The use of genetic testing in hereditary colorectal cancer syndromes: genetic testing in HNPCC, (A)FAP and MAP

Cascade genetic testing for hereditary cancer syndromes: a review of barriers and breakthroughs

Germline genetic sequencing is now at the forefront of cancer treatment and preventative medicine. Cascade genetic testing, or the testing of at-risk relatives, is extremely promising as it offers genetic testing and potentially life-saving risk-reduction strategies to a population exponentially enriched for the risk of carrying a cancer-associated pathogenic variant. However, many relatives do not complete cascade testing due to barriers that span individual, relationship, healthcare community, and societal/policy domains. We have reviewed the published research on cascade testing. Our aim is to evaluate barriers to cascade genetic testing for hereditary cancer syndromes and explore strategies to mitigate these barriers, with the goal of promoting increased uptake of cascade genetic testing.

National Experiences from 30 Years of Provider-Mediated Cascade Testing in Lynch Syndrome Families-The Danish Model

Cascade genetic testing and surveillance reduce morbidity and mortality in Lynch syndrome. However, barriers to conveying information about genetic disorders within families result in low uptake of genetic testing. Provider-mediated interventions may increase uptake but raise legal and ethical concerns. We describe 30 years of national experience with cascade genetic testing combining family- and provider-mediated contact in Lynch syndrome families in the Danish Hereditary Non-Polyposis Colorectal Cancer (HNPCC) Register. We aimed to estimate the added value of information letters to family members in Lynch syndrome families (provider-mediated contact) compared to family members not receiving such letters and thus relying on family-mediated contact. National clinical practice for cascade genetic testing, encompassing infrastructure, legislation, acceptance, and management of the information letters, is also discussed. Cascade genetic testing resulted in 7.3 additional tests per family. Uptake of genetic testing was 54.4% after family-mediated and 64.9% after provider-mediated contact, corresponding to an odds ratio of 1.8 (p < 0.001). The uptake of genetic testing was highest in the first year after diagnosis of Lynch syndrome in the family, with 72.5% tested after provider-mediated contact. In conclusion, the Danish model combining family- and provider-mediated contact can increase the effect of cascade genetic testing.

Cascade Testing for Hereditary Cancer Syndromes: Should We Move Toward Direct Relative Contact? A Systematic Review and Meta-Analysis

PURPOSE

Evidence-based guidelines recommend cascade genetic counseling and testing for hereditary cancer syndromes, providing relatives the opportunity for early detection and prevention of cancer. The current standard is for patients to contact and encourage relatives (patient-mediated contact) to undergo counseling and testing. Direct relative contact by the medical team or testing laboratory has shown promise but is complicated by privacy laws and lack of infrastructure. We sought to compare outcomes associated with patient-mediated and direct relative contact for hereditary cancer cascade genetic counseling and testing in the first meta-analysis on this topic.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PROSPERO No.: CRD42020134276). We searched key electronic databases to identify studies evaluating hereditary cancer cascade testing. Eligible trials were subjected to meta-analysis.

RESULTS

Eighty-seven studies met inclusion criteria. Among relatives included in the meta-analysis, 48% (95% CI, 38 to 58) underwent cascade genetic counseling and 41% (95% CI, 34 to 48) cascade genetic testing. Compared with the patient-mediated approach, direct relative contact resulted in significantly higher uptake of genetic counseling for all relatives (63% [95% CI, 49 to 75] v 35% [95% CI, 24 to 48]) and genetic testing for first-degree relatives (62% [95% CI, 49 to 73] v 40% [95% CI, 32 to 48]). Methods of direct contact included telephone calls, letters, and e-mails; respective rates of genetic testing completion were 61% (95% CI, 51 to 70), 48% (95% CI, 37 to 59), and 48% (95% CI, 45 to 50).

CONCLUSION

Most relatives at risk for hereditary cancer do not undergo cascade genetic counseling and testing, forgoing potentially life-saving medical interventions. Compared with patient-mediated contact, direct relative contact increased rates of cascade genetic counseling and testing, arguing for a shift in the care delivery paradigm, to be confirmed by randomized controlled trials.

