Introduction

[Note: Many of the medical and scientific terms used in this summary are found in the NCI Dictionary of Genetics Terms. When a linked term is clicked, the definition will appear in a separate window.]

[Note: A concerted effort is being made within the genetics community to shift terminology used to describe genetic variation. The shift is to use the term variant rather than the term mutation to describe a difference that exists between the person or group being studied and the reference sequence. Variants can then be further classified as benign (harmless), likely benign, of uncertain significance, likely pathogenic, or pathogenic (disease causing). Throughout this summary, we will use the term pathogenic variant to describe a disease-causing mutation. Refer to the Cancer Genetics Overview summary for more information about variant classification.]

This summary describes current approaches to assessing and counseling people about their chance of having an inherited susceptibility to cancer. Genetic counseling is defined by the National Society of Genetic Counselors as the process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease. Several reviews present overviews of the cancer risk assessment, counseling, and genetic testing process.[1,2]

Individuals are considered to be candidates for cancer risk assessment if they have a personal and/or family history (maternal or paternal lineage) with features suggestive of hereditary cancer.[1] These features vary by type of cancer and specific hereditary syndrome. Criteria have been published to help identify individuals who may benefit from genetic counseling.[1,3] The PDQ cancer genetics information summaries on breast, ovarian, endometrial, colorectal, prostate, kidney, and skin cancers and endocrine and neuroendocrine neoplasias describe the clinical features of hereditary syndromes associated with these conditions.

The following are features that suggest hereditary cancer:

As part of the process of genetic education and counseling, genetic testing may be considered when the following factors are present:

It is important that individuals who are candidates for genetic testing undergo genetic education and counseling before testing to facilitate informed decision making and adaptation to the risk or condition.[1] Genetic education and counseling allows individuals to consider the various medical uncertainties, diagnosis, or medical management based on varied test results, and the risks, benefits, and limitations of genetic testing.

Comprehensive cancer risk assessment is a consultative service that includes clinical assessment, genetic testing when appropriate, and risk management recommendations delivered in the context of one or more genetic counseling sessions. Pretest genetic counseling is an important part of the risk assessment process and helps patients understand their genetic testing options and potential outcomes. Posttest genetic counseling helps patients understand their test results, including the medical implications for themselves and their relatives.

Several professional organizations emphasize the importance of genetic counseling in the cancer risk assessment and genetic testing process. Examples of these organizations include the following:

A list of organizations that have published clinical practices guidelines related to genetic counseling, risk assessment, genetic testing, and/or management for hereditary breast and ovarian cancers is available in the PDQ summary on Genetics of Breast and Gynecologic Cancers.

Genetic counseling informs the consultand about potential cancer risks and the benefits and limitations of genetic testing and offers an opportunity to consider the potential medical, psychological, familial, and social implications of genetic information.[8,15] Descriptions of genetic counseling and the specialized practice of cancer risk assessment counseling are detailed below.

Genetic counseling has been defined by the American Society of Human Genetics as a communication process that deals with the human problems associated with the occurrence, or risk of occurrence, of a genetic disorder in a family." The process involves an attempt by one or more appropriately trained persons to help the individual or family do the following:

In 2006, the National Society of Genetic Counselors further refined the definition of genetic counseling to include the process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease, including integration of the following:

Central to the philosophy and practice of genetic counseling are the principles of voluntary utilization of services, informed decision making, attention to psychosocial and affective dimensions of coping with genetic risk, and protection of patient confidentiality and privacy. This is facilitated through a combination of rapport building and information gathering; establishing or verifying diagnoses; risk assessment and calculation of quantitative occurrence/recurrence risks; education and informed consent processes; psychosocial assessment, support, and counseling appropriate to a familys culture and ethnicity; and other relevant background characteristics.[17,18] The psychosocial assessment is especially important in the genetic counseling process because individuals most vulnerable to adverse effects of genetic information may include those who have had difficulty dealing with stressful life events in the past.[19] Variables that may influence psychosocial adjustment to genetic information include individual and familial factors; cultural factors; and health system factors such as the type of test, disease status, and risk information.[19] Findings from a psychosocial assessment can be used to help guide the direction of the counseling session.[9] An important objective of genetic counseling is to provide an opportunity for shared decision making when the medical benefits of one course of action are not demonstrated to be superior to another. The relationship between the availability of effective medical treatment for carriers of pathogenic variants and the clinical validity of a given test affects the degree to which personal choice or physician recommendation is supported in counseling at-risk individuals.[20] Uptake of genetic counseling services among those referred varies based on the cancer syndrome and the clinical setting. Efforts to decrease barriers to service utilization are ongoing (e.g., a patient navigator telephone call may increase utilization of these services).[21] Readers interested in the nature and history of genetic counseling are referred to a number of comprehensive reviews.[22-27]

Cancer risk assessment counseling has emerged as a specialized practice that requires knowledge of genetics, oncology, and individual and family counseling skills that may be provided by health care providers with this interdisciplinary training.[28] Some centers providing cancer risk assessment services involve a multidisciplinary team, which may include a genetic counselor; a genetics advanced practice nurse; a medical geneticist or a physician, such as an oncologist, surgeon, or internist; and a mental health professional. The Cancer Genetics Services Directory provides a partial list of individuals involved in cancer risk assessment, genetic counseling, testing, and other related services and is available on the National Cancer Institute's website.

