Role of the Genetic Counselor in Familial Cancer

February 1, 1996
Katherine A. Schneider, MPH
Katherine A. Schneider, MPH

Volume 10, Issue 2

The authors offer a comprehensive overview of familial cancer risk counseling, providing both a general definition of this new genetic counseling specialty and specific components of the counseling process. Genetic counseling is, by and large, a referral service, and this is also true of cancer risk counseling. This places great importance on the health-care provider's ability to recognize families who may be at increased risk for an inherited form of cancer and should be referred for cancer risk counseling. It seems reasonable, therefore, to consider the issues relevant to making such a referral, including information on collecting an initial cancer history, strategies for handling a positive history, and the realities of DNA-based testing.

The authors offer a comprehensive overview of familial cancerrisk counseling, providing both a general definition of this newgenetic counseling specialty and specific components of the counselingprocess. Genetic counseling is, by and large, a referral service,and this is also true of cancer risk counseling. This places greatimportance on the health-care provider's ability to recognizefamilies who may be at increased risk for an inherited form ofcancer and should be referred for cancer risk counseling. It seemsreasonable, therefore, to consider the issues relevant to makingsuch a referral, including information on collecting an initialcancer history, strategies for handling a positive history, andthe realities of DNA-based testing.

Collecting an Initial Cancer History

Obtaining an extensive family history of cancer is a key elementin cancer risk counseling. However, taking an initial cancer historyis equally important, as it provides the rationale for makingthe referral in the first place. Given the increasing optionsfor DNA testing and surveillance available to individuals withknown heritable cancer risks, health-care providers of cancerpatients and their families should consider collecting initialfamily histories on a routine basis.

It is not uncommon for family histories to include one or morerelatives who have been diagnosed with cancer. Yet only a subsetof these families need to be referred to a cancer risk counselor.It is estimated that about 15% of total cancer cases are due tothe presence of a germ-line mutation in a cancer susceptibilitygene.

To help determine whether cancer risk counseling is warranted,clinicians should collect the following
information:

  • The number of relatives affected with cancer, including theexact relationship of these relatives to the patient. (Patientsmay not recognize that multiple affected cases provide evidencefor a familial cancer syndrome only if occurring in the same bloodline.)
  • The specifics of each cancer diagnosis, particularly the siteof origin and age of onset.

As stated in the article by Peters and Stopfer, it should be possibleto elicit the above information by asking patients (or parents,if the patients are minors) a few simple questions. Patients canalso be asked to check with relatives for verification of thecancer diagnoses and ages of onset. An alternative strategy wouldbe to develop a brief cancer history questionnaire for patientsto complete (either during their appointment or afterwards), whichcould then be reviewed and acted upon by clinic personnel.

Cancer histories suggestive of hereditary forms of cancer arelikely to include at least some of the following features: twoor more generations diagnosed with the same or related forms ofcancer; cancers occurring at earlier than typical ages; the presenceof rare tumors; and the presence of bilateral, multifocal, ormultiple primary tumors in one or more family members [1].

Occasionally, the pattern of cancer within a family provides unequivocalevidence of a heritable factor. In general, however, cancer historiestend to be more difficult to interpret and require further documentation.

Strategies for Handling a Positive History

Initial family histories that reveal striking incidences of cancercan be handled in one of two ways: The health-care provider maychoose to refer the patient to a center that offers familial cancerrisk counseling or may prefer to continue working directly withthe family.

The most difficult aspect of referring individuals for cancerrisk counseling may be locating such a service. Questions aboutwhere to refer patients can be directed to the Genetics Divisionwithin one's hospital, the American Cancer Society, or the NationalSociety of Genetic Counselors.

A cancer risk counselor can be a masters-level genetic counselor,an advanced practice oncology nurse, or another health-care professional.However, the number of professionals with training and experiencein this area remains limited. For example, at present fewer than100 masters-level genetic counselors specialize in cancer riskcounseling. Some hospitals are meeting patient demands for detailedcancer risk and management information by setting up specialtyclinics for individuals at increased risk for specific forms ofcancer (most often, breast, colon, or ovarian cancer). At a clinicappointment, individuals may have the opportunity to meet witha team of health-care providers to discuss issues related to theirincreased cancer risks.

The further documentation of a family with a possible inheritedform of cancer typically involves expanding the pedigree to fouror more generations. Gathering this information usually requiresdiscussions with multiple family members and the written documentationof as many cancer diagnoses as possible. These steps are critical,because the identification of a hereditary cancer syndrome maybe based solely on the cancer history, and unfortunately, cancerhistory information provided by patients is notoriously inaccurate.Because documenting cancer diagnoses can be a daunting task, itis becoming standard practice to enlist motivated family membersin these efforts. In fact, with the development of the 1993 Officefor Protection from Research Risks (OPRR) guidelines protectingpatient confidentiality, it is often easier for family membersthan for researchers to obtain this information [2].

Realities of DNA Testing

The availability of DNA testing for certain cancer susceptibilitygenes is seen as a motivating factor for patients to seek cancerrisk counseling and the primary reason for the anticipated increasein demand. Prior to undergoing predisposition testing for a cancersusceptibility gene, it is important for patients to have realisticexpectations of the testing process and to have considered thepotential ramifications of learning their test results.

Only a handful of cancer susceptibility genes have been identifiedto date, and most of them are for rare cancer syndromes. Thus,DNA testing is only available to a limited number of familieswith positive cancer histories. In addition, there needs to beat least one living family member who has been diagnosed withcancer (or several members, if testing is to be accomplished viaDNA linkage analysis), as it is necessary to document the presenceof a germ-line mutation in the family. Although DNA analysis canbe performed on tissue blocks, this method is more difficult,and most laboratories prefer working with blood specimens.

In addition, the search for a germ-line mutation in a cancer susceptibilitygene is a labor-intensive, time-consuming project that can takeseveral months. Patients need to be aware that the testing process,especially if performed on a research basis, may not be completedin a timely manner and, in fact, may not yield any results. Amongfamilies who have patterns of cancer consistent with a known cancersusceptibility gene, a certain percentage will not have identifiablemutations.

In addition to the laboratory issues, there are concerns aboutthe potential harm of releasing this information to patients.Could a genetic testing result, if positive, be used to discriminateagainst the person in matters of health or life insurance, orin employment or educational situations? Sadly, discriminationon the basis of DNA results has been reported for other geneticdiseases [3], and given society's fear of cancer, it is doubtfulthat the presence of a cancer-predisposing gene would be any lessstigmatizing. There are also concerns that knowledge of one'sgene status could engender depression and negatively influencefamily relationships and self-esteem. It is important for patientsto be aware of these potential problems prior to initiating testing.

Until there is greater experience in providing DNA predispositiontesting, such testing should be performed within a program thatincludes genetic education, informed consent, and psychologicalcounseling. Thus, the need for experienced familial cancer riskcounselors will only increase as DNA-testing options expand.

References:

1. Schneider KA: Counseling about Cancer: Strategies for GeneticCounselors, 1994.

2. National Institute of Health, Office of Extramural Research,Office for Protection from Research Risks: Protecting Human ResearchSubjects: Institutional Review Board Guidebook, 1993.

3. Billings PR, Kohn MA, de Cuevas M, et al: Discrimination asa consequence of genetic testing. Am J Hum Genet 50:476-482, 1992.