Health Economics Research in Primary Prevention of Cancer: Assessment, Current Challenges, and Future Directions

In the past 2 decades, the demand for information on health economics research to guide health care decision making has substantially increased. Studies have provided evidence that eliminating or reducing tobacco use; eating a healthy diet, including fruit and vegetables; being physically active; reducing alcohol consumption; avoiding ultraviolet radiation; and minimizing exposure to environmental and occupational carcinogenic agents should substantially reduce cancer incidence in the population. The benefits of these primary prevention measures in reducing cancer incidence are not instantaneous. Therefore, health economics research has an important role to play in providing credible information to decision makers on the health and economic benefits of primary prevention. This article provides an overview of health economics research related to primary prevention of cancer. We addressed the following questions: 1) What are the gaps and unmet needs for performing health economics research focused on primary prevention of cancer? 2) What are the challenges and opportunities to conducting health economics research to evaluate primary prevention of cancer? and 3) What are the future directions for enhancing health economics research on primary prevention of cancer? Modeling primary prevention of cancer is often difficult given data limitations, long delays before the policy or intervention is effective, possible unintended effects of the policy or intervention, and the necessity of outside expertise to understand key inputs or outputs to the modeling. Despite these challenges, health economics research has an important role to play in providing credible information to decision makers on the health and economic benefits of primary prevention of cancer.

Genetic testing in families with hereditary colorectal cancer in British Columbia and Yukon: a retrospective cross-sectional analysis

BACKGROUND

Genetic testing in families with hereditary cancer enables identification of people most likely to benefit from intensive screening and preventive measures; however, the uptake of testing in relatives (known as cascade carrier testing) for hereditary colorectal cancer syndromes has been shown to be low. Our objective was to report rates of familial testing for hereditary colorectal cancer syndromes in a publicly funded hereditary cancer clinic in Canada.

METHODS

A cross-sectional retrospective database review was used to determine testing uptake between 1997 and 2016 for families served by the provincial Hereditary Cancer Program for British Columbia and Yukon. Analyses were conducted for genes associated with syndromes with an increased risk for colorectal cancer, including Lynch syndrome (MLH1, MSH2, MSH6, PMS2 and EPCAM) and familial adenomatous polyposis (APC), and for additional moderate- to high-penetrance genes (STK11, TP53, SMAD4, MUTYH, PTEN and CHEK2). Descriptive statistics were used and all analyses were 2-tailed.

RESULTS

The study cohort included 245 index patients, with carrier testing performed in 382 relatives. The mean age at family member testing was 41.2 years, and most (61.0%) of the family members who underwent testing were women. The median time between disclosure of index cases and their family member's results was 8.3 months. Among eligible first-degree relatives, 32.6% (268/821) underwent testing in BC. Of 67 cancer diagnoses in family members, most (62.7%) occurred before genetic testing.

INTERPRETATION

A substantial proportion of people at risk for hereditary colorectal cancer do not undergo genetic testing. This gap highlights the need to explore barriers to testing and to consider interventions to promote uptake; more aggressive efforts by hereditary cancer programs are needed to reach this highest risk population.

Uptake and predictors of colonoscopy use in family members not participating in cascade genetic testing for Lynch syndrome

Cascade genetic testing provides a method to appropriately focus colonoscopy use in families with Lynch syndrome (LS). However, research suggests that up to two-thirds at risk to inherit LS don’t participate. Within the United States, no studies have assessed colonoscopy use within this elusive and high-risk subset. We set forth to (1) document colonoscopy use within those not undergoing genetic testing (NGT) and (2) identify factors associated with completing colonoscopy. Data came from a cross sectional survey of families with molecularly confirmed LS. One hundred seventy-six (176) adults participated; 47 of unknown variant status and 129 with variant status known (59 carriers/70 non-carriers). Despite a high level of awareness of LS (85%) and identical recommendations for colonoscopy, NGT reported significantly lower use of colonoscopy than carriers (47% vs. 73%; p = 0.003). Our results show that perceived risk to develop colon cancer (AOR = 1.99, p < 0.05) and physician recommendations (AOR = 7.64, p < 0.01) are significant predictors of colonoscopy use across all family members controlling for carrier status. Given these findings, health care providers, should assess patients’ perceived risk to develop cancer, assist them in adjusting risk perceptions and discuss recommendations for colonoscopy with all members in families with LS.

Trial Registration Clinical Trials.gov Identifier: NCT00004210.