The need for advanced professional training in cancer genetics for genetics counselors, physicians, nurses, laboratory technicians, and others has been widely reported.[29-32] Despite these identified needs, the evidence indicates that competency in genetics and genomics remains limited across all health care disciplines, with the exception of genetic specialists.[33] Deficits in the following have been identified: (1) knowledge about hereditary cancer syndromes [34] and risk-appropriate management strategies;[35] (2) provision of genetic counseling services;[35] (3) documentation and use of personal and family cancer history to identify and refer patients at increased risk of hereditary cancer syndromes;[36-39] and (4) knowledge about genetic nondiscrimination laws.[36,40] (Refer to the table on Health Professional Practice and Genetic Education Information in the PDQ Cancer Genetics Overview summary for more information.)

The National Coalition for Health Professional Education in Genetics (whose work was transitioned to The Jackson Laboratory in 2013) has published core competencies for all health professionals. Building on this work, individual health professions, such as physicians,[32] nurses,[41,42] physician assistants,[43] pharmacists,[44] and genetic counselors,[45] have developed and published core competencies specific to their profession. A number of other organizations have also published professional guidelines, scopes, and standards of practice.

Traditionally, genetic counseling services have been delivered using individualized in-person appointments. However, other methodologies are being explored, including group sessions, telephone counseling, and telemedicine by videoconferencing.[46-53] Additionally, computer programs and websites designed to provide genetics education can be successful adjuncts to personal genetic counseling services in a computer-literate population.[54-58]

Some studies of patient satisfaction with cancer genetic counseling services have been published. For example, one survey of individuals who participated in a cancer genetics program in its inaugural year reported that the clinical services met the needs and expectations of most people.[59] Patients reported that the best parts of the experience were simply having a chance to talk to someone about cancer concerns, having personalized summary letters and family pedigrees, learning that cancer risk was lower than expected, or realizing that one had been justified in suspecting the inheritance of cancer in ones family.

Several studies have since shown that the majority of individuals are satisfied with their genetic counseling experience.[60-63] However, one study of 61 women participating in a BRCA1/2 genetic testing program found that satisfaction with genetic counseling was influenced by psychological variables including optimism, family functioning, and general and cancer-specific distress.[64]

A meta-analysis of several controlled studies showed that outcomes of genetic counseling included improvement in cancer genetic knowledge (pooled short-term difference, 0.70 U; 95% confidence interval, 0.151.26 U). Overall, no long-term increases in general anxiety, cancer-specific worry, distress, or depression were detected as a consequence of genetic counseling. However, the impact of genetic counseling on risk perception is less clear, with some studies reporting no change in risk perception while others report significant differences before and after counseling.[65]

This section provides an overview of critical elements in the cancer risk assessment process.

A number of professional guidelines on the elements of cancer genetics risk assessment and counseling are available.[1-4] Except where noted, the discussion below is based on these guidelines.

The cancer risk assessment and counseling process, which may vary among providers, requires one or more consultative sessions and generally includes the following:

At the outset of the initial counseling session, eliciting and addressing the consultand's perceptions and concerns about cancer and his or her expectations of the risk assessment process helps to engage the consultand in the session. This also helps inform the provider about practical or psychosocial issues and guides the focus of counseling and strategies for risk assessment.

The counseling process that takes place as part of a cancer risk assessment can identify factors that contribute to the consultand's perception of cancer risk and motivations to seek cancer risk assessment and genetic testing. It can also identify potential psychological issues that may need to be addressed during or beyond the session. Information collected before and/or during the session may include the following:

Either alone or in consultation with a mental health provider, health care providers offering cancer risk counseling attempt to assess whether the individual's expectations of counseling are realistic and whether there are factors suggesting risk of adverse psychological outcomes after disclosure of risk and/or genetic status. In some cases, referral for psychotherapeutic treatment may be recommended prior to, or in lieu of, testing.[5]

Concepts of personal cancer risk, genetics, and the relationship between the two can be complex and can be difficult for patients to understand. A number of factors influence a persons concept of his or her risk, which may not be congruent with evidence-based quantitative calculations. These factors include:

A thorough understanding of these issues can greatly inform genetic education and counseling. These factors influence the processing of risk information and subsequent health behaviors.[9]

The communication of risk involves the delivery of quantitative information regarding what the data indicate about the likelihood of developing illness given various preventive actions. More broadly, however, risk communication is an interactive process regarding the individuals knowledge, beliefs, emotions, and behaviors associated with risk and the risk message conveyed. Accordingly, the goal of risk communication may be to impact the individuals knowledge of risk factors, risk likelihoods, potential consequences of risk, and the benefits and drawbacks of preventive actions.

Even before the provision of risk information, the provider may anticipate that the individual already has some sense of his or her own risk of cancer. The individual may have derived this information from multiple sources, including physicians, family members, and the media.[10] This information may be more salient or emotional if a family member has recently died from cancer or if there is a new family diagnosis.[11,12] Additionally, individuals may have beliefs about how genetic susceptibility works in their family.[13,14] For example, in a family where only females have been affected with an autosomal dominant cancer susceptibility syndrome thus far, it may be difficult to convince the consultand that her sons have a 50% risk of inheriting the disease-related pathogenic variant. The social-ecological context through which risk beliefs develop and are maintained are important as potential moderators of individuals receptivity to the cancer risk communication process and also represent the context in which individuals will return to continue ongoing decision making about how to manage their risk.[15,16] As such, individuals beliefs, and the social context of risk, are important to discuss in education and genetic risk counseling.

