BackgroundPre-test genetic counseling for patients with breast cancer is increasingly being provided by nongenetic healthcare professionals. We evaluated the attitudes, knowledge, and self-efficacy of surgeons, oncologists, and nurses regarding mainstream genetic testing and the feasibility to incorporate pre-test genetic counseling into routine care.MethodsWe offered an online training to healthcare professionals from 13 hospitals and implemented a mainstream genetic testing pathway in 11/13 (85%) hospitals. Questionnaires were sent before (T0) and 6 months after (T1) completing the training. Those who did not complete the training received a questionnaire to assess their motivations.ResultsIn 11 hospitals, 80 (65%) healthcare professionals completed the training, of whom 70 (88%) completed both questionnaires. The attitudes, (perceived) knowledge and self-efficacy of healthcare professionals were high both at baseline and 6 months after completing the training. After 6 months, their perceived knowledge about the advantages and disadvantages of a genetic test and implications for family members had significantly improved (p= 0.012 andp= 0.021, respectively). For the majority (89%), the time investment for pre-test genetic counseling was less than 15 min per patient and as expected or better. Healthcare professionals considered the total time investment feasible to incorporate mainstream genetic testing into their daily practice. The main barrier to complete the training was lack of time. The online training was considered useful, with a rating of 8/10.ConclusionSurgical oncologists and nurses in breast cancer care feel well-equipped and motivated to provide pre-test genetic counseling after completion of an online training module.Supplementary InformationThe online version contains supplementary material available at 10.1245/s10434-023-13229-5.