LAUSR

Abstract Background Recent advances in next generation sequencing technology helped us to test multiple germline genetic mutations simultaneously. However, because of the low frequency of pathogenic/ likely pathogenic variants beyond BRCA1/2, modest risk of cancer in the carriers of moderate penetrance genes, and lack of proper preventive strategies for the carriers, clinical application of NGS multiple panel tests still has limitations. Methods In this study, we provided sequential genetic testing and counselling programs for BRCA1/2 mutation tests and multigene panels beyond BRCA, and investigated cancer worry, genetic knowledge, and attitude towards gene panels among the patients. Results As of 28 February 2019, we prospectively enrolled 149 Korean BRCA1/2 mutation-negative female breast cancer patients with high risk for hereditary breast cancer. Median age of the patients was 42.9 (range, 21.9∼74.5) years. Among the patients, we identified 15 cases with pathogenic/ likely pathogenic variants. After genetic counselling about multigene panel, patients showed slightly decreased concern about the possibility of cancer in the future (average score of pre-, 4.32±0.808 to post-, 4.07±1.017; P = 0.003) and lower influence on mood (average score of pre-, 3.31±0.669 to post-, 3.19±0.684; P = 0.005). However, there were no changes in the average score of genetic knowledge (pre-, 0.68±0.212 to post-, 0.69±0.214; P = 0.465), and the impact of cancer worries on daily activities (pre-, 3.06±0.810 to post-, 2.97±0.699; P = 0.074). In the survey on multigene panel, 143 (96.0%) patients reported that genetic testing and counseling about multigene panel were very much (55.0%) or much (40.9%) helpful for the patients and family. 63 (42.3%) patients wanted concurrent application of BRCA1/2 mutation testing and multigene testing beyond BRCA, and 71 (47.7%) patients wanted sequential application of the tests. Conclusions Multigene panel testing and genetic counselling may help to decrease cancer worry about the possibility of cancer in the future in BRCA1/2 mutation-negative patients with high risk for hereditary breast cancer. We need to find the appropriate sequence and methods for NGS multigene panel testing and counselling programs. Legal entity responsible for the study The authors. Funding National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)(NRF-2018R1C1B6009449). Disclosure All authors have declared no conflicts of interest.