helen Diller Family Comprehensive Cancer Center (University of California, San Francisco) retrospectively reviewed germline testing results from 2,023 patients who had previously undergone tumor sequencing: 

  • Pathogenic germline variants were identified in 30.5% of patients. Many of these variants were clinically actionable, and 8.1% had been missed by tumor sequencing.
  • Among patients with pathogenic variants, 20% had not met criteria for follow-up testing after tumor sequencing, and 11.2% presented with a second primary cancer before their pathogenic variants were detected.
  • These results suggest that expanded germline testing should be performed in cancer patients regardless of somatic testing results because novel germline findings can impact care in appropriate patients and because somatic testing alone cannot be relied on to detect these changes.