Perceived risk can play an important role in an individuals decision to participate in counseling,[17] despite the fact that perceived risk often varies substantially from statistical risk estimates.[18-20]

Consideration of the consultand's personal health history is essential in cancer risk assessment, regardless of whether the individual has a personal history of cancer. Important information to obtain about the consultand's health history includes the following:

For consultands with a history of cancer, additional information collected includes the following:

In some cases, a physical exam is conducted by a qualified medical professional to determine whether the individual has physical findings suggestive of a hereditary cancer predisposition syndrome or to rule out evidence of an existing malignancy. For example, a medical professional may look for the sebaceous adenomas seen in Muir-Torre syndrome, measure the head circumference or perform a skin exam to rule out benign cutaneous features associated with Cowden syndrome, or perform a clinical breast and axillary lymph node exam on a woman undergoing a breast cancer risk assessment.

The family history is an essential tool for cancer risk assessment. The family history can be obtained via interview or written self-report; both were found to result in equivalent information in a study that utilized a sample (N = 104) that varied widely in educational attainment.[22] A nine-question family history screening tool has been shown to identify individuals at increased risk of common health conditions, including cancer, who warrant a more detailed family history (receiver operating characteristic, 84.6% [range, 81.2%88.1%]; sensitivity, 95% [range, 92%98%]; specificity, 54% [range, 48%60%]).[23] Studies suggest that paper-based family history questionnaires completed before the appointment provide accurate family history information [24] and that the use of these questionnaires is an acceptable and understandable family history collection method.[25] However, questionnaire-based assessments may lead to some underreporting of family history; therefore, a follow-up interview to confirm the reported information and to capture all relevant family history information may be required.[26] Routine chart reviews (e.g., via electronic medical records) may be worthwhile to maximize the identification of appropriate candidates for genetic counseling referral. In a single nonacademic institution, systematic chart review by a genetic counselor increased the number of referrals for genetics consultation.[27] The most significant improvement was in ovarian cancer referrals. In conjunction with other efforts to collect and review family history, the performance of routine chart reviews may help identify gaps in existing referral patterns. Additionally, collecting family history from multiple relatives in a single family has been shown to increase the number of reported family members with cancer, compared with family history information provided by a single family member.[28]

Details of the family health history are best summarized in the form of a family tree, or pedigree. The pedigree, a standardized graphic representation of family relationships, facilitates identification of patterns of disease transmission, recognition of the clinical characteristics associated with specific hereditary cancer syndromes, and determination of the best strategies and tools for risk assessment.[29,30] Factors suggesting inherited cancer risk in a family are described below.

Both multimedia-based (e.g., Internet) and print-based (e.g., family history questionnaires) tools are currently available to gather information about family history. In the United States, many are written at reading grade levels above 8th grade, which may reduce their effectiveness in gathering accurate family history information. On average, print-based tools have been found to be written at lower reading grade levels than multimedia-based tools.[31]

Standards of pedigree nomenclature have been established.[29,30] Refer to Figure 1 for common pedigree symbols.

Figure 1. Standard pedigree nomenclature. Common symbols are used to draw a pedigree (family tree). A pedigree shows relationships between family members and patterns of inheritance for certain traits and diseases.

Documentation of a family cancer history typically includes the following:

A three-generation family history includes the following:

For any relative with cancer, collect the following information:[33]

For relatives not affected with cancer, collect the following information:

The accuracy of the family history has a direct bearing on determining the differential diagnoses, selecting appropriate testing, interpreting results of the genetic tests, refining individual cancer risk estimates, and outlining screening and risk reduction recommendations. In a telephone survey of 1,019 individuals, only 6% did not know whether a first-degree relative had cancer; this increased to 8.5% for second-degree relatives.[34] However, people often have incomplete or inaccurate information about the cancer history in their family.[30,33,35-41] Patient education has been shown to improve the completeness of family history collection and may lead to more-accurate risk stratification, referrals for genetic counseling, and changes to management recommendations.[42] Confirming the primary site of cancers in the family that will affect the calculation of hereditary predisposition probabilities and/or estimation of empiric cancer risks may be important, especially if decisions about treatments such as risk-reducing surgery will be based on this family history.[37,43]

A population-based survey of 2,605 first- and second-degree relatives confirmed proband reports of cancer diagnoses and found that the accuracy of reported cancer diagnoses in relatives was low to moderate, while reports of no history of cancer were accurate.[39] Accuracy varies by cancer site and degree of relatedness.[39,44,45] Reporting of cancer family histories may be most accurate for breast cancer [39,45] and less accurate for gynecologic malignancies [39,45] and colon cancer.[39] Self-reported family histories may contain errors and, in rare instances, could be fictitious.[37,43,45] The most reliable documentation of cancer histology is the pathology report. Verification of cancers can also be made through other medical records, tumor registries, or death certificates. A U.K. study illustrates the importance of verification of the cancer family history in individuals with a family history of breast cancer (n = 2,278) and colon cancer (n = 1,184).[41] Changes in genetic risk assignment (reassignment) from baseline to final time points (e.g., low risk to high risk) warranting management changes were reported in nearly 30% of families with colorectal cancer and 20% of families with breast cancer. Verification of reported cancer diagnoses in this cohort revealed a lower overall degree of consistency between reported and confirmed diagnoses than in other studies.[37,46]

