Recontact to return new or updated PALB2 genetic results in the clinical laboratory setting.

OBJECTIVE: The purpose of this study was to recontact individuals with clinically actionable test results identified through a retrospective research study and to provide a framework for laboratories to recontact patients. METHODS: Genetic testing was conducted on 2977 individuals originally referred for BRCA1 and BRCA2 hereditary breast and ovarian cancer testing that had a negative genetic test result. A gene panel was used to identify pathogenic variants in known or newly discovered genes that could explain the underlying cause of disease; however, analysis was restricted to PALB2 for the purposes of this study. A patient recontact decision tree was developed to assist in the returning of updated genetic test results to clinics and patients. RESULTS: Novel clinically actionable pathogenic variants were identified in the PALB2 gene in 18 participants (0.6%), the majority of whom were recontacted with their new or updated genetic test results. Eight individuals were unable to be recontacted; five individuals had already learnt about their new or updated findings from genetic testing outside the context of this study; three individuals prompted cascade testing in family members; two individuals were deceased. CONCLUSION: Novel pathogenic variants in PALB2 were identified in 18 individuals through retrospective gene panel testing. Recontacting these individuals regarding these new or updated findings had a range of outcomes. The process of conveying genomic results within this framework can be effectively accomplished while upholding patient autonomy, potentially leading to advantageous outcomes for patients and their families.

A model for the return and referral of all clinically significant secondary findings of genomic sequencing.

Secondary findings (SFs) identified through genomic sequencing (GS) can offer a wide range of health benefits to patients. Resource and capacity constraints pose a challenge to their clinical management; therefore, clinical workflows are needed to optimise the health benefits of SFs. In this paper, we describe a model we created for the return and referral of all clinically significant SFs, beyond medically actionable results, from GS. As part of a randomised controlled trial evaluating the outcomes and costs of disclosing all clinically significant SFs from GS, we consulted genetics and primary care experts to determine a feasible workflow to manage SFs. Consensus was sought to determine appropriate clinical recommendations for each category of SF and which clinician specialist would provide follow-up care. We developed a communication and referral plan for each category of SFs. This involved referrals to specialised clinics, such as an Adult Genetics clinic, for highly penetrant medically actionable findings. Common and non-urgent SFs, such as pharmacogenomics and carrier status results for non-family planning participants, were directed back to the family physician (FP). SF results and recommendations were communicated directly to participants to respect autonomy and to their FPs to support follow-up of SFs. We describe a model for the return and referral of all clinically significant SFs to facilitate the utility of GS and promote the health benefits of SFs. This may serve as a model for others returning GS results transitioning participants from research to clinical settings.

Great expectations: patients' preferences for clinically significant results from genomic sequencing.

We aimed to describe patient preferences for a broad range of secondary findings (SF) from genomic sequencing (GS) and factors driving preferences. We assessed preference data within a trial of the Genomics ADvISER, (SF decision aid) among adult cancer patients. Participants could choose from five categories of SF: (1) medically actionable; (2) polygenic risks; (3) rare diseases; (4) early-onset neurological diseases; and (5) carrier status. We analyzed preferences using descriptive statistics and drivers of preferences using multivariable logistic regression models. The 133 participants were predominantly European (74%) or East Asian or mixed ancestry (13%), female (90%), and aged > 50 years old (60%). The majority chose to receive SF. 97% (129/133) chose actionable findings with 36% (48/133) choosing all 5 categories. Despite the lack of medical actionability, participants were interested in receiving SF of polygenic risks (74%), carrier status (75%), rare diseases (59%), and early-onset neurologic diseases (53%). Older participants were more likely to be interested in receiving results for early-onset neurological diseases, while those exhibiting lower decisional conflict were more likely to select all categories. Our results highlight a disconnect between cancer patient preferences and professional guidelines on SF, such as ACMG's recommendations to only return medically actionable secondary findings. In addition to clinical evidence, future guidelines should incorporate patient preferences.