Cost-effectiveness analysis of genetic diagnostic strategies for Lynch syndrome in Italy

Lynch syndrome (LS) is an autosomal dominant condition caused by pathogenic variants in mismatch repair (MMR) genes that predispose individuals to different malignancies, such as colorectal cancer (CRC) and endometrial cancer. Current guidelines recommended testing for LS in individuals with newly diagnosed CRC to reduce cancer morbidity and mortality in relatives. Economic evaluations in support of such approach, however, are not available in Italy. We developed a decision-analytic model to analyze the cost-effectiveness of LS screening from the perspective of the Italian National Health System. Three testing strategies: the sequencing of all MMR genes without prior tumor analysis (Strategy 1), a sequential IHC and MS-MLPA analysis (Strategy 2), and an age-targeted strategy with a revised Bethesda criteria assessment before IHC and methylation-specific MLPA for patients ≥ than 70 years old (Strategy 3) were analyzed and compared to the “no testing” strategy. Quality Adjusted Life Years (QALYs) in relatives after colonoscopy, aspirin prophylaxis and an intensive gynecological surveillance were estimated through a Markov model. Assuming a CRC incidence rate of 0.09% and a share of patients affected by LS equal to 2.81%, the number of detected pathogenic variants among CRC cases ranges, in a given year, between 910 and 1167 depending on the testing strategy employed. The testing strategies investigated, provided one-time to the entire eligible population (CRC patients), were associated with an overall cost ranging between €1,753,059.93-€10,388,000.00. The incremental cost-effectiveness ratios of the Markov model ranged from €941.24 /QALY to €1,681.93 /QALY, thus supporting that “universal testing” versus “no testing” is cost-effective, but not necessarily in comparison with age-targeted strategies. This is the first economic evaluation on different testing strategies for LS in Italy. The results might support the introduction of cost-effective recommendations for LS screening in Italy.

A tailored approach towards informing relatives at risk of inherited cardiac conditions: study protocol for a randomised controlled trial

INTRODUCTION

In current practice, probands are asked to inform relatives about the possibility of predictive DNA testing when a pathogenic variant causing an inherited cardiac condition (ICC) is identified. Previous research on the uptake of genetic counselling and predictive DNA testing in relatives suggests that not all relatives are sufficiently informed. We developed a randomised controlled trial to evaluate the effectiveness of a tailored approach in which probands decide together with the genetic counsellor which relatives they inform themselves and which relatives they prefer to have informed by the genetic counsellor. Here, we present the study protocol of this randomised controlled trial.

METHODS

A multicentre randomised controlled trial with parallel-group design will be conducted in which an intervention group receiving the tailored approach will be compared with a control group receiving usual care. Adult probands diagnosed with an ICC in whom a likely pathogenic or pathogenic variant is identified will be randomly assigned to the intervention or control group (total sample: n=85 probands). Primary outcomes are uptake of genetic counselling and predictive DNA testing by relatives (total sample: n=340 relatives). Secondary outcomes are appreciation of the approach used and impact on familial and psychological functioning, which will be assessed using questionnaires. Relatives who attend genetic counselling will be asked to fill out a questionnaire as well.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Medical Ethical Committee of the Amsterdam University Medical Centres (MEC 2017-145), the Netherlands. All participants will provide informed consent prior to participation in the study. Results of the study on primary and secondary outcome measures will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NTR6657; Pre-results.

The uptake of presymptomatic genetic testing in hereditary breast-ovarian cancer and Lynch syndrome: a systematic review of the literature and implications for clinical practice

Following the identification in a proband of a germline BRCA1/BRCA2 mutation in hereditary breast-ovarian cancer (HBOC) or a DNA mismatch repair gene mutation in Lynch syndrome (LS) he or she will be asked to inform at-risk family members about the option for presymptomatic DNA testing. However, in clinical practice multiple factors may complicate the process of information sharing. We critically evaluated studies on the uptake of presymptomatic genetic testing in both syndromes. A search of relevant MeSH terms and key words in PubMed, Embase and PsycINFO yielded 795 articles published between 2001 and 2017. Thirty of these publications included outcome measures relevant for the current study. Based on information provided by the proband (15 studies) the uptake of presymptomatic genetic testing ranged from 15 to 57% in HBOC, while one study in LS kindreds reported an uptake of 70%. Based on information provided by genetics centres (the remaining 15 studies) the uptake ranged from 21 to 44% in HBOC and from 41 to 94% in LS. However, when genetics centres contacted relatives directly a substantial number of additional family members could be tested. Proband-mediated provision of information to at-risk relatives is a standard procedure in hereditary breast-ovarian cancer and Lynch syndrome. However, the resulting uptake of presymptomatic testing is disappointing-an issue that is now urgent due to the increased use of genetic testing in clinical oncology. We propose that additional strategies should be introduced including the geneticist directly contacting relatives. The outcomes of these strategies should be carefully monitored and evaluated.

How to support cancer genetics counselees in informing at-risk relatives? Lessons from a randomized controlled trial

OBJECTIVE

In hereditary and familial cancer, counselees are requested to inform their at-risk relatives. We developed an intervention to support counselees in this task.

