Psychosocial implications of BRCA1 and BRCA2 genetic testing for breast and ovarian cancer: a systematic review

Article type
Authors
McGahan L, Kakuma R, Joyce J
Abstract
Background: Spectrums of mutations in the BReast CAncer susceptibility genes BRCA1 and BRCA2 have been linked to the development of both breast and ovarian cancers. The analytical validity of molecular technologies and issues associated with BRCA1/2 genetic testing were examined in an effort to help patients, health care providers, hospitals, health regions and governments make informed decisions.

Objective: To discuss inherent psychosocial implications of BRCA1/2 genetic testing by assessing the evidence through a systematic review of the literature.

Method: Published and grey literature were identified from 1994 onwards by searching databases, trial registries, and the Internet, including websites of health technology assessment agencies. Primary researchers and the commercial developer were also contacted for information. A study was included if it met the eligibility criteria established a priori by two independent reviewers. Study quality was assessed and data were extracted regarding knowledge and risk perception, interest and attitudes to testing, and psychological and social issues.

Results: Of 312 articles identified, 160 were retrieved and 58 articles were included for study (kappa=0.45 original search; kappa=0.5 update). Studies were primarily single-site, cross-sectional, clinical testing in self-referred populations with unknown carrier status. Overall knowledge was limited, with physicians being the least frequently cited information source. Self-referred respondents showed higher mean knowledge scores than patient referrals. Individuals (70-82%) were interested in testing; however, most overestimate their risk of carrying a mutation. Significant psychological (distress, depression, emotional reactions) and social (disclosure, family planning, communication) effects may be experienced regardless of carrier status. Distress was highest in carriers, yet anxiety decreased following disclosure of results, irrespective of status. Carriers informed their sisters 96% of the time.

Discussion: Diversity in study designs, populations, outcome measures and quality of studies precluded quantitative comparison of the data from selected studies. Self-referral contributes to selection bias, limiting the generalizability of some results. Measurement bias may have occurred where testers had prior knowledge of carrier status. By providing decision makers with relevant information about the psychosocial implications of testing and limitations in this evidence, we may provide them with greater context when planning further research and resources, and developing policies.