A comprehensive genomic reporting structure for communicating all clinically significant primary and secondary findings.

Genomic sequencing (GS) can reveal secondary findings (SFs), findings unrelated to the reason for testing, that can be overwhelming to both patients and providers. An effective approach for communicating all clinically significant primary and secondary GS results is needed to effectively manage this large volume of results. The aim of this study was to develop a comprehensive approach to communicate all clinically significant primary and SF results. A genomic test report with accompanying patient and provider letters were developed in three phases: review of current clinical reporting practices, consulting with genetic and non-genetics experts, and iterative refinement through circulation to key stakeholders. The genomic test report and consultation letters present a myriad of clinically relevant GS results in distinct, tabulated sections, including primary (cancer) and secondary findings, with in-depth details of each finding generated from exome sequencing. They provide detailed variant and disease information, personal and familial risk assessments, clinical management details, and additional resources to help support providers and patients with implementing healthcare recommendations related to their GS results. The report and consultation letters represent a comprehensive approach to communicate all clinically significant SFs to patients and providers, facilitating clinical management of GS results.

Exome and genome sequencing in adults with undiagnosed disease: a prospective cohort study.

BACKGROUND: Exome and genome sequencing have been demonstrated to increase diagnostic yield in paediatric populations, improving treatment options and providing risk information for relatives. There are limited studies examining the clinical utility of these tests in adults, who currently have limited access to this technology. METHODS: Patients from adult and cancer genetics clinics across Toronto, Ontario, Canada were recruited into a prospective cohort study evaluating the diagnostic utility of exome and genome sequencing in adults. Eligible patients were ≥18 years of age and suspected of having a hereditary disorder but had received previous uninformative genetic test results. In total, we examined the diagnostic utility of exome and genome sequencing in 47 probands and 34 of their relatives who consented to participate and underwent exome or genome sequencing. RESULTS: Overall, 17% (8/47) of probands had a pathogenic or likely pathogenic variant identified in a gene associated with their primary indication for testing. The diagnostic yield for patients with a cancer history was similar to the yield for patients with a non-cancer history (4/18 (22%) vs 4/29 (14%)). An additional 24 probands (51%) had an inconclusive result. Secondary findings were identified in 10 patients (21%); three had medically actionable results. CONCLUSIONS: This study lends evidence to the diagnostic utility of exome or genome sequencing in an undiagnosed adult population. The significant increase in diagnostic yield warrants the use of this technology. The identification and communication of secondary findings may provide added value when using this testing modality as a first-line test.

An evaluation of memory and attention in BRCA mutation carriers using an online cognitive assessment tool.

BACKGROUND: The objective of this study was to evaluate the impact of various surgical, hormonal, and lifestyle factors on memory and attention in women with a BRCA1 or BRCA2 mutation. METHODS: BRCA mutation carriers enrolled in a longitudinal study were invited to complete an online brain health assessment tool designed to screen for cognitive deficits. Four measures of memory and executive attention were assessed individually, and an overall score was compiled adjusting for age. Exposures, including preventive surgery, hormone use, and lifestyle factors, were captured by questionnaire. Performance on each of the 5 subtasks was analyzed according to various exposures. Analysis of covariance was used to compare overall scores. RESULTS: In total, 880 women completed the online cognitive assessment. The average age of the participants was 54 years (range, 23-86 years). The mean overall test score was 54.4 (range, 0-93). The individual subtask scores declined with age at test completion (P < .0001) and increased with level of education (P ≤ .01). Women who underwent a preventive oophorectomy had a significantly higher overall score compared with women who did not undergo this surgery (55.5 vs 50.5; P = .01). Reconstructive breast surgery was also associated with a higher overall score (56.5 vs 52.3; P = .005). Chemotherapy and hormone-replacement therapy were not predictive of the overall score. CONCLUSIONS: These findings are reassuring to high-risk women who undergo early surgical menopause for their cancer predisposition. Further studies are needed to evaluate cognitive function over time when memory deficits become more prevalent.

The role of digital tools in the delivery of genomic medicine: enhancing patient-centered care.

PURPOSE: Alternative models of genetic counseling are needed to meet the rising demand for genomic sequencing. Digital tools have been proposed as a method to augment traditional counseling and reduce burden on professionals; however, their role in delivery of genetic counseling is not established. This study explored the role of the Genomics ADvISER, a digital decision aid, in delivery of genomic counseling. METHODS: We performed secondary analysis of 52 pretest genetic counseling sessions that were conducted over the course of a randomized controlled trial evaluating the effectiveness of the Genomics ADvISER. As part of the trial, participants were randomized to receive standard counseling or use the tool and then speak with a counselor. A qualitative interpretive description approach using thematic analysis and constant comparison was used for analysis. RESULTS: In the delivery of genomic counseling, the Genomics ADvISER contributed to enhancing counseling by (1) promoting informed dialogue, (2) facilitating preference-sensitive deliberation, and (3) deepening personalization of decisions, all of which represent fundamental principles of patient-centered care: providing clear high-quality information, respecting patients' values, preferences, and expressed needs, and providing emotional support. CONCLUSION: This study demonstrates that our digital tool contributed to enhancing patient-centered care in the delivery of genomic counseling.

Effectiveness of the Genomics ADvISER decision aid for the selection of secondary findings from genomic sequencing: a randomized clinical trial.

PURPOSE: To evaluate the effectiveness of the Genomics ADvISER (www.genomicsadviser.com) decision aid (DA) for selection of secondary findings (SF), compared with genetic counseling alone. METHODS: A randomized controlled trial (RCT) was conducted to evaluate whether the Genomics ADvISER is superior to genetic counseling when hypothetically selecting SF. Participants were randomized to use the DA followed by discussion with a genetic counselor, or to genetic counseling alone. Surveys were administered at baseline and post-intervention. Primary outcome was decisional conflict. Secondary outcomes were knowledge, preparation for, and satisfaction with decision-making, anxiety, and length of counseling session. RESULTS: Participants (n = 133) were predominantly White/European (74%), female (90%), and ≥50 years old (60%). Decisional conflict (mean difference 0.05; P = 0.60), preparation for decision-making (0.17; P = 0.95), satisfaction with decision (-2.18; P = 0.06), anxiety (0.72; P = 0.56), and knowledge of sequencing limitations (0.14; P = 0.70) did not significantly differ between groups. However, intervention participants had significantly higher knowledge of SF (0.39; P < 0.001) and sequencing benefits (0.97; P = 0.01), and significantly shorter counseling time (24.40 minutes less; P < 0.001) CONCLUSIONS: The Genomics ADvISER did not decrease decisional conflict but reduced counseling time and improved knowledge. This decision aid could serve as an educational tool, reducing in-clinic time and potentially health care costs.

Predictors of mammographic density among women with a strong family history of breast cancer.

BACKGROUND: Mammographic density is one of the strongest risk factors for breast cancer. In the general population, mammographic density can be modified by various exposures; whether this is true for women a strong family history is not known. Thus, we evaluated the association between reproductive, hormonal, and lifestyle risk factors and mammographic density among women with a strong family history of breast cancer but no BRCA1 or BRCA2 mutation. METHODS: We included 97 premenopausal and 59 postmenopausal women (age range: 27-68 years). Risk factor data was extracted from the research questionnaire closest in time to the mammogram performed nearest to enrollment. The Cumulus software was used to measure percent density, dense area, and non-dense area for each mammogram. Multivariate generalized linear models were used to evaluate the relationships between breast cancer risk factors and measures of mammographic density, adjusting for relevant covariates. RESULTS: Among premenopausal women, those who had two live births had a mean percent density of 28.8% vs. 41.6% among women who had one live birth (P=0.04). Women with a high body weight had a lower mean percent density compared to women with a low body weight among premenopausal (17.6% vs. 33.2%; P=0.0006) and postmenopausal women (8.7% vs. 14.7%; P=0.04). Among premenopausal women, those who smoked for 14 years or longer had a lower mean dense area compared to women who smoked for a shorter duration (25.3cm2 vs. 53.1cm2; P=0.002). Among postmenopausal women, former smokers had a higher mean percent density (19.5% vs. 10.8%; P=0.003) and dense area (26.9% vs. 16.4%; P=0.01) compared to never smokers. After applying the Bonferroni correction, the association between body weight and percent density among premenopausal women remained statistically significant. CONCLUSIONS: In this cohort of women with a strong family history of breast cancer, body weight was associated with mammographic density. These findings suggest that mammographic density may explain the underlying relationship between some of these risk factors and breast cancer risk, and lend support for the inclusion of mammographic density into risk prediction models.

A review of genetic counseling for Charcot Marie Tooth disease (CMT).

Charcot Marie Tooth disease (CMT) encompasses the inherited peripheral neuropathies. While four genes have been found to cause over 90 % of genetically identifiable causes of CMT (PMP22, GJB1, MPZ, MFN2), at least 51 genes and loci have been found to cause CMT when mutated, creating difficulties for clinicians to find a genetic subtype for families. Here, the classic features of CMT as well as characteristic features of the most common subtypes of CMT are described, as well as methods for narrowing down the possible subtypes. Psychosocial concerns particular to the CMT population are identified. This is the most inclusive publication for CMT-specific genetic counseling.

Genetics Adviser: a protocol for a mixed-methods randomised controlled trial evaluating a digital platform for genetics service delivery.

INTRODUCTION: The high demand for genetic tests and limited supply of genetics professionals has created a need for alternative service delivery models. Digital tools are increasingly being used to support multiple points in the genetic testing journey; however, none are transferable across multiple clinical specialties and settings nor do they encompass the entire trajectory of the journey. We aim to evaluate the effectiveness of the Genetics Adviser, an interactive, patient-facing, online digital health tool that delivers pre-test counselling, provides support during the waiting period for results, and returns results with post-test counselling, encompassing the entire patient genetic testing journey. METHODS AND ANALYSIS: We will compare the Genetics Adviser paired with a brief genetic counselling session to genetic counselling alone in a randomised controlled trial. One hundred and forty patients who previously received uninformative genetic test results for their personal and family history of cancer will be recruited from familial cancer clinics in Toronto and offered all clinically significant results from genomic sequencing. Participants randomised into the intervention arm will use the Genetics Adviser to learn about genomic sequencing, receive pre-test counselling, support during the waiting period and results, supplemented with brief counselling from a genetic counsellor. Participants in the control arm will receive standard pre-test and post-test counselling for genomic sequencing from a genetic counsellor. Our primary outcome is decisional conflict following pre-test counselling from the Genetics Adviser+genetic counsellor or counsellor alone. Secondary outcomes include: knowledge, satisfaction with decision-making, anxiety, quality of life, psychological impact of results, empowerment, acceptability and economic impact for patients and the health system. A subset of patients will be interviewed to assess user experience. ETHICS AND DISSEMINATION: This study has been approved by Clinical Trials Ontario Streamlined Research Ethics Review System (REB#20-035). Results will be shared through stakeholder workshops, national and international conferences and peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT04725565.

Incidental findings from cancer next generation sequencing panels.

Next-generation sequencing (NGS) technologies have facilitated multi-gene panel (MGP) testing to detect germline DNA variants in hereditary cancer patients. This sensitive technique can uncover unexpected, non-germline incidental findings indicative of mosaicism, clonal hematopoiesis (CH), or hematologic malignancies. A retrospective chart review was conducted to identify cases of incidental findings from NGS-MGP testing. Inclusion criteria included: 1) multiple pathogenic variants in the same patient; 2) pathogenic variants at a low allele fraction; and/or 3) the presence of pathogenic variants not consistent with family history. Secondary tissue analysis, complete blood count (CBC) and medical record review were conducted to further delineate the etiology of the pathogenic variants. Of 6060 NGS-MGP tests, 24 cases fulfilling our inclusion criteria were identified. Pathogenic variants were detected in TP53, ATM, CHEK2, BRCA1 and APC. 18/24 (75.0%) patients were classified as CH, 3/24 (12.5%) as mosaic, 2/24 (8.3%) related to a hematologic malignancy, and 1/24 (4.2%) as true germline. We describe a case-specific workflow to identify and interpret the nature of incidental findings on NGS-MGP. This workflow will provide oncology and genetic clinics a practical guide for the management and counselling of patients with unexpected NGS-MGP findings.

Quality of life drives patients' preferences for secondary findings from genomic sequencing.

There is growing impetus to include measures of personal utility, the nonmedical value of information, in addition to clinical utility in health technology assessment (HTA) of genomic tests such as genomic sequencing (GS). However, personal utility and clinical utility are challenging to define and measure. This study aimed to explore what drives patients' preferences for hypothetically learning medically actionable and non-medically actionable secondary findings (SF), capturing clinical and personal utility; this may inform development of measures to evaluate patient outcomes following return of SF. Semi-structured interviews were conducted with adults with a personal or family cancer history participating in a trial of a decision aid for selection of SF from genomic sequencing (GS) ( www.GenomicsADvISER.com ). Interviews were analyzed thematically using constant comparison. Preserving health-related and non-health-related quality of life was an overarching motivator for both learning and not learning SF. Some participants perceived that learning SF would help them "have a good quality of life" through informing actions to maintain physical health or leading to psychological benefits such as emotional preparation for disease. Other participants preferred not to learn SF because results "could ruin your quality of life," such as by causing negative psychological impacts. Measuring health-related and non-health-related quality of life may capture outcomes related to clinical and personal utility of GS and SF, which have previously been challenging to measure. Without appropriate measures, generating and synthesizing evidence to evaluate genomic technologies such as GS will continue to be a challenge, and will undervalue potential benefits of GS and SF.

An update on genetic risk assessment and prevention: the role of genetic testing panels in breast cancer.

Introduction: In the past 5 years, multi-gene panels have replaced the practice of BRCA1 and BRCA2 genetic testing in cases of suspected inherited breast cancer susceptibility. A variety of genes have been included on these panels without certainty of their clinical utility. Pertinent current and historical literature was reviewed to provide an up-to-date snapshot of the changing landscape of the use of gene panel tests in the context of breast cancer. Areas covered: Following a recent review of the evidence, 10 genes have been found to have definitive evidence of increased breast cancer risk with variable penetrance. Here, we review the recent changes to the practice of multi-gene panel use in breast cancer diagnoses, including an update on next generation sequencing, alternative models of genetic testing, considerations when ordering these panel tests, and recommendations for management in identified carriers for a variety of genes. A comparison of screening recommendations and carrier frequencies from recent studies is also explored. Lastly, we consider what the future of hereditary oncologic genetic testing holds. Expert opinion: The transition to multi-gene panels in breast cancer patients has improved the likelihood of capturing a rare variant in a well-established gene associated with hereditary breast cancer (e.g. BRCA1 and BRCA2, TP53). There is also an increase in the likelihood of uncovering an uncertain result. This could be in the form of a variant of uncertain significance, or a pathogenic variant in a gene with questionable breast cancer risk-association. Concurrently, a changing landscape of who orders genetic tests will improve access to genetic testing. This pervasiveness of genetic testing must be accompanied with increased genetic literacy in all health-care providers, and access to support from genetics professionals for management of patients and at-risk family members.

Development of patient "profiles" to tailor counseling for incidental genomic sequencing results.

Guidelines recommend that providers engage patients in shared decision-making about receiving incidental results (IR) prior to genomic sequencing (GS), but this can be time-consuming, given the myriad of IR and variation in patients' preferences. We aimed to develop patient profiles to inform pre-test counseling for IR. We conducted semi-structured interviews with participants as a part of a randomized trial of the GenomicsADvISER.com, a decision aid for selecting IR. Interviews explored factors participants considered when deliberating over learning IR. Interviews were analyzed by thematic analysis and constant comparison. Participants were mostly female (28/31) and about half of them were over the age of 50 (16/31). We identified five patient profiles that reflect common contextual factors, attitudes, concerns, and perceived utility of IR. Information Enthusiasts self-identified as "planners" and valued learning most or all IR to enable planning and disease prevention because "knowledge is power". Concerned Individuals defined themselves as "anxious," and were reluctant to learn IR, anticipating negative psychological impacts from IR. Contemplators were discerning about the value and limitations of IR, weighing health benefits with the impacts of not being able to "un-know" information. Individuals of Advanced Life Stage did not consider IR relevant for themselves and primarily considered their implications for family members. Reassurance Seekers were reassured by previous negative genetic test results which shaped their expectations for receiving no IR: "hopefully [GS will] be negative, too. And then I can rest easy". These profiles could inform targeted counseling for IR by providing a framework to address common values, concerns. and misconceptions.

Health outcomes, utility and costs of returning incidental results from genomic sequencing in a Canadian cancer population: protocol for a mixed-methods randomised controlled trial.

INTRODUCTION: Genomic sequencing has rapidly transitioned into clinical practice, improving diagnosis and treatment options for patients with hereditary disorders. However, large-scale implementation of genomic sequencing faces challenges, especially with regard to the return of incidental results, which refer to genetic variants uncovered during testing that are unrelated to the primary disease under investigation, but of potential clinical significance. High-quality evidence evaluating health outcomes and costs of receiving incidental results is critical for the adoption of genomic sequencing into clinical care and to understand the unintended consequences of adoption of genomic sequencing. We aim to evaluate the health outcomes and costs of receiving incidental results for patients undergoing genomic sequencing. METHODS AND ANALYSIS: We will compare health outcomes and costs of receiving, versus not receiving, incidental results for adult patients with cancer undergoing genomic sequencing in a mixed-methods randomised controlled trial. Two hundred and sixty patients who have previously undergone first or second-tier genetic testing for cancer and received uninformative results will be recruited from familial cancer clinics in Toronto, Ontario. Participants in both arms will receive cancer-related results. Participants in the intervention arm have the option to receive incidental results. Our primary outcome is psychological distress at 2 weeks following return of results. Secondary outcomes include behavioural consequences, clinical and personal utility assessed over the 12 months after results are returned and health service use and costs at 12 months and 5 years. A subset of participants and providers will complete qualitative interviews about utility of incidental results. ETHICS AND DISSEMINATION: This study has been approved by Clinical Trials Ontario Streamlined Research Ethics Review System that provides ethical review and oversight for multiple sites participating in the same clinical trial in Ontario.Results from the trial will be shared through stakeholder workshops, national and international conferences, and peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT03597165.

Selecting a BRCA risk assessment model for use in a familial cancer clinic.

BACKGROUND: Risk models are used to calculate the likelihood of carrying a BRCA1 or BRCA2 mutation. We evaluated the performances of currently-used risk models among patients from a large familial program using the criteria of high sensitivity, simple data collection and entry and BRCA score reporting. METHODS: Risk calculations were performed by applying the BRCAPRO, Manchester, Penn II, Myriad II, FHAT, IBIS and BOADICEA models to 200 non-BRCA carriers and 100 BRCA carriers, consecutively tested between August 1995 and March 2006. Areas under the receiver operating characteristic curves (AUCs) were determined and sensitivity and specificity were calculated at the conventional testing thresholds. In addition, subset analyses were performed for low and high risk probands. RESULTS: The BRCAPRO, Penn II, Myriad II, FHAT and BOADICEA models all have similar AUCs of approximately 0.75 for BRCA status. The Manchester and IBIS models have lower AUCs (0. and 0.47 respectively). At the conventional testing thresholds, the sensitivities and specificities for a BRCA mutation were, respectively, as follows: BRCAPRO (0.75, 0.62), Manchester (0.58,0.71), Penn II (0.93,0.31), Myriad II (0.71,0.63), FHAT (0.70,0.63), IBIS (0.20,0.74), BOADICEA (0.70, 0.65). CONCLUSION: The Penn II model most closely met the criteria we established and this supports the use of this model for identifying individuals appropriate for genetic testing at our facility. These data are applicable to other familial clinics provided that variations in sample populations are taken into consideration.