METHODS

A randomized controlled trial was conducted aimed at improving cancer genetic counselees' i) knowledge, ii) motivation to disclose information, and ii) self-efficacy in this regard. Eligible participants were randomized to telephonic counseling (n = 148), or standard care (n = 157) and assessed at baseline, 1 week post-intervention, and 4 months after study enrolment.

RESULTS

No between-group differences were found in participants' knowledge, motivation, and self-efficacy. Knowledge concerning which second-degree relatives to inform was lower compared to first-degree relatives. About 60% of the participants was of the opinion that they needed to inform more relatives than stated in their summary letter and only about 50% were correctly aware of which information to disclose. Of note, at baseline, almost 80% of the participants had already correctly informed their at-risk relatives.

CONCLUSIONS

Since, unexpectedly, counselees already informed most of their relatives before the intervention was offered, efficacy of the intervention could not convincingly be determined. Counselees' knowledge about whom to inform about what is suboptimal.

PRACTICE IMPLICATIONS

Future interventions should target a more homogeneous sample and address counselees' understanding and recall.

Uptake of genetic testing by the children of Lynch syndrome variant carriers across three generations

Many Lynch syndrome (LS) carriers remain unidentified, thus missing early cancer detection and prevention opportunities. Tested probands should inform their relatives about cancer risk and options for genetic counselling and predictive gene testing, but many fail to undergo testing. To assess predictive testing uptake and demographic factors influencing this decision in LS families, a cross-sectional registry-based cohort study utilizing the Finnish Lynch syndrome registry was undertaken. Tested LS variant probands (1184) had 2068 children divided among three generations: 660 parents and 1324 children (first), 445 and 667 (second), and 79 and 77 (third). Of children aged >18 years, 801 (67.4%), 146 (43.2%), and 5 (23.8%), respectively, were genetically tested. Together, 539 first-generation LS variant carriers had 2068 children and grandchildren (3.84 per carrier). Of the 1548 (2.87 per carrier) eligible children, 952 (61.5%) were tested (1.77 per carrier). In multivariate models, age (OR 1.08 per year; 95% CI 1.06-1.10), family gene (OR 2.83; 1.75-4.57 for MLH1 and 2.59; 1.47-4.56 for MSH2 compared with MSH6), one or more tested siblings (OR 6.60; 4.82-9.03), no siblings (OR 4.63; 2.64-8.10), and parent under endoscopic surveillance (OR 5.22; 2.41-11.31) were independent predictors of having genetic testing. Examples of parental adherence to regular surveillance and genetically tested siblings strongly influenced children at 50% risk of LS to undergo predictive gene testing. High numbers of untested, adult at-risk individuals exist even among well-established cohorts of known LS families with good adherence to endoscopic surveillance.

Germline mutations in patients with multiple colorectal polyps in China

BACKGROUND AND AIM

Multiple colorectal polyps are relevant in hereditary colorectal cancer (CRC) syndromes, which are thought to be caused by multiple events including germline mutations. This study was aimed to characterize germline mutations in Chinese patients with multiple colorectal polyps.

METHODS

Patients with > 10 colorectal polyps at the Department of Gastroenterology of the PLA Army General Hospital were enrolled from January 2014 to December 2015. These patients were divided into the high-risk, moderate-risk, and mild-risk groups. White blood cell samples were collected, and DNA was extracted to sequence a panel of 19 genes previously associated with CRC by next-generation sequencing.

RESULTS

A total of 96 patients were enrolled in the study. Pathogenic germline mutations were found in 24 (24/33, 72.73%), nine (9/24, 37.5%), and three patients (3/39, 7.7%) in the high-risk, moderate-risk, and mild-risk groups, respectively. Based on the results given, we suggested a strategy about gene sequencing test for the patients with multiple polyps, and the sensitivity and specificity of the screening strategy were 97% and 57%, respectively. Four of eight patients with MUTYH pathogenic germline mutations had the c.A934-2G monoallelic germline mutation, whereas three of eight patients had the C55T MUTYH germline mutation. Concurrent pathogenic germline mutations in APC and MUTYH were also observed.

CONCLUSIONS

A genetic screening strategy comprising 19 genes was effective to screen for hereditary CRC syndromes in patients with multiple colorectal polyps. The MUTYH germline mutation hotspots in Chinese patients may be different from those in Caucasian patients.

