April - June 2014 - Genetics

By:  Suzanne M. Mahon, RN, DNSc, AOCN®, APNG
Hereditary Cancer Program at Saint Louis University Cancer Center, St. Louis, MO

Q: When assessing patients in my practice, what would be indications of hereditary risk for developing breast cancer?

A: Many patients and healthcare professionals incorrectly assume that hereditary risk for breast cancer is only associated with a mutation in the BRCA1 or BRCA2. There are actually many other less common genes associated with hereditary breast cancer. These include TM, BARD1, BLM, BRIP1, CDH1, CHEK2, EPCAM, FAM175, FANCC, HOXB13, MLH1, MRE11A, MSH2, MSH6, NBN, PALB2, PMS2, PTEN, RAD50, RAD51C, RAD51D, STK11, and TP53.1,2 Recently many of these genetic tests have become commercially available through a type of testing known as next generation sequencing (NGS), which has led to reduced cost and turnaround time with the simultaneous testing of multiple genes.3,4 

Key indicators of hereditary breast cancer include:

  • Cancer in 2 or more close relatives (on same side of family)
  • Early age at diagnosis (especially breast cancer under the age of 50)
  • Multiple primary tumors (eg, two breast cancer or breast and pancreatic or ovarian cancer)
  • Bilateral or multiple rare cancers
  • Male breast cancer
  • A history of breast cancer in an individual of Ashkenazi Jewish ancestry
  • Constellation of tumors consistent with specific cancer syndrome in a family (eg, breast and ovary)
  • Evidence of autosomal dominant transmission
  • Triple negative breast cancer
  • The patient is extremely worried about the family history and risk to other family members

Deciding which test to order can be a complex process. The American College of Medical Genetics and Genomics issued a policy statement on the use of NGS that emphasized the importance of correctly identifying families likely to benefit from testing, comprehensive pretest counseling, post-test considerations, and the role of genetics professionals.5 For this reason, it is probably best to refer to a genetics professional. All nurses need to be able to identify patients and families at risk, know how to refer them to a genetics professional, and anticipate that they will help support families as they manage hereditary risk.6-10

Q: see patient who think might have hereditary risk for developing cancer. There are many cases of breast and other cancers in her family. Where should suggest she obtain more information about hereditary risk for developing cancer?

A: Identifying families at risk for genetic predisposition is a responsibility for healthcare professionals. When an assessment suggests a family at risk, it is important to begin discussing how genetic risk assessment might be beneficial for both the patient and many other family members. Often patients and families are very worried about genetic risk. Acknowledging this risk, even though it is potentially sensitive and emotionally charged information, can be very important. Sometimes this discussion can be opened by saying something such as, “Many women with a family history of cancer worry about their families—has that been a concern for you?” An open question like this often paves the way for a bigger discussion followed by information about local resources that can provide more information about genetic testing.

Many professional organizations advocate that, prior to genetic testing, appropriate patient education and counseling must be available, and that credentialed genetic professionals are best suited to provide it.8,11,12 There are three different types of credentialed genetics professionals: 

    1. Geneticists are physicians with board certification in genetics from the American Board of Medical Genetics (www.abmg.org). 
    2. Licensed genetics counselors are healthcare professionals with specialized graduate degrees in the areas of medical genetics and counseling. The American Board of Genetic Counseling certifies genetic counselors. The National Society of Genetic Counselors maintains an active website where health care professionals and the public can identify credentialed genetics professionals by zip code (www.nsgc.org). 
    3. Credentialed genetic nurses have specialized education and training in genetics and are credentialed by the Genetic Nursing Certification Commission (GNCC) after evaluation of a portfolio. Those prepared with a master’s degree in nursing who complete specialized education and training may qualify for the advanced practice nurse in genetics credential (APNG) following submission of an acceptable portfolio (www.geneticnurse.org; www.isong.org). 

Nurses often face pressure to order genetic testing, but they should carefully consider the liabilities and responsibilities associated with genetic testing. Three common errors that occur when nongenetics professionals are involved in genetic testing include (a) the wrong genetic test being ordered, (b) genetic test results being misinterpreted, and (c) inappropriate or inadequate genetic counseling, resulting in psychosocial distress or other negative outcomes.13,14 Furthermore, when genetic testing occurs without the benefit of a credentialed genetics professional, there is a very real concern that care will not be coordinated for the rest of the family potentially at risk for the genetic syndrome. Genetics professionals have the training and skills to provide such comprehensive care for families.15,16 For these reasons, it is best to try to refer a patient with a potential genetic risk for developing cancer to a credentialed genetics professional.

Q: My patient told me that she is thinking about doing genetic testing over the internet. Is there anything should share with my patient about this?

A: Direct to consumer (DTC) genetic testing includes tests that are marketed directly to the individual and can be performed without the inclusion of a physician, genetics professional, pre- and post-test counseling, coordination of care for other family members, or an insurance company.17 The patient orders the test online, pays by credit card, receives a test kit, sends a saliva sample, and when the results are ready, logs into a secure web account and obtains the results of testing. Many of these tests reportedly can assess for future risk of multiple diseases, some of which have defined management strategies and others that do not. DTC typically involves analyzing hundreds to thousands of single nucleotide polymorphism (SNP) chips to simultaneously examine thousands of small changes found across the genome. Some of these SNPs are known to be associated with a disease, although the exact clinical implications, penetrance, and disease risk conferred by many of these SNPs are unclear. Laboratories that perform clinical genetic testing must be certified by the Clinical Laboratory Improvement Amendments (CLIA) of 1988. However, many of the laboratories offering DTC testing do not disclose their CLIA certification. Several professional organizations have issued position statements warning about the risks of DTC.18-25 In general, all of these position statements express concerns that patients may not understand the impact of genetic testing results, be unprepared for the test results, be uninformed of the recommended screening or follow-up based on the results, or experience significant psychosocial distress when genetic testing occurs without informed pre- and post-test genetic counseling. This testing typically does not involve comprehensive testing for hereditary cancer syndromes. If a patient is concerned about genetic risk for developing cancer, they should undergo formal genetic counseling which includes pedigree construction, risk assessment, and counseling about the strengths, limitations, and risks of genetic testing.

mahonsm [at] slu.edu


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