It is also important to consider limited, missing, or questionable information when reviewing a pedigree for cancer risk assessment. It is more difficult to identify features of hereditary disease in families with a truncated family structure due to loss of contact with relatives, small family size, or deaths at an early age from unrelated conditions. When there are few family members of the at-risk gender when considering a particular syndrome with primarily male or female specific disease manifestations, the family history may be difficult to assess (e.g., few female members in a family at risk of hereditary breast and ovarian cancer syndrome). In addition, information collected on risk-reducing surgical procedures, such as oophorectomy, could significantly change prior probability estimation and the constellation of cancers observed in a family.[47] Other factors to clarify and document whenever possible are adoptions, use of donor egg or sperm, consanguinity, and uncertain paternity.

Additionally, family histories are dynamic. The occurrence of additional cancers may alter the likelihood of a hereditary predisposition to cancer, and consideration of differential diagnoses or empiric cancer risk estimates may change if additional cancers arise in the family. Furthermore, changes in the cancer family history over time may alter recommendations for earlier or more intense cancer screening. A descriptive study that examined baseline and follow-up family history data from a U.S. population-based cancer registry reported that family history of breast cancer or colorectal cancer becomes increasingly relevant in early adulthood and changes significantly from age 30 years to age 50 years.[48] Therefore, it is important to advise the consultand to take note of, confirm, and report cancer diagnoses or other pertinent family health history that occurs after completion of the initial risk assessment process. This is especially important if genetic testing was not performed or was uninformative.

Finally, the process of taking the family history has a psychosocial dimension. Discussing and documenting discrete aspects of family relationships and health brings the family into the session symbolically, even when a single person is being counseled. Problems that may be encountered in eliciting a family history and constructing a pedigree include difficulty contacting relatives with whom one has little or no relationship, differing views between family members about the value of genetic information, resistance to discussion of cancer and cancer-related illness, unanticipated discovery of previously unknown medical or family information, and coercion of one relative by another regarding testing decisions. In addition, unexpected emotional distress may be experienced by the consultand in the process of gathering family history information.

After an individuals personal and family cancer histories have been collected, several factors could warrant referral to a genetics professional for evaluation of hereditary cancer susceptibility syndromes. The American College of Medical Genetics and Genomics and the National Society of Genetic Counselors have published a comprehensive set of personal and family history criteria to guide the identification of at-risk individuals and appropriate referral for cancer genetic risk consultation.[49] These practice guidelines take into account tumor types or other features and related criteria that would indicate a need for a genetics referral. The authors state that the guidelines are intended to maximize appropriate referral of at-risk individuals for cancer genetic consultation but are not meant to provide genetic testing or treatment recommendations.

Because a family history of cancer is one of the important predictors of cancer risk, analysis of the pedigree constitutes an important aspect of risk assessment. This analysis might be thought of as a series of the following questions:

The following sections relate to the way that each of these questions might be addressed:

The clues to a hereditary syndrome are based on pedigree analysis and physical findings. The index of suspicion is raised by the following:

Clinical characteristics associated with distinctive risk ranges for different cancer genetic syndromes are summarized in the second edition of the Concise Handbook of Familial Cancer Susceptibility Syndromes.[50]

Hundreds of inherited conditions are associated with an increased risk of cancer. These have been summarized in texts [51-53] and a concise review.[50] Diagnostic criteria for different hereditary syndromes incorporate different features from the list above, depending on the original purpose of defining the syndrome (e.g., for gene mapping, genotype -phenotype studies, epidemiological investigations, population screening, or clinical service). Thus, a syndrome such as Lynch syndrome (also called hereditary nonpolyposis colorectal cancer [HNPCC]) can be defined for research purposes by the Amsterdam criteria as having three related individuals with colorectal cancer, with one person being a first-degree relative of the other two; spanning two generations; and including one person who was younger than age 50 years at cancer diagnosis, better known as the 3-2-1 rule. These criteria have limitations in the clinical setting, however, in that they ignore endometrial and other extracolonic tumors known to be important features of Lynch syndrome. Revised published criteria that consider extracolonic cancers of Lynch syndrome have been subsequently developed and include the Amsterdam criteria II and the revised Bethesda guidelines.

Other factors may complicate recognition of basic inheritance patterns or represent different types of disease etiology. These factors include the following:

The mode of inheritance refers to the way that genetic traits are transmitted in the family. Mendels laws of inheritance posit that genetic factors are transmitted from parents to offspring as discrete units known as genes that are inherited independently from each other and are passed on from an older generation to the following generation. The most common forms of Mendelian inheritance are autosomal dominant, autosomal recessive, and X-linked. Non-Mendelian forms of inheritance include chromosomal, complex, and mitochondrial. Researchers have learned from cancer and other inherited diseases that even Mendelian inheritance is modified by environmental and other genetic factors and that there are variations in the ways that the laws of inheritance work.[54-56]

Most commonly, Mendelian inheritance is established by a combination of clinical diagnosis with a compatible, but not in itself conclusive, pedigree pattern.[57] Below is a list of inheritance patterns with clues to their recognition in the pedigree, followed by a list of situations that may complicate pedigree interpretation.