Facteurs génétiques à prendre en considération dans le cadre de l'examen gynécologique annuel

OBJECTIF

Offrir aux médecins un survol des troubles génétiques courants qui devraient être pris en considération dans le cadre de l'examen gynécologique annuel d'une patiente, et ce, afin de déterminer le risque que court celle-ci ou d'en venir à procéder à des examens particuliers ou à orienter la patiente vers un autre service de sous-spécialité, en fonction de ses antécédents personnels ou familiaux.

OPTIONS

Ces renseignements d'ordre génétique peuvent être utilisés aux fins de la sensibilisation des patientes et du dépistage ou du diagnostic de possibles maladies et/ou mutations.

ISSUES

L'utilisation de ces renseignements d'ordre génétique pourrait mener à l'amélioration de l'évaluation des risques et des avantages et à celle de la prise en charge dans le cadre de l'examen gynécologique annuel. RéSULTATS: Les études publiées en anglais, jusques et y compris en mai 2010, ont été récupérées par l'intermédiaire de recherches menées dans PubMed et la Cochrane Library au moyen d'un vocabulaire contrôlé (« gynaecological diagnosis », « genetic inheritance ») et de mots clés (« genetic risk », « genetic mutation », « inheritance », « family history », « uterus », « ovary », « endometrial », « vagina », « colon », « gastric », « renal », « breast », « cardiac », « thrombophilia », « diabetes », « epilepsy », « leiomyomata uteri ») appropriés. D'autres sources ont été identifiées par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales.

VALEURS

Le niveau des résultats ne permet pas la formulation de recommandations factuelles. AVANTAGES, DéSAVANTAGES ET COûTS: La présente opinion de comité améliorera l'utilisation de nouvelles connaissances génétiques et leur application aux soins gynécologiques offerts annuellement aux femmes. Les occasions de gestion du risque et de diagnostic, pour ce qui est des troubles gynécologiques génétiques, s'en trouveront améliorées. Une compréhension plus exhaustive des troubles génétiques pourrait entraîner une hausse de l'anxiété et du stress psychologique chez les femmes et les membres de leur famille.

COMMANDITAIRE

Société des obstétriciens et gynécologues du Canada.

RECOMMANDATIONS

Le niveau des résultats ne permet pas la formulation de recommandations factuelles.

Recognition of Lynch Syndrome Amongst Newly Diagnosed Colorectal Cancers at St. Paul's Hospital

BACKGROUND

Lynch Syndrome (LS) is the most common cause of inherited colorectal cancer (CRC). In British Columbia, most centres still use clinical criteria (Amsterdam II, Revised Bethesda, or the BC Cancer Agency's criteria) to determine who should undergo further first-line testing in the form of microsatellite instability or immunohistochemistry staining. Given the limitations with this strategy, LS is thought to be underrecognized.

OBJECTIVE

To investigate whether LS is truly underrecognized when compared to the reported prevalence.

METHODS

A retrospective chart review of all CRC cases diagnosed at St. Paul's Hospital from 2010 to 2013 was conducted.

RESULTS

246 patients met inclusion criteria. 76% (83/109) with a family history of malignancy were unable to recall the specific malignancy or age of diagnosis. 18% (43/235) were only asked about a history of gastrointestinal related malignancy and 26% (65/246) met at least one of the three criteria but only 21% (13/63) received further investigation. Only 1.6% (4/246) had LS compared to the reported prevalence of 2-5% of all CRC cases.

CONCLUSION

This data supports our hypothesis that LS is underrecognized. Issues at the patient, physician, and systems level need to be evaluated to determine where the limitations preventing appropriate testing are occurring.

Familial adenomatous polyposis in China

Familial adenomatous polyposis (FAP) is an autosomal dominant disease with a poor prognosis, and has been studied by clinicians and geneticists in China for the past three decades. It is estimated that FAP has an incidence of between 1 in 8,000 and 1 in 10,000 individuals, and accounts for 0.94% of colorectal cancer cases in China. Recent advances in the understanding of FAP suggest that the genotype of the patient may allow for early diagnosis and surveillance, and guide surgical and chemopreventive management. However, the genetic mechanisms of FAP vary between different countries. FAP in China has its own characteristics, and this may be due to ethnic and geographical genetic variation. In the present review the clinical manifestations and genetics of FAP in China are discussed, as well as the surgical strategies, chemotherapeutics and traditional Chinese medicines used in its treatment. Increased insight into the genetic and clinical features of FAP in the Chinese population may aid in the prevention and management of the disorder.

