Breast cancer risk stratification using genetic and non-genetic risk assessment tools for 246,142 women in the UK Biobank

PurposeThe benefit of using individual risk prediction tools to identify high-risk individuals for breast cancer (BC) screening is uncertain, despite the personalized approach of risk-based screening.MethodsWe studied the overlap of predicted high-risk individuals among 246,142 women enrolled in the UK Biobank. Risk predictors assessed include the Gail model (Gail), BC family history (FH, binary), BC polygenic risk score (PRS), and presence of loss-of-function (LoF) variants in BC predisposition genes. Youden J-index was used to select optimal thresholds for defining high-risk.ResultsIn total, 147,399 were considered at high risk for developing BC within the next 2 years by at least 1 of the 4 risk prediction tools examined (Gail_2-year > 0.5%: 47%, PRS_2-yea r > 0.7%: 30%, FH: 6%, and LoF: 1%); 92,851 (38%) were flagged by only 1 risk predictor. The overlap between individuals flagged as high-risk because of genetic (PRS) and Gail model risk factors was 30%. The best-performing combinatorial model comprises a union of high-risk women identified by PRS, FH, and, LoF (AUC_2-year [95% CI]: 62.2 [60.8 to 63.6]). Assigning individual weights to each risk prediction tool increased discriminatory ability.ConclusionRisk-based BC screening may require a multipronged approach that includes PRS, predisposition genes, FH, and other recognized risk factors.     

Breast cancer risk stratification in women of screening age: Incremental effects of adding mammographic density,polygenic risk,and a gene panel

PurposeThere is great promise in breast cancer risk stratification to target screening and prevention. It is unclear whether adding gene panels to other risk tools improves breast cancer risk stratification and adds discriminatory benefit on a population basis.MethodsIn total, 10,025 of 57,902 women aged 46 to 73 years in the Predicting Risk of Cancer at Screening study provided DNA samples. A case–control study was used to evaluate breast cancer risk assessment using polygenic risk scores (PRSs), cancer gene panel (n = 33), mammographic density (density residual [DR]), and risk factors collected using a self-completed 2-page questionnaire (Tyrer-Cuzick [TC] model version 8). In total, 525 cases and 1410 controls underwent gene panel testing and PRS calculation (18, 143, and/or 313 single-nucleotide polymorphisms [SNPs]).ResultsActionable pathogenic variants (PGVs) in BRCA1/2 were found in 1.7% of cases and 0.55% of controls, and overall PGVs were found in 6.1% of cases and 1.3% of controls. A combined assessment of TC8-DR-SNP313 and gene panel provided the best risk stratification with 26.1% of controls and 9.7% of cases identified at <1.4% 10-year risk and 9.01% of controls and 23.3% of cases at ≥8% 10-year risk. Because actionable PGVs were uncommon, discrimination was identical with/without gene panel (with/without: area under the curve = 0.67, 95% CI = 0.64-0.70). Only 7 of 17 PGVs in cases resulted in actionable risk category change. Extended case (n = 644)–control (n = 1779) series with TC8-DR-SNP143 identified 18.9% of controls and only 6.4% of stage 2+ cases at <1.4% 10-year risk and 20.7% of controls and 47.9% of stage 2+ cases at ≥5% 10-year risk.ConclusionFurther studies and economic analysis will determine whether adding panels to PRS is a cost-effective strategy for risk stratification.     

Communicating polygenic risk scores in the familial breast cancer clinic

ObjectiveTo describe the communication of polygenic risk scores (PRS) in the familial breast cancer setting.MethodsConsultations between genetic healthcare providers (GHP) and female patients who received their PRS for breast cancer risk were recorded (n = 65). GHPs included genetic counselors (n = 8) and medical practitioners (n = 5) (i.e. clinical geneticists and oncologists). A content analysis was conducted and logistic regression was used to assess differences in communication behaviors between genetic counselors (n = 8) and medical practitioners (n = 5).ResultsOf the 65 patients, 31 (47.7 %) had a personal history of breast cancer, 18 of whom received an increased PRS (relative risk >1.2). 25/34 unaffected patients received an increased PRS. Consultations were primarily clinician-driven and focused on biomedical information. There was little difference between the biomedical information provided by genetic counselors and medical practitioners. However, genetic counselors were significantly more likely to utilize strategies to build patient rapport and counseling techniques.ConclusionsOur findings provide one of the earliest reports on how breast cancer PRSs are communicated to women.Practice implicationsKey messages for communicating PRSs were identified, namely: discussing differences between polygenic and monogenic testing, the multifactorial nature of breast cancer risk, polygenic inheritance and current limitation of PRSs.     

