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Genetic counselling for hereditary breast cancer

1999; Elsevier BV; Volume: 353; Issue: 9171 Linguagem: Inglês

10.1016/s0140-6736(99)90078-8

1474-547X

Beth N. Peshkin, Caryn Lerman,

Family Support in Illness

Although initial interest in gene testing seemed to be substantial,1Lerman C Daly M Masny A Balshem A Attitudes about genetic testing for breast-ovarian cancer susceptibility.J Clin Oncol. 1994; 12: 843-850Crossref PubMed Scopus (451) Google Scholar studies in high-risk families have shown that the uptake is below 50%. The largest of these studies revealed that of 279 individuals from 13 families, only 43% decided to receive BRCA1 test results.2Lerman C Narod S Schulman K et al.BRCA1 testing in families with hereditary breast-ovarian cancer: a prospective study of patient decision-making and outcomes.JAMA. 1996; 275: 1885-1892Crossref PubMed Google Scholar This finding was similar to the 41% uptake rate noted in two families participating in BRCA1 linkage studies.3Watson M Lloyd SM Eeles R et al.Psychosocial impact of testing (by linkage) for the BRCA1 breast cancer gene: an investigation of two families in the research setting.Psycho-Oncol. 1996; 5: 233-239Crossref Scopus (44) Google Scholar However, another small study found that 80% of 29 members of two BRCA1 families accepted genetic testing.4Patenaude AF Schneider KA Kieffer SA et al.Acceptance of invitations for p53 and BRCA1 predisposition testing: factors influencing potential utilization of cancer genetic testing.Psycho-Oncol. 1996; 5: 241-250Crossref Google Scholar Factors that may influence decisions include the strength of the family history, the perception of the benefits of testing, and the estimation of risk of being a gene carrier.2Lerman C Narod S Schulman K et al.BRCA1 testing in families with hereditary breast-ovarian cancer: a prospective study of patient decision-making and outcomes.JAMA. 1996; 275: 1885-1892Crossref PubMed Google Scholar In a report highlighting some of the challenges associated with genetic counselling for women at increased risk of breast cancer, M Watson and colleagues emphasise that a woman's perception of this risk may influence both her attitude to screening and her psychological well-being.5Watson M Lloyd S Davidson J et al.The impact of genetic counselling on risk perception and mental health in women with a family history of breast cancer.Br J Cancer. 1999; 79: 868-874Crossref PubMed Scopus (213) Google Scholar The increasing availability of genetic testing should offer opportunities to improve assessment of this risk and how it is imparted to patients. Women who seek genetic counselling and testing may represent a psychologically vulnerable group in that they may exhibit more cancer-specific distress or mood disturbances.1Lerman C Daly M Masny A Balshem A Attitudes about genetic testing for breast-ovarian cancer susceptibility.J Clin Oncol. 1994; 12: 843-850Crossref PubMed Scopus (451) Google Scholar, 5Watson M Lloyd S Davidson J et al.The impact of genetic counselling on risk perception and mental health in women with a family history of breast cancer.Br J Cancer. 1999; 79: 868-874Crossref PubMed Scopus (213) Google Scholar Although test-related distress may increase immediately after results are disclosed,6Croyle RT Smith KR Botkin JR Baty B Nash J Psychological responses to BRCA1 mutation testing: preliminary findings.Health Psychol. 1997; 16: 63-72Crossref PubMed Scopus (295) Google Scholar early data from high-risk families have shown no significant increases in global distress or anxiety among mutation carriers.2Lerman C Narod S Schulman K et al.BRCA1 testing in families with hereditary breast-ovarian cancer: a prospective study of patient decision-making and outcomes.JAMA. 1996; 275: 1885-1892Crossref PubMed Google Scholar However, once a BRCA1 or BRCA2 mutation has been found, family members who are distressed about their risk, yet decline testing, may be more likely than those tested to experience adverse psychological effects, irrespective of whether the test results were positive or negative.7Lerman C Hughes C Lemon SJ et al.What you don't know can hurt you: adverse psychological effects in members of BRCA1-linked and BRCA2-linked families who decline genetic testing.J Clin Oncol. 1998; 16: 1650-1654PubMed Google Scholar Because families in these research studies were highly selected, the findings may not apply to clinic-based populations, in which family experience with cancer may be more limited and for whom the service provided may be less extensive. Most women with no history of breast or ovarian cancer who test positive for a BRCA mutation do not intend to have prophylactic surgery, at least in the short-term.2Lerman C Narod S Schulman K et al.BRCA1 testing in families with hereditary breast-ovarian cancer: a prospective study of patient decision-making and outcomes.JAMA. 1996; 275: 1885-1892Crossref PubMed Google Scholar Thus, reinforcement of conventional screening and other risk-reduction options is important.8Burke W Daly M Garber J et al.Recommendations for follow-up care of individuals with an inherited predisposition to cancer-II: BRCA1 and.BRCA2. JAMA. 1997; 277: 997-1003Crossref PubMed Google Scholar Initial anxiety about the potential risk of cancer6Croyle RT Smith KR Botkin JR Baty B Nash J Psychological responses to BRCA1 mutation testing: preliminary findings.Health Psychol. 