Genetic testing in women with early-onset breast cancer: a Traceback pilot study.

In Sweden, a Traceback approach, i.e., a retrospective genetic outreach activity, among cancer patients is not normally used in clinical practice. In this pilot study, we wanted to evaluate a Traceback strategy for possible future clinical implementation and investigate why not all women with early-onset breast cancer underwent genetic testing when they were first diagnosed. Out of all women (n = 409) diagnosed with breast cancer at ≤ 35 years in Southern Sweden between 2000 and 2017, 63 had not previously been tested. These women were offered an analysis of the genes BRCA1, BRCA2, PALB2, CHEK2, and ATM through a standardized letter. Subsequently, women with normal test results were informed through a letter and carriers of pathogenic variants were contacted through a telephone call and offered in-person genetic counseling. All tested women were asked to complete a follow-up questionnaire regarding previously not having attended genetic counseling and testing and their experiences of the current retrospective approach. Out of the invited women, 29 (46%) underwent genetic testing and 27 (43%) answered the questionnaire. Pathogenic variants were identified in BRCA1 (n = 2), CHEK2 (n = 1), and ATM (n = 1). The main reason for previously not having undergone genetic testing was not having received any information from their physicians. Most study participants were satisfied with both written pre- and post-test information. The process with retrospective identification, written pre-test information, and genetic testing, followed by in-person counseling for carriers of pathogenic variants only, was well accepted. This has implications for future Traceback implementation programs.