Genetic testing for Lynch syndrome: family communication and motivation

Current genetic counselling practice for Lynch syndrome (LS) relies on diagnosed index patients to inform their biological family about LS, referred to as the family-mediated approach. The objective of this study was to evaluate this approach and to identify factors influencing the uptake of genetic testing for LS. In 59 mutation carriers, 70 non carriers and 16 non-tested relatives socio-demographic characteristics, family communication regarding LS, experiences and attitudes towards the family-mediated approach and motivations for genetic testing, were assessed. The majority of all respondents (73 %) were satisfied with the family-mediated approach. Nevertheless, 59 % of the respondents experienced informing a family member and 57 % being informed by a family member as burdensome. Non-tested differed from tested respondents, in that they were younger, less closely related to the index patient and a lower proportion had children. The most important reasons for declining genetic testing were (1) anticipating problems with life insurance and mortgage, (2) being content with life as it is, and (3) not experiencing any physical complaints. In conclusion, the majority of respondents consider the current family-mediated information procedure acceptable, although the provision of information on LS by relatives may be burdensome. Special attention should be paid to communication of LS to more distant relatives.

SCA2 predictive testing in Cuba: challenging concepts and protocol evolution

Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease caused by a CAG repeat expansion in the ATXN2 gene. Cuba has the highest prevalence (6.57 cases/10(5) inhabitants) of SCA2 in the world. The existence of 753 affected individuals and 7173 relatives at risk prompted the development in 2001 of the first predictive testing program in the country. The medical records of over 1193 individuals, who requested the test within a 13-year period, were analyzed retrospectively. The presymptomatic and the prenatal tests had uptake rates of 43.4 and 23.9 %, respectively. Several ethical challenges resulted from this program. These include the following: (1) withdrawal due to the initial protocol's length; (2) the request to participate by 16 at-risk adolescents; (3) the decision made by ten out of 33 couples with a test-positive fetus to carry the pregnancy to term, leading to de facto predictive testing of minors; (4) the elevated frequency of the ATXN2 gene large normal alleles (≥23 to 31 repeats) in the reference population. These issues have led to major changes in the guidelines of the predictive testing protocol: (1) the protocol length was shortened; (2) the inclusion criteria were expanded to reach at-risk adolescents with an interest in prenatal diagnosis; (3) interdisciplinary follow-up was offered to families in which test-positive fetuses were not aborted; (4) prenatal testing was made available to carriers of large normal alleles with ≥27 CAG repeats. The profiles of the participants were similar to those reported for other predictive testing programs for conditions like Huntington disease and familial adenomatous polyposis. The genetic counseling practices at the community level, the ample health education provided to the at-risk population, together with multidisciplinary and specialized attention to the affected families, are lessons from the Cuban experience that can be relevant for other international teams conducting predictive testing for other late-onset neurodegenerative disorders.

History, genetics, and strategies for cancer prevention in Lynch syndrome

Colorectal cancer (CRC) is the most common gastrointestinal malignancy and the third cause of cancer death in men and women in the United States. The majority of CRC cases diagnosed annually are due to sporadic events, but up to 6% are attributed to known monogenic disorders that confer a markedly increased risk for the development of CRC and multiple extracolonic malignancies. Lynch syndrome is the most common inherited CRC syndrome and is associated with mutations in DNA mismatch repair genes, mainly MLH1 and MSH2 but also MSH6, PMS2, and EPCAM. Although the risk of CRC and endometrial cancer may approach near 75% and 50%, respectively, in gene mutation carriers, the identification of these individuals and at-risk family members through predictive genetic testing provides opportunities for cancer prevention including specialized cancer screening, intensified surveillance, and/or prophylactic surgeries. This article will provide a review of the major advances in risk assessment, molecular genetics, DNA mutational analyses, and cancer prevention and management made since Lynch syndrome was first described 100 years ago.

Informing family members of individuals with Lynch syndrome: a guideline for clinical geneticists

The diagnosis of Lynch syndrome can lead to the prevention of colorectal cancer through periodic colonoscopies and removal of premalignant lesions in susceptible individuals. Therefore, predisposed individuals identified by mutation analysis are advised to inform their at-risk relatives about the options of predictive DNA testing and preventive measures. However, it has now been established that more than half of these relatives do not receive the necessary information. Barriers in conveying information include family communication problems and variable attitudes and practice among clinical geneticists. In this complex field, both medical, psychological, ethical and juridical aspects deserve consideration. Here we summarize the development of a revised guideline for clinical geneticists that allows a more active role of the geneticist, aimed at improving procedures to inform family members in Lynch syndrome and other hereditary and familial cancer syndromes.