Autosomal dominant

Autosomal recessive

X-linked

Chromosomal

Complex

Susceptibility or resistance shows a more or less normal distribution in the population. Most people have an intermediate susceptibility, with those at the tails of the distribution curve having unusually low or unusually high susceptibility. Affected individuals are presumably those who are past a point of threshold for being affected due to their particular combination of risk factors. Outside of the few known Mendelian syndromes that predispose to a high incidence of specific cancer, most cancers are complex in etiology.

Clustering of cancer among relatives is common, but teasing out the underlying causes when there is no clear pattern is more difficult. With many common malignancies, such as lung cancer, an excess of cancers in relatives can be seen. These familial aggregations are seen as being due to combinations of exposures to known carcinogens, such as tobacco smoke, and to pathogenic variants in high penetrance genes or alterations in genes with low penetrance that affect the metabolism of the carcinogens in question.[58]

The general practitioner is likely to encounter some families with a strong genetic predisposition to cancer and the recognition of cancer susceptibility may have dramatic consequences for a given individual's health and management. Although pathogenic variants in major cancer susceptibility genes lead to recognizable Mendelian inheritance patterns, they are uncommon. Nonetheless, cancer susceptibility genes are estimated to contribute to the occurrence of organ-specific cancers from less than 1% to up to 15%.[59] Pathogenic variants in these genes confer high relative risk and high absolute risk. The attributable risk is low, however, because they are so rare.

In contrast, scientists now know of polymorphisms or alterations in deoxyribonucleic acid that are very common in the general population. Each polymorphism may confer low relative and absolute risks, but collectively they may account for high attributable risk because they are so common. Development of clinically significant disease in the presence of certain genetic polymorphisms may be highly dependent on environmental exposure to a potent carcinogen. People carrying polymorphisms associated with weak disease susceptibility may constitute a target group for whom avoidance of carcinogen exposure may be highly useful in preventing full-blown disease from occurring.

For more information about specific low-penetrance genes, please refer to the summaries on genetics of specific types of cancer.

Complex inheritance might be considered in a pedigree showing the following:

These probabilities vary by syndrome, family, gene, and pathogenic variant, with different variants in the same gene sometimes conferring different cancer risks, or the same variant being associated with different clinical manifestations in different families. These phenomena relate to issues such as penetrance and expressivity discussed elsewhere.

A positive family history may sometimes provide risk information in the absence of a specific genetically determined cancer syndrome. For example, the risk associated with having a single affected relative with breast or colorectal cancer can be estimated from data derived from epidemiologic and family studies. Examples of empiric risk estimates of this kind are provided in the PDQ summaries on Genetics of Breast and Gynecologic Cancers and Genetics of Colorectal Cancer.

The overarching goal of cancer risk assessment is to individualize cancer risk management recommendations based on personalized risk. Methods to calculate risk utilize health history information and risk factor and family history data often in combination with emerging biologic and genetic/genomic evidence to establish predictions.[60] Multiple methodologies are used to calculate risk, including statistical models, prevalence data from specific populations, penetrance data when a documented pathogenic variant has been identified in a family, Mendelian inheritance, and Bayesian analysis. All models have distinct capabilities, weaknesses, and limitations based on the methodology, sample size, and/or population used to create the model. Methods to individually quantify risk encompass two primary areas: the probability of harboring a pathogenic variant in a cancer susceptibility gene and the risk of developing a specific form of cancer.[60]

The decision to offer genetic testing for cancer susceptibility is complex and can be aided in part by objectively assessing an individual's and/or family's probability of harboring a pathogenic variant.[61] Predicting the probability of harboring a pathogenic variant in a cancer susceptibility gene can be done using several strategies, including empiric data, statistical models, population prevalence data, Mendels laws, Bayesian analysis, and specific health information, such as tumor-specific features.[61,62] All of these methods are gene specific or cancer-syndrome specific and are employed only after a thorough assessment has been completed and genetic differential diagnoses have been established.

If a gene or hereditary cancer syndrome is suspected, models specific to that disorder can be used to determine whether genetic testing may be informative. (Refer to the PDQ summaries on the Genetics of Breast and Gynecologic Cancers; Genetics of Colorectal Cancer; or the Genetics of Skin Cancer for more information about cancer syndrome-specific probability models.) The key to using specific models or prevalence data is to apply the model or statistics only in the population best suited for its use. For instance, a model or prevalence data derived from a population study of individuals older than 35 years may not accurately be applied in a population aged 35 years and younger. Care must be taken when interpreting the data obtained from various risk models because they differ with regard to what is actually being estimated. Some models estimate the risk of a pathogenic variant being present in the family; others estimate the risk of a pathogenic variant being present in the individual being counseled. Some models estimate the risk of specific cancers developing in an individual, while others estimate more than one of the data above. (Refer to NCI's Risk Prediction Models website or the disease-specific PDQ cancer genetics summaries for more information about specific cancer risk prediction and pathogenic variant probability models.) Other important considerations include critical family constructs, which can significantly impact model reliability, such as small family size or male-dominated families when the cancer risks are predominately female in origin, adoption, and early deaths from other causes.[62,63] In addition, most models provide gene and/or syndrome-specific probabilities but do not account for the possibility that the personal and/or family history of cancer may be conferred by an as-yet-unidentified cancer susceptibility gene.[64] In the absence of a documented pathogenic variant in the family, critical assessment of the personal and family history is essential in determining the usefulness and limitations of probability estimates used to aid in the decisions regarding indications for genetic testing.[61,62,64]