Breast cancer polygenic risk scores derived in White European populations are not calibrated for women of Ashkenazi Jewish descent

PurposePolygenic risk scores (PRSs) are a major component of accurate breast cancer (BC) risk prediction but require ethnicity-specific calibration. Ashkenazi Jewish (AJ) population is assumed to be of White European (WE) origin in some commercially available PRSs despite differing effect allele frequencies (EAFs). We conducted a case-control study of WE and AJ women from the Predicting Risk of Cancer at Screening Study. The Breast Cancer in Northern Israel Study provided a separate AJ population–based case-control validation series.MethodsAll women underwent Illumina OncoArray single-nucleotide variation (SNV; formerly single-nucleotide polymorphism [SNP]) analysis. Two PRSs were assessed, SNV142 and SNV78. A total of 221 of 2243 WE women (discovery: cases = 111; controls = 110; validation: cases = 651; controls = 1772) and 221 AJ women (cases = 121; controls = 110) women were included from the UK study; the Israeli series consisted of 2045 AJ women (cases = 1331; controls = 714). EAFs were obtained from the Genome Aggregation Database.ResultsIn the UK study, the mean SNV142 PRS demonstrated good calibration and discrimination in WE population, with mean PRS of 1.33 (95% CI 1.18-1.48) in cases and 1.01 (95% CI 0.89-1.13) in controls. In AJ women from Manchester, the mean PRS of 1.54 (1.38-1.70) in cases and 1.20 (1.08-1.32) in controls demonstrated good discrimination but overestimation of BC relative risk. After adjusting for EAFs for the AJ population, mean risk was corrected (mean SNV142 PRS cases = 1.30 [95% CI 1.16-1.44] and controls = 1.02 [95% CI 0.92-1.12]). This was recapitulated in the larger Israeli data set with good discrimination (area under the curve = 0.632 [95% CI 0.607-0.657] for SNV142).ConclusionAJ women should not be given BC relative risk predictions based on PRSs calibrated to EAFs from the WE population. PRSs need to be recalibrated using AJ-derived EAFs. A simple recalibration using the mean PRS adjustment ratio likely performs well.     

Returning integrated genomic risk and clinical recommendations: The eMERGE study

PurposeAssessing the risk of common, complex diseases requires consideration of clinical risk factors as well as monogenic and polygenic risks, which in turn may be reflected in family history. Returning risks to individuals and providers may influence preventive care or use of prophylactic therapies for those individuals at high genetic risk.MethodsTo enable integrated genetic risk assessment, the eMERGE (electronic MEdical Records and GEnomics) network is enrolling 25,000 diverse individuals in a prospective cohort study across 10 sites. The network developed methods to return cross-ancestry polygenic risk scores, monogenic risks, family history, and clinical risk assessments via a genome-informed risk assessment (GIRA) report and will assess uptake of care recommendations after return of results.ResultsGIRAs include summary care recommendations for 11 conditions, education pages, and clinical laboratory reports. The return of high-risk GIRA to individuals and providers includes guidelines for care and lifestyle recommendations. Assembling the GIRA required infrastructure and workflows for ingesting and presenting content from multiple sources. Recruitment began in February 2022.ConclusionReturn of a novel report for communicating monogenic, polygenic, and family history-based risk factors will inform the benefits of integrated genetic risk assessment for routine health care.     