Addressing the ethical challenges in genetic testing and sequencing of children

American Academy of Pediatrics (AAP) and American College of Medical Genetics (ACMG) recently provided two recommendations about predictive genetic testing of children. The Clinical Sequencing Exploratory Research Consortium's Pediatrics Working Group compared these recommendations, focusing on operational and ethical issues specific to decision making for children. Content analysis of the statements addresses two issues: (1) how these recommendations characterize and analyze locus of decision making, as well as the risks and benefits of testing, and (2) whether the guidelines conflict or come to different but compatible conclusions because they consider different testing scenarios. These statements differ in ethically significant ways. AAP/ACMG analyzes risks and benefits using best interests of the child and recommends that, absent ameliorative interventions available during childhood, clinicians should generally decline to order testing. Parents authorize focused tests. ACMG analyzes risks and benefits using the interests of the child and other family members and recommends that sequencing results be examined for additional variants that can lead to ameliorative interventions, regardless of age, which laboratories should report to clinicians who should contextualize the results. Parents must accept additional analysis. The ethical arguments in these statements appear to be in tension with each other.

Uptake of genetic testing by relatives of lynch syndrome probands: a systematic review

BACKGROUND & AIMS

Screening of persons with newly diagnosed colorectal cancer for Lynch syndrome can yield substantial benefits at acceptable costs, presuming sufficient uptake of genetic testing by first-degree relatives of Lynch syndrome probands. We performed a systematic review of the literature to determine the frequency of and factors associated with genetic testing of first-degree relatives of Lynch syndrome probands.

METHODS

We searched 4 databases (CINAHL, PsycInfo, PUBMED, and SCOPUS) for articles published through May 2011 reporting uptake of genetic testing by relatives of Lynch syndrome probands. Two investigators independently screened articles to determine whether they met inclusion criteria; data were collected on study population, genetic counseling, and genetic testing. A narrative, qualitative systematic review was performed.

RESULTS

We identified 1258 potentially relevant articles; 533 underwent full-text review, and 8 were included in the final analysis. Of first-degree relatives of Lynch syndrome probands, 52% or less received genetic testing. For each proband, 3.6 or fewer relatives underwent genetic testing. Demographic factors (age <50 years, female sex, parenthood, level of education, employment, participation in medical studies), psychological factors (lack of depressive symptoms), and possibly family history (greater number of relatives with cancer) were associated with uptake of genetic testing.

CONCLUSIONS

Genetic testing appears to be underutilized by first-degree relatives of patients with Lynch syndrome. The clinical benefit and economic feasibility of screening persons with colorectal cancer for Lynch syndrome depend on optimizing family-wide uptake of genetic testing. Future research and clinical efforts should focus on ways to overcome barriers to genetic testing.

Genetic considerations for a woman's annual gynaecological examination

OBJECTIVE

To provide the physician with an overview of common genetic conditions that should be considered during a women's annual gynaecological assessment to determine the patient's risk or to initiate specific testing or referral to another subspecialty service, depending on personal or family history.

OPTIONS

This genetic information can be used for patient education and possible disease and/or mutation screening or diagnosis.

OUTCOMES

The use of this genetic information may allow improved risk-benefit assessment and management at the annual gynaecological examination.

EVIDENCE

Studies published in English up to and including May 2010 were retrieved through searches of PubMed and the Cochrane Library, using appropriate controlled vocabulary (gynaecological diagnosis, genetic inheritance) and key words (genetic risk, genetic mutation, inheritance, family history, uterus, ovary, endometrial, vagina, colon, gastric, renal, breast, cardiac, thrombophilia, diabetes, epilepsy, leiomyomata uteri). Other literature sources were identified through searching the web sites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The levels of evidence are not adequate for evidence-based recommendations to be made.

BENEFITS, HARMS, AND COSTS

This committee opinion will enhance the use of new genetic knowledge and its application to the annual gynaecological care of women. Risk management and diagnostic opportunities for genetic gynaecological conditions will be improved. A more complete understanding of genetic conditions may increase anxiety and psychological stress for women and their families.

SPONSORS

Society of Obstetricians and Gynaecologists of Canada.

RECOMMENDATIONS

The levels of evidence are not adequate for evidence-based recommendations to be made.

Colorectal cancer survivors' interest in genetic testing for hereditary cancer: implications for universal tumor screening

AIMS

Benefits of universal tumor screening for Lynch syndrome (LS), the most common form of hereditary colorectal cancer (CRC), will be realized only if patients are interested in genetic counseling and testing. This study explores interest in genetic testing for hereditary CRC among CRC patients who have never received genetic counseling or testing.