When a pathogenic variant has been identified in a family and a test report documents that finding, prior probabilities can be ascertained with a greater degree of reliability. In this setting, probabilities can be calculated based on the pattern of inheritance associated with the gene in which the pathogenic variant has been identified. In addition, critical to the application of Mendelian inheritance is the consideration of integrating Bayes Theorem, which incorporates other variables, such as current age, into the calculation for a more accurate posterior probability.[1,65] This is especially useful in individuals who have lived to be older than the age at which cancer is likely to develop based on the pathogenic variant identified in their family and therefore have a lower likelihood of harboring the family pathogenic variant when compared with the probability based on their relationship to the carrier in the family.

Even in the case of a documented pathogenic variant on one side of the family, careful assessment and evaluation of the individuals personal and family history of cancer is essential to rule out cancer risk or suspicion of a cancer susceptibility gene pathogenic variant on the other side of the family (maternal or paternal, as applicable).[66] Segregation of more than one pathogenic variant in a family is possible (e.g., in circumstances in which a cancer syndrome has founder pathogenic variants associated with families of particular ancestral origin).

Unlike pathogenic variant probability models that predict the likelihood that a given personal and/or family history of cancer could be associated with a pathogenic variant in a specific gene(s), other methods and models can be used to estimate the risk of developing cancer over time. Similar to pathogenic variant probability assessments, cancer risk calculations are also complex and necessitate a detailed health history and family history. In the presence of a documented pathogenic variant, cancer risk estimates can be derived from peer-reviewed penetrance data.[1] Penetrance data are constantly being refined and many genetic variants have variable penetrance because other variables may impact the absolute risk of cancer in any given patient. Modifiers of cancer risk in carriers of pathogenic variants include the variant's effect on the function of the gene/protein (e.g., variant type and position), the contributions of modifier genes, and personal and environmental factors (e.g., the impact of bilateral salpingo-oophorectomy performed for other indications in a woman who harbors a BRCA pathogenic variant).[67] When there is evidence of an inherited susceptibility to cancer but genetic testing has not been performed, analysis of the pedigree can be used to estimate cancer risk. This type of calculation uses the probability the individual harbors a genetic variant and variant-specific penetrance data to calculate cancer risk.[1]

In the absence of evidence of a hereditary cancer syndrome, several methods can be utilized to estimate cancer risk. Relative risk data from studies of specific risk factors provide ratios of observed versus expected cancers associated with a given risk factor. However, utilizing relative risk data for individualized risk assessment can have significant limitations: relative risk calculations will differ based on the type of control group and other study-associated biases, and comparability across studies can vary widely.[65] In addition, relative risks are lifetime ratios and do not provide age-specific calculations, nor can the relative risk be multiplied by population risk to provide an individual's risk estimate.[65,68]

In spite of these limitations, disease-specific cumulative risk estimates are most often employed in clinical settings. These estimates usually provide risk for a given time interval and can be anchored to cumulative risks of other health conditions in a given population (e.g., the 5-year risk by the Gail model).[65,68] Cumulative risk models have limitations that may underestimate or overestimate risk. For example, the Gail model excludes paternal family histories of breast cancer.[62] Furthermore, many of these models were constructed from data derived from predominately Caucasian populations and may have limited validity when used to estimate risk in other ethnicities.[69]

Cumulative risk estimates are best used when evidence of other underlying significant risk factors have been ruled out. Careful evaluation of an individual's personal health and family history can identify other confounding risk factors that may outweigh a risk estimate derived from a cumulative risk model. For example, a woman with a prior biopsy showing lobular carcinoma in situ (LCIS) whose mother was diagnosed with breast cancer at age 65 years has a greater lifetime risk from her history of LCIS than her cumulative lifetime risk of breast cancer based on one first-degree relative.[70,71] In this circumstance, recommendations for cancer risk management would be based on the risk associated with her LCIS. Unfortunately, there is no reliable method for combining all of an individual's relevant risk factors for an accurate absolute cancer risk estimate, nor are individual risk factors additive.

In summary, careful ascertainment and review of personal health and cancer family history are essential adjuncts to the use of prior probability models and cancer risk assessment models to assure that critical elements influencing risk calculations are considered.[61] Influencing factors include the following:

A number of investigators are developing health care provider decision support tools such as the Genetic Risk Assessment on the Internet with Decision Support (GRAIDS),[72] but at this time, clinical judgment remains a key component of any prior probability or absolute cancer risk estimation.[61]

Specific clinical programs for risk management may be offered to persons with an increased genetic risk of cancer. These programs may differ from those offered to persons of average risk in several ways: screening may be initiated at an earlier age or involve shorter screening intervals; screening strategies not in routine use, such as screening for ovarian cancer, may be offered; and interventions to reduce cancer risk, such as risk-reducing surgery, may be offered. Current recommendations are summarized in the PDQ summaries addressing the genetics of specific cancers.