1997; 16: 63-72Crossref PubMed Scopus (295) Google Scholar may prevent women from seeking early detection, thus genetic counselling may need to be followed by psychological interventions. Informed consent for women considering genetic testing must include not only the benefits and risks of testing but also the uncertainties of risk assessment and medical decision-making. Models to estimate an individual woman's probability of carrying a BRCA1 or BRCA2 mutation are being developed9Parmigiani G Berry DA Aguilar O Determining carrier probabilities for breast cancer-susceptibility genes BRCA1 and BRCA2..Am J Hum Genet. 1998; 62: 145-158Summary Full Text Full Text PDF PubMed Scopus (619) Google Scholar (panel) and, in view of the expense of testing and the possibility of uninformative results, such estimates may be useful. In addition, cancer-risk estimates may be tailored on the basis of the specific mutation identified, the impact of potential modifier genes such as CYP1A1 and HRAS1, and gene-environment interactions (eg, reproductive factors and hormone use). Long-term outcome data will also become available for the assessment of the efficacy of screening and prevention options. Also, whether tamoxifen reduces breast-cancer risk in BRCA1 or BRCA2 carriers and what level of risk reduction is conferred by prophylactic surgery are not known. Such information is critical to informed decision-making.PanelResearch issues in genetic counselling for hereditary breast cancerValidation of probability models for mutation detection Correlations between genotype and phenotype (clinical outcome)Role of genetic and other risk factors that modify penetranceEfficacy of early detection and prevention strategies Cost-effectiveness of genetic counselling and testing Long-term impact of testing on emotional well-being and medical decisionsOptimum methods of genetic counselling and presentation of risk informationAdjunctive methods of education and psychological counselling Validation of probability models for mutation detection Correlations between genotype and phenotype (clinical outcome)Role of genetic and other risk factors that modify penetranceEfficacy of early detection and prevention strategies Cost-effectiveness of genetic counselling and testing Long-term impact of testing on emotional well-being and medical decisionsOptimum methods of genetic counselling and presentation of risk informationAdjunctive methods of education and psychological counselling The best way of obtaining informed consent and providing genetic counselling is also being explored. Several studies, including that by Watson and colleagues,5Watson M Lloyd S Davidson J et al.The impact of genetic counselling on risk perception and mental health in women with a family history of breast cancer.Br J Cancer. 1999; 79: 868-874Crossref PubMed Scopus (213) Google Scholar show that women find it difficult to retain the quantitative risks provided during genetic counselling, so other ways of delivering this information need to be investigated. Also needed is information on whether comprehension, compliance with screening guidelines, and psychological adjustment can be improved by expansion of the genetic-counselling sessions. Videotapes and interactive computer programs10Cull A Miller H Porterfield T et al.The use of videotaped information in cancer genetic counselling: a randomized evaluation study.Br J Cancer. 1998; 77: 830-837Crossref PubMed Scopus (108) Google Scholar may be useful adjuncts, for example; tools to identify individuals most likely to experience adverse effects from genetic testing and those who might benefit from the addition of psychosocial interventions would also be useful. Some women, especially those from high-risk families, have already chosen to undergo genetic testing for hereditary breast cancer despite the many uncertainties. Experience from carefully monitored research protocols is providing important information about who wants this test and how test results affect medical and psychosocial outcomes. Answers to questions in molecular genetics and genetic epidemiology that will have important implications for clinicians can be expected. The process of genetic counselling will have to be continuously refined and supplemented so that the benefits of genetic testing for women can be increased while the potential for harm is reduced.