BackgroundWomen with inherited mutations in theBRCA1orBRCA2genes have increased lifetime risks for developing breast and/or ovarian cancer and may develop these cancers around the age of 30 years. Therefore, prevention of breast and ovarian cancer in these women may need to start relatively early in life. In this study we systematically evaluate the long-term effectiveness and cost effectiveness of different prevention strategies for breast and ovarian cancer in women withBRCA-1/2mutation in Germany.MethodsA decision-analytic Markov model simulating lifetime breast and ovarian cancer development inBRCA-1/2carriers was developed. Different strategies including intensified surveillance (IS), prophylactic bilateral mastectomy (PBM), and prophylactic bilateral salpingo-oophorectomy (PBSO) alone or in combination at different ages were evaluated. German clinical, epidemiological, and economic (in 2022 Euro) data were used. Outcomes included cancer incidences, mortality, life years (LYs), quality-adjusted life years (QALYs), and discounted incremental cost-effectiveness ratios (ICER). We adopted the German health-care system perspective and discounted costs and health effects with 3% annually.ResultsAll intervention strategies are more effective and less costly than IS alone. Prevention with PBM plus PBSO at age 30 maximizes life expectancy with 6.3 LYs gained, whereas PBM at age 30 with delayed PBSO at age 35 improves quality of life with 11.1 QALYs gained, when compared to IS alone. A further delay of PBSO was associated with lower effectiveness. Both strategies are cost effective with ICERs significantly below 10,000 EUR/LYG or QALY.ConclusionBased on our results, PBM at age 30 plus PBSO between age 30 and 40 prolongs life and is cost effective in women withBRCA-1/2mutations in Germany. Serial preventive surgeries with delayed PBSO potentially improve quality of life for women. However, delaying PBM and/or PBSO further may lead to increased mortality and reduced QALYs.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12885-023-10956-6.