The goal of genetic education and counseling is to help individuals understand their personal risk status, their options for cancer risk management, and to explore feelings regarding their personal risk status. Counseling focuses on obtaining and giving information, promoting autonomous decision making, and facilitating informed consent if genetic testing is pursued.

Optimally, education and counseling about cancer risk includes providing the following information:

When a clinically valid genetic test is available, education and counseling for genetic testing typically includes the following:

If a second session is held to disclose and interpret genetic test results, education and counseling focuses on the following:

The process of counseling may require more than one visit to address medical, genetic testing, and psychosocial support issues. Additional case-related preparation time is spent before and after the consultation sessions to obtain and review medical records, complete case documentation, seek information about differential diagnoses, identify appropriate laboratories for genetic tests, find patient support groups, research resources, and communicate with or refer to other specialists.[1]

Information about inherited risk of cancer is growing rapidly. Many of the issues discussed in a counseling session may need to be revisited as new information emerges. At the end of the counseling process, individuals are typically reminded of the possibility that future research may provide new options and/or new information on risk. Individuals may be advised to check in with the health care provider periodically to determine whether new information is sufficient to merit an additional counseling session. The obligation of health care providers to recontact individuals when new genetic testing or treatment options are available is controversial, and standards have not been established.

The usage of numerical probabilities to communicate risk may overestimate the level of risk certainty, especially when wide confidence intervals exist to the estimates or when the individual may differ in important ways from the sample on which the risk estimate was derived. Also, numbers are often inadequate for expressing gut-level or emotional aspects of risk. Finally, there are wide variations in individuals level of understanding of mathematical concepts (i.e., numeracy). For all the above reasons, conveying risk in multiple ways, both numerically and verbally, with discussion of important caveats, may be a useful strategy to increase risk comprehension. The numerical format that facilitates the best understanding is natural frequencies because frequencies include information concerning the denominator, the reference group to which the individual may refer. In general, logarithmic scales are to be avoided.[2] Additionally, important contextual risks may be included with the frequency in order to increase risk comprehension; these may include how the persons risk compares with those who do not have the risk factor in question and the risks associated with common hazards, such as being in a car accident. Additional suggestions include being consistent in risk formats (do not mix odds and percentages), using the same denominator across risk estimates, avoiding decimal points, including base rate information, and providing more explanation if the risk is less than 1%.

The communication of risk may be numerical, verbal, or visual. Use of multiple strategies may increase comprehension and retention of cancer genetic risk information.[2] Recently, use of visual risk communication strategies has increased (e.g., histograms, pie charts, and Venn diagrams). Visual depictions of risk may be very useful in avoiding problems with comprehension of numbers, but research that confirms this is lacking.[3,4] A study published in 2008 examined the use of two different visual aids to communicate breast cancer risk. Women at an increased risk of breast cancer were randomized to receive feedback via a bar graph alone or a bar graph plus a frequency diagram (i.e., highlighted human figures). Results indicate that overall, there were no differences in improved accuracy of risk perception between the two groups, but among those women who inaccurately perceived very high risk at baseline, the group receiving both visual aids showed greater improvement in accuracy.[5]

The purpose of risk counseling is to provide individuals with accurate information about their risk, help them understand and interpret their risk, assist them as they use this information to make important health care decisions, and help them make the best possible adjustment to their situation. A systematic review of 28 studies that evaluated communication interventions showed that risk communication benefits users cognitively by increasing their knowledge and understanding of risk perception and does not negatively influence affect (anxiety, cancer-related worry, and depression). Risk communication does not appear to result in a change in use of screening practices and tests. Users received the most benefit from an approach utilizing risk communication along with genetic counseling.[6,7] Perceptions of risk are affected by the manner in which risk information is presented, difficulty understanding probability and heredity,[8,9] and other psychological processes on the part of individuals and providers.[10] Risk may be communicated in many ways (e.g., with numbers, words, or graphics; alone or in relation to other risks; as the probability of having an adverse event; in relative or absolute terms; and through combinations of these methods). The way in which risk information is communicated may affect the individuals perception of the magnitude of that risk. In general, relative risk estimates (e.g., "You have a threefold increased risk of colorectal cancer") are perceived as less informative than absolute risk (e.g., "You have a 25% risk of colorectal cancer") [11] or risk information presented as a ratio (e.g., 1 in 4).[9] A strong preference for having BRCA1/2 pathogenic variant risk estimates expressed numerically is reported by women considering testing.[12] Individuals associate widely differing quantitative risks with qualitative descriptors of risk such as rare or common.[13] More research is needed on the best methods of communicating risk in order to help individuals develop an accurate understanding of their cancer risks.

