Notícias Médicas

Estudo testes genéticos para mulheres com alto risco de mutações

Por Dra. Alessandra Borba A. de Souza

Um recente estudo revelou que médicos costumam não recomendar ou, até mesmo, discutir testes genéticos para mulheres com alto risco de mutações associadas ao câncer de mama ou de ovários. "Mulheres têm muito interesse em testes genéticos, mas muitas não recebem indicação para fazê-los", afirmou Allison Kurian, professora de Medicina na Universidade de Stanford e principal autora do estudo publicado no JAMA, o Jornal da Associação Americana de Medicina.

"Isso é particularmente preocupante porque significa que os médicos estão perdendo a oportunidade de prevenir o câncer em portadoras de mutações e membros da família", acrescentou.

Kurian e pesquisadores da Universidade de Michigan basearam seus achados em uma consulta com mais de 2.500 mulheres com câncer nos estágios 0 a 2, dois meses após terem se submetido à cirurgia. Elas foram questionadas se gostariam de fazer um teste genético para ver a presença de mutações nos genes BRCA 1 e BRCA 2 e, caso sim, se o fizeram.

Dois terços das mulheres afirmaram que gostariam de fazer o teste, mas apenas um terço havia feito. Cerca de 56% das que não realizaram o teste afirmaram que não fizeram porque seus médicos não recomendaram. Apenas 40% de todas as mulheres com alto risco relataram receber aconselhamento genético para ajudá-las a decidir ou entender os resultados. Das que foram testadas, 60% receberam aconselhamento.

Reshma Jagsi, pesquisadora sênior no estudo, afirmou que os resultados são preocupantes porque os testes podem ser uma ferramenta poderosa para mulheres de grupos de risco. Ela afirmou que isso poderia afetar o tipo de cirurgia que a mulher pode optar para tratar um câncer de mama ou tratamentos para tentar diminuir o risco de desenvolver novos cânceres no futuro. Kurian disse que é como se alguns médicos não enxergassem os benefícios dos testes ou não soubessem como explicar isto para suas pacientes.

O ESTUDO

Genetic Testing and Counseling Among Patients With Newly Diagnosed Breast Cancer

Allison W. Kurian, MD, MSc1Kent A. Griffith, MS2Ann S. Hamilton, PhD3; et alKevin C. Ward, PhD, MPH4;Monica Morrow, MD5;Steven J. Katz, MD, MPH6;Reshma Jagsi, MD, DPhil7

Author Affiliations Article Information

JAMA. 2017;317(5):531-534. doi:10.1001/jama.2016.16918

Germline genetic testing of patients with breast cancer is an important model of how increasingly widespread genomic sequencing can influence treatment decision making. Testing of 2 breast cancer–associated genes, BRCA1 and BRCA2, has been available for 20 years, but new massively parallel sequencing technology and less restrictive patent laws have made multiplex panel tests available at much lower costs.1 Yet little is known about recent patient experience with genetic testing and counseling. Genetic counselors are experts in risk assessment and communication, but because of workforce limitations, some physicians must counsel and test patients without their assistance.2 These challenges motivated this investigation of patients’ use of and perspectives on genetic counseling and testing.

Methods

The study was approved by the University of Michigan institutional review board, which waived the requirement for patient consent. Women aged 20 through 79 years, diagnosed with stages 0 to II breast cancer between July 2013 and September 2014, identified by Surveillance Epidemiology and End Results registries of Georgia and Los Angeles County, were mailed surveys (Supplement) 2 months after surgical operation. Survey questions addressed how much patients wanted genetic testing (not at all, a little bit, somewhat, quite a bit, very much: the latter 4 were defined as wanting testing); and whether patients talked about testing with any “doctor or other health professional,” had a session with a genetic counseling expert, or had testing. Cancer family history, ancestry, and clinical information were used to construct a guideline-concordant measure of high pretest risk for mutation carriage.3 A log-linear model was constructed using SAS (SAS Institute), version 9.4, to compute risk ratios, adjusting for covariates (listed in Table 1) and weighted for survey design and nonresponse to identify variables independently associated with failure to receive testing among high-risk patients.

Results

A total of 2529 women (71%) responded to the survey. The mean age was 62 years (SD, 11); 56.8% were white, 17.8% black, and 71.2% had some college education (Table 1). Sixty-six percent (95% CI, 64.2%-68.2%) reported wanting testing and 29.0% (95% CI, 27.1%-30.9%) reported having a test. Thirty-one percent (n = 773; 95% CI, 29.2%-33.1%) of patients had a high pretest mutation risk. Among average-risk patients, 59.3% (95% CI, 56.8%-61.8%) wanted testing, 35.9% (95% CI, 33.4%-38.3%) reported talking about testing with a doctor or other health professional, and 17.8% (95% CI, 16.0%-19.9%) had testing (Table 2). Among high-risk patients, 80.9% (95% CI, 78.0%-83.9%) wanted testing, 70.9% (95% CI, 67.5%-74.3%) talked about testing with a doctor or other health professional, 39.6% (95% CI, 35.9%-43.3%) had a session with a genetic counseling expert, and 52.9% (95% CI, 49.1%-56.6%) had testing. Of tested high-risk patients, 61.7% (95% CI, 56.6%-66.7%) had an expert genetic counseling session. The most common reason high-risk patients reported for not testing was “my doctor didn’t recommend it” (56.1%), “too expensive” (13.7%), “I did not want it” (10.7%), and “my family didn’t want me to get it” (0.2%). On multivariable analysis (Table 1), characteristics associated with no testing included older age and Asian ethnicity but not education, income, or insurance.

Discussion

In this large, population-based study, most patients reported wanting genetic testing and 29% reported having it. Yet only 39.6% of all high-risk women and 61.7% of tested high-risk women reported having a genetic counseling session. This suggests a gap between need and availability of genetic counseling. Only 52.9% of high-risk patients had a genetic test, representing a missed opportunity to prevent ovarian and other cancer deaths among mutation carriers and their families. High-risk patients most vulnerable to undertesting included Asians and older women, despite evidence that many such patients carry mutations.4,5

Clinical need for genetic testing may not be adequately recognized by physicians. High-risk patients reported lack of a physician’s recommendation, not expense, as their primary reason for not testing. Limitations of the study included the testing data source being by patient self-report and that the patients lived in only 2 geographic regions. The findings emphasize the importance of cancer physicians in the genetic testing process. Priorities include improving physicians’ communication skills and assessments of patients’ risk and desire for testing, and optimizing triage to genetic counselors.

Section Editor: Jody W. Zylke, MD, Deputy Editor.

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AVISO IMPORTANTE
O conteúdo deste site tem o intuito de apenas informar aqueles que têm dúvidas genéricas sobre o câncer de mama. Para a análise de um caso clínico particular, como tratamento, prognóstico e outras dúvidas deve ser consultado um médico especialista.