ObjectiveWomen with hereditary breast and ovarian cancer syndrome (HBOC) face a higher risk of earlier, more aggressive cancer. Because of HBOC's rarity, screening is recommended only for women with strong cancer family histories. However, most patients do not have accurate history available and struggle to understand genetic concepts.MethodsCancer in the Family, an online clinical decision support tool, calculated women's HBOC risk and promoted shared patient–provider decisions about screening. A pilot evaluation (n = 9 providers, n = 48 patients) assessed the tool's impact on knowledge, attitudes, and screening decisions. Patients used the tool before wellness exams and completed three surveys. Providers accessed the tool during exams, completed exam checklists, and completed four surveys.ResultsPatients entered complete family histories (67%), calculated personal risk (96%), and shared risk printouts with providers (65%). HBOC knowledge increased dramatically for patients and providers, and many patients (75%) perceived tool results as valid. The tool prompted patient–provider discussions about HBOC risk and cancer family history (88%).ConclusionsThe tool was effective in increasing knowledge, collecting family history, and sparking patient–provider discussions about HBOC screening.Practice implicationsInteractive tools can effectively communicate personalized risk and promote shared decisions, but they are not a substitute for patient–provider discussions.