Recent descriptive examination of the process of cancer genetic counseling has found that counseling sessions are predominantly focused on the biomedical teaching required to inform clients of their choices and to put genetic findings in perspective but that attention to psychosocial issues does not detract from teaching goals and may enhance satisfaction in clients undergoing counseling. For instance, one study of communication patterns in 167 pretest counseling sessions for BRCA1 found the sessions to have a predominantly biomedical and educational focus;[14] however, this approach was client focused, with the counselor and client contributing equally to the dialogue. These authors note that there was a marked diversity in counselor styles, both between counselors and within different sessions, for each counselor. The finding of a didactic style was corroborated by other researchers who examined observer-rated content checklists and videotape of 51 counseling sessions for breast cancer susceptibility.[15] Of note, genetic counselors seemed to rely on demographic information and breast cancer history to tailor genetic counseling sessions rather than clients self-reported expectations or psychosocial factors.[16] Concurrent provision of psychosocial and scientific information may be important in reducing worry in the context of counseling about cancer genetics topics.[17] An increasing appreciation of language choices may contribute to enhanced understanding and reduced anxiety levels in the session; for example, it was noted that patients may appreciate synonymic choices for the word mutation, such as altered gene.[18] Some authors have published recommendations for cultural tailoring of educational materials for the African-American population, such as a large flip chart, including the use of simple language and pictures, culturally identifiable images (e.g., spiritual symbols and tribal patterns), bright colors, and humor.[19]

Studies have examined novel channels to communicate genetic cancer risk information, deliver psychosocial support, and standardize the genetic counseling process for individuals at increased risk of cancer.[20-27] Much of this literature has attempted to make the genetic counseling session more efficient or to limit the need for the counselor to address basic genetic principles in the session to free up time for the clients personal and emotional concerns about his or her risk. For example, the receipt of genetic feedback for BRCA1/2 and mismatch repair gene testing by letter, rather than a face-to-face genetic counseling feedback session, has been investigated.[28] Other modalities include the development of patient assessments or checklists, CD-ROM programs, and interactive computer programs.

Patient assessments or checklists have been developed to facilitate coverage of important areas in the counseling session. One study assessed patients psychosocial needs before a hereditary cancer counseling session to determine the assessments effect on the session.[29] A total of 246 participants from two familial cancer clinics were randomly assigned to either an intervention arm in which the counselor received assessment results or a usual care control arm. Study results demonstrated that psychosocial concerns were discussed more frequently among intervention participants than among controls, without affecting session length. Moreover, cancer worry and psychological distress were significantly lower for intervention versus control participants 4 weeks after the counseling session.

A second study compared a feedback checklist completed by 197 women attending a high-risk breast clinic prior to the counseling session to convey prior genetic knowledge and misconceptions to aid the counselor in tailoring the session for that client.[22] The use of the feedback checklist led to gains in knowledge from the counseling session but did not reduce genetic counseling time, perhaps because the genetic counselor chose to spend time discussing topics such as psychosocial issues. Use of the checklist did decrease the time spent with the medical oncologist, however. The feedback checklist was compared to a CD-ROM that outlined basic genetic concepts and the benefits and limitations of testing and found that those viewing the CD-ROM spent less time with counselors and were less likely to choose to undergo genetic testing. The CD-ROM did not lead to increased knowledge of genetic concepts, as did use of the checklist.

A prospective study evaluated the effects of a CD-ROM decisional support aid for microsatellite instability (MSI) tumor testing in 239 colorectal cancer patients who met the revised Bethesda criteria but who did not meet the Amsterdam criteria.[30] The study also tested a theoretical model of factors influencing decisional conflict surrounding decisions to pursue MSI tumor testing. Within the study, half of the sample was randomly assigned to receive a brief description of MSI testing within the clinical encounter, and the other half was provided the CD-ROM decisional support aid in addition to the brief description. The CD-ROM and brief description intervention increased knowledge about MSI testing more than the brief description alone did. As a result, decisional conflict decreased because participants felt more prepared to make a decision about the test and had increased perceived benefits of MSI testing.

Other innovative strategies include educational materials and interactive computer technology. In one study, a 13-page color communication aid using a diverse format for conveying risk, including graphic representations and verbal descriptions, was developed.[23] The authors evaluated the influence of the communication aid in 27 women at high risk of a BRCA1/2 pathogenic variant and compared those who had read the aid to a comparison sample of 107 women who received standard genetic counseling. Improvements in genetic knowledge and accuracy of risk perception were documented in those who had read the aid, with no differences in anxiety or depression between groups. Personalized, interactive electronic materials have also been developed to aid in genetic education and counseling.[24,25] In one study, an interactive computer education program available prior to the genetic counseling session was compared with genetic counseling alone in women undergoing counseling for BRCA1/2 testing.[25] Use of the computer program prior to genetic counseling reduced face-time with the genetic counselor, particularly for those at lower risk of a BRCA1/2 pathogenic variant. Many of the counselors reported that their clients use of the computer program allowed them to be more efficient and to reallocate time spent in the sessions to clients unique concerns.

Videoconferencing is an innovative strategy to facilitate genetic counseling sessions with clients who cannot travel to specialized clinic settings. In 37 individuals in the United Kingdom, real-time video conferencing was compared with face-to-face counseling sessions; both methods were found to improve knowledge and reduce anxiety levels.[26] Similarly, teleconferencing sessions, in which the client and genetic specialists were able to talk with each other in real time, were used in rural Maine communities [27] in the pediatric context to convey genetic information and findings for developmental delays and were found to be comparable to in-person consultations in terms of decision-making confidence and satisfaction with the consultations. An Australian study compared the experiences of 106 women who received hereditary breast and ovarian cancer genetic counseling via videoconferencing with the experiences of 89 women who received counseling face to face. Pre- and 1-month postcounseling assessments revealed no significant differences in knowledge gains, satisfaction, cancer-specific anxiety, generalized anxiety, depression, and perceived empathy of the genetic counselor.[31]

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Cancer Genetics Risk Assessment and Counseling (PDQ ...

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