METHODS

Using results from a cross-sectional survey of CRC patients (n=91) at varying categories of risk for hereditary CRC, bivariate and multivariable analyses were conducted to compare positive and negative attitudinal beliefs regarding genetic testing, risk perceptions, demographics, and tumor stage of those who were interested in genetic testing (n=61) and those who were not interested or were not sure (n=30).

RESULTS

Although significant at the bivariate level, gender, perceived relative risk of hereditary cancer, employment status, and belief that genetic testing would help in preparing for the future were not significantly related to interest in genetic testing when controlling for all other variables in a logistic regression model. The two factors that remained significant include a single-item question measuring the belief that genetic testing is warranted based on personal/family history and a positive attitudinal scale regarding the utility of genetic testing in medical decision making and cancer prevention.

CONCLUSION

Results have potential implications for policies regarding universal tumor screening for LS.

The Genome-based Knowledge Management in Cycles model: a complex adaptive systems framework for implementation of genomic applications

The main mission of the Genomic Applications in Practice and Prevention Network™ is to advance collaborative efforts involving partners from across the public health sector to realize the promise of genomics in healthcare and disease prevention. We introduce a new framework that supports the Genomic Applications in Practice and Prevention Network mission and leverages the characteristics of the complex adaptive systems approach. We call this framework the Genome-based Knowledge Management in Cycles model (G-KNOMIC). G-KNOMIC proposes that the collaborative work of multidisciplinary teams utilizing genome-based applications will enhance translating evidence-based genomic findings by creating ongoing knowledge management cycles. Each cycle consists of knowledge synthesis, knowledge evaluation, knowledge implementation and knowledge utilization. Our framework acknowledges that all the elements in the knowledge translation process are interconnected and continuously changing. It also recognizes the importance of feedback loops, and the ability of teams to self-organize within a dynamic system. We demonstrate how this framework can be used to improve the adoption of genomic technologies into practice using two case studies of genomic uptake.

Ethical, legal and social implications of prenatal and preimplantation genetic testing for cancer susceptibility

With the progress in cancer genetics and assisted reproductive technologies, it is now possible for cancer gene mutation carriers not only to reduce cancer mortality through the targeting of surveillance and preventive therapies, but also to avoid the birth of at-risk babies through the choice of different means of reproduction. Thus, the incidence of hereditary cancer syndromes may be decreased in the future. The integration of cancer genetic testing and assisted reproductive technologies raises certain ethical, legal and social issues beyond either genetic testing or assisted reproductive technology itself. In this paper, the reproductive decisions/choices of at-risk young couples and the ethical, legal and social concerns of prenatal genetic testing and preimplantation genetic diagnosis for susceptibility to hereditary cancer syndromes are discussed. Specifically, three ethical principles related to the integration of cancer genetic testing and assisted reproductive technologies, i.e. informed choice, beneficence to children and social justice, and their implications for the responsible translation of these medical techniques into common practice of preventive medicine are highlighted.

Cancer risk in MLH1, MSH2 and MSH6 mutation carriers; different risk profiles may influence clinical management

BACKGROUND

Lynch syndrome (LS) is associated with a high risk for colorectal cancer (CRC) and extracolonic malignancies, such as endometrial carcinoma (EC). The risk is dependent of the affected mismatch repair gene. The aim of the present study was to calculate the cumulative risk of LS related cancers in proven MLH1, MSH2 and MSH6 mutation carriers.

METHODS

The studypopulation consisted out of 67 proven LS families. Clinical information including mutation status and tumour diagnosis was collected. Cumulative risks were calculated and compared using Kaplan Meier survival analysis.

RESULTS

MSH6 mutation carriers, both males and females had the lowest risk for developing CRC at age 70 years, 54% and 30% respectively and the age of onset was delayed by 3-5 years in males. With respect to endometrial carcinoma, female MSH6 mutation carriers had the highest risk at age 70 years (61%) compared to MLH1 (25%) and MSH2 (49%). Also, the age of EC onset was delayed by 5-10 years in comparison with MLH1 and MSH2.

CONCLUSIONS

Although the cumulative lifetime risk of LS related cancer is similar, MLH1, MSH2 and MSH6 mutations seem to cause distinguishable cancer risk profiles. Female MSH6 mutation carriers have a lower CRC risk and a higher risk for developing endometrial carcinoma. As a consequence, surveillance colonoscopy starting at age 30 years instead of 20-25 years is more suitable. Also, prophylactic hysterectomy may be more indicated in female MSH6 mutation carriers compared to MLH1 and MSH2 mutation carriers.