Polygenic risk scores for prediction of breast cancer risk in Asian populations

PurposeNon-European populations are under-represented in genetics studies, hindering clinical implementation of breast cancer polygenic risk scores (PRSs). We aimed to develop PRSs using the largest available studies of Asian ancestry and to assess the transferability of PRS across ethnic subgroups.MethodsThe development data set comprised 138,309 women from 17 case-control studies. PRSs were generated using a clumping and thresholding method, lasso penalized regression, an Empirical Bayes approach, a Bayesian polygenic prediction approach, or linear combinations of multiple PRSs. These PRSs were evaluated in 89,898 women from 3 prospective studies (1592 incident cases).ResultsThe best performing PRS (genome-wide set of single-nucleotide variations [formerly single-nucleotide polymorphism]) had a hazard ratio per unit SD of 1.62 (95% CI = 1.46-1.80) and an area under the receiver operating curve of 0.635 (95% CI = 0.622-0.649). Combined Asian and European PRSs (333 single-nucleotide variations) had a hazard ratio per SD of 1.53 (95% CI = 1.37-1.71) and an area under the receiver operating curve of 0.621 (95% CI = 0.608-0.635). The distribution of the latter PRS was different across ethnic subgroups, confirming the importance of population-specific calibration for valid estimation of breast cancer risk.ConclusionPRSs developed in this study, from association data from multiple ancestries, can enhance risk stratification for women of Asian ancestry.     

Development and evaluation of polygenic risk scores for prediction of endometrial cancer risk in European women

PurposeSingle-nucleotide variations (SNVs) (formerly single-nucleotide polymorphism [SNV]) influence genetic predisposition to endometrial cancer. We hypothesized that a polygenic risk score (PRS) comprising multiple SNVs may improve endometrial cancer risk prediction for targeted screening and prevention.MethodsWe developed PRSs from SNVs identified from a systematic review of published studies and suggestive SNVs from the Endometrial Cancer Association Consortium. These were tested in an independent study of 555 surgically-confirmed endometrial cancer cases and 1202 geographically-matched controls from Manchester, United Kingdom and validated in 1676 cases and 116,960 controls from the UK Biobank (UKBB).ResultsAge and body mass index predicted endometrial cancer in both data sets (Manchester: area under the receiver operator curve [AUC] = 0.77, 95% CI = 0.74-0.80; UKBB: AUC = 0.74, 95% CI = 0.73-0.75). The AUC for PRS19, PRS24, and PRS72 were 0.58, 0.55, and 0.57 in the Manchester study and 0.56, 0.54, and 0.54 in UKBB, respectively. For PRS19, women in the third tertile had a 2.1-fold increased risk of endometrial cancer compared with those in the first tertile of the Manchester study (odds ratio = 2.08, 95% CI = 1.61-2.68, P_trend = 5.75E–9). Combining PRS19 with age and body mass index improved discriminatory power (Manchester study: AUC = 0.79, 95% CI = 0.76-0.82; UKBB: AUC =0.75, 95% CI = 0.73-0.76).ConclusionAn endometrial cancer risk prediction model incorporating a PRS derived from multiple SNVs may help stratify women for screening and prevention strategies.     

Development and evaluation of a novel educational program for providers on the use of polygenic risk scores

PurposeThis study aimed to develop an online educational program for using polygenic risk score (PRS) for breast and ovarian cancer risk assessments and to evaluate the impact on the attitudes, confidence, knowledge, and preparedness of genetic health care providers (GHPs).MethodsThe educational program comprises an online module that covers the theoretical aspects of PRS and a facilitated virtual workshop with prerecorded role-plays and case discussions. Data were collected in pre- and posteducation surveys. Eligible participants were GHPs working in Australian familial cancer clinics registered to recruit patients for a breast and ovarian cancer PRS clinical trial (n = 12).ResultsA total of 124 GHPs completed the PRS education, of whom 80 (64%) and 67 (41%) completed the pre- and posteducation surveys, respectively. Before education, GHPs reported limited experience, confidence, and preparedness using PRS, but they recognized its potential benefits. After education, GHPs indicated improved attitudes (P ≤ .001), confidence (P ≤ .001), knowledge (P ≤ .001), and preparedness (P ≤ .001) to use PRS. Most GHPs thought that the program entirely met their learning needs (73%) and was completely relevant to their clinical practice (88%). GHPs identified PRS implementation barriers, including limited funding models, diversity issues, and need for clinical guidelines.ConclusionOur education program improved GHP attitudes, confidence, knowledge, and preparedness for using PRS/personalized risk and provides a framework for the development of future programs.     