Prospective evaluation of body size and breast cancer risk among BRCA1 and BRCA2 mutation carriers.

BACKGROUND: Although evidence suggests that larger body size in early life confers lifelong protection from developing breast cancer, few studies have investigated the relationship between body size and breast cancer risk among BRCA mutation carriers. Therefore, we conducted a prospective evaluation of body size and the risk of breast cancer among BRCA mutation carriers. METHODS: Current height and body mass index (BMI) at age 18 were determined from baseline questionnaires. Current BMI and weight change since age 18 were calculated from updated biennial follow-up questionnaires. Cox proportional hazards models were used to estimate the hazard ratio (HR) and 95% confidence interval (CI). RESULTS: Among 3734 BRCA mutation carriers, there were 338 incident breast cancers over a mean follow-up of 5.5 years. There was no association between height, current BMI or weight change and breast cancer risk. Women with BMI at age 18 ≥22.1 kg/m2 had a decreased risk of developing post-menopausal breast cancer compared with women with a BMI at age 18 between 18.8 and 20.3 kg/m2 (HR 0.49; 95% CI 0.30-0.82; P = 0.006). BMI at age 18 was not associated with risk of pre-menopausal breast cancer. CONCLUSIONS: There was no observed association between height, current BMI and weight change and risk of breast cancer. The inverse relationship between greater BMI at age 18 and post-menopausal breast cancer further supports a role of early rather than current or adulthood exposures for BRCA-associated breast cancer development. Future studies with longer follow-up and additional measures of adiposity are necessary to confirm these findings.

Evaluation of a decision aid for incidental genomic results, the Genomics ADvISER: protocol for a mixed methods randomised controlled trial.

INTRODUCTION: Genome sequencing, a novel genetic diagnostic technology that analyses the billions of base pairs of DNA, promises to optimise healthcare through personalised diagnosis and treatment. However, implementation of genome sequencing faces challenges including the lack of consensus on disclosure of incidental results, gene changes unrelated to the disease under investigation, but of potential clinical significance to the patient and their provider. Current recommendations encourage clinicians to return medically actionable incidental results and stress the importance of education and informed consent. Given the shortage of genetics professionals and genomics expertise among healthcare providers, decision aids (DAs) can help fill a critical gap in the clinical delivery of genome sequencing. We aim to assess the effectiveness of an interactive DA developed for selection of incidental results. METHODS AND ANALYSIS: We will compare the DA in combination with a brief Q&A session with a genetic counsellor to genetic counselling alone in a mixed-methods randomised controlled trial. Patients who received negative standard cancer genetic results for their personal and family history of cancer and are thus eligible for sequencing will be recruited from cancer genetics clinics in Toronto. Our primary outcome is decisional conflict. Secondary outcomes are knowledge, satisfaction, preparation for decision-making, anxiety and length of session with the genetic counsellor. A subset of participants will complete a qualitative interview about preferences for incidental results. ETHICS AND DISSEMINATION: This study has been approved by research ethics boards of St. Michael's Hospital, Mount Sinai Hospital and Sunnybrook Health Sciences Centre. This research poses no significant risk to participants. This study evaluates the effectiveness of a novel patient-centred tool to support clinical delivery of incidental results. Results will be shared through national and international conferences, and at a stakeholder workshop to develop a consensus statement to optimise implementation of the DA in practice. TRIAL REGISTRATION NUMBER: NCT03244202; Pre-results.