A study group from Melbourne, Australia conducted a Prospective study of women with invasive or high grade in situ breast cancer and unknown germline status and the same discussed at the multidisciplinary team meeting. Women were recruited to the pilot (12 June 2020 - 22 March 2021) and expansion phases (17 October 2021 - 8 November 2022) of the Mutational Assessment of newly diagnosed breast cancer using Germline and tumour genomICs (MAGIC) study to determine the feasibility of universal genetic testing of women with newly diagnosed breast cancer, to estimate the incidence of pathogenic gene variants and their impact on patient management, and to evaluate patient and clinician acceptance of universal testing.The study group identified pathogenic germline variants in 31 of 474 expanded study phase participants (6.5%), including 28 of 429 women with invasive breast cancer (6.5%).
18 of the 31 did not meet current genetic testing eligibility guidelines (probability of a germline pathogenic variant ≥ 10%, based on CanRisk, or Manchester score ≥ 15). In 24 of 31 women clinical management was changed for after identification of a pathogenic variant. Further, 68 women who underwent genetic testing outside the study, 44 of 542 women carried pathogenic variants (8.1%).
“Acceptance of universal testing was high among both patients (90 of 103, 87%) and clinicians; no decision regret or adverse impact on psychological distress or cancer-specific worry were reported as per the investigators”
Finally, universal genetic testing following the diagnosis of breast cancer detects clinically significant germline pathogenic variants that might otherwise be missed because of testing guidelines. Routine testing and reporting of pathogenic variants is feasible and acceptable for both patients and clinicians.