Development and pilot testing of an online screening decision aid for men with a family history of prostate cancer

Objective

This study aimed to develop and pilot test an online screening decision aid (DA) for men with a family history of prostate cancer.

Methods

Eligible men (with no previous prostate cancer diagnosis) were recruited through relatives attending a urology outpatient clinic. Men evaluated the DA in two stages. First, they appraised a paper-based version using a questionnaire (n = 22). Second, the same men were asked to reflect on an interactive web-based version via a semi-structured telephone interview (n = 20).

Results

Men evaluated both forms of the DA positively. Of the paper-based version, the majority of participants found the DA useful (91%), and that it contained enough information to make a screening decision (73%). All participants reported that the online DA was easy to use and navigate. Most participants reported that a website was their preferred mode of receiving prostate cancer screening information (70%).

Conclusion

The developed DA may represent the first online decision-making tool designed specifically for men with a family history prostate cancer that presents age and risk specific information to the user.

Practice implications

Comprehensive evaluations of the efficacy and impact of educational interventions such as this are crucial to improve services for individuals making informed screening decisions.     

Performance of polygenic risk scores for cancer prediction in a racially diverse academic biobank

PurposeGenome-wide association studies have identified hundreds of single nucleotide variations (formerly single nucleotide polymorphisms) associated with several cancers, but the predictive ability of polygenic risk scores (PRSs) is unclear, especially among non-Whites.MethodsPRSs were derived from genome-wide significant single-nucleotide variations for 15 cancers in 20,079 individuals in an academic biobank. We evaluated the improvement in discriminatory accuracy by including cancer-specific PRS in patients of genetically-determined African and European ancestry.ResultsAmong the individuals of European genetic ancestry, PRSs for breast, colon, melanoma, and prostate were significantly associated with their respective cancers. Among the individuals of African genetic ancestry, PRSs for breast, colon, prostate, and thyroid were significantly associated with their respective cancers. The area under the curve of the model consisting of age, sex, and principal components was 0.621 to 0.710, and it increased by 1% to 4% with the inclusion of PRS in individuals of European genetic ancestry. In individuals of African genetic ancestry, area under the curve was overall higher in the model without the PRS (0.723-0.810) but increased by <1% with the inclusion of PRS for most cancers.ConclusionPRS moderately increased the ability to discriminate the cancer status in individuals of European but not African ancestry. Further large-scale studies are needed to identify ancestry-specific genetic factors in non-White populations to incorporate PRS into cancer risk assessment.     

Optimization of polygenic risk scores in BRCA1/2 pathogenic variant heterozygotes in epithelial ovarian cancer

PurposeA third of familial epithelial ovarian cancer (EOC) is explained by BRCA1/2 pathogenic variants. Polygenic risk scores (PRSs) for BRCA1/2 heterozygotes associated with EOC have been created, but impact of combination with clinical and hormonal risk factors is unclear.MethodsWe genotyped 300 cases and 355 controls and constructed modified PRSs based on those validated by Barnes et al. Model discrimination and EOC risk was assessed by area under the curve (AUC) values and difference between lowest and highest quintile odds ratios (ORs). We investigated model optimization using logistic regression to combine models with clinical and hormonal data.ResultsUnadjusted AUC values ranged from 0.526 to 0.551 with 2.2- to 2.3-fold increase in OR between lowest and highest quintiles (BRCA1 heterozygotes) and 0.574 to 0.585 AUC values with a 6.3- to 7.7-fold increase (BRCA2 heterozygotes). The optimized model (parity, age at menarche, menopause, and first full-term pregnancy) estimated AUC values of 0.872 to 0.876 and 21- to 23-fold increase in OR (BRCA1 heterozygotes) and AUC values of 0.857 to 0.867 and 40- to 41-fold increase (BRCA2 heterozygotes).ConclusionThe combination of PRS with age, family history, and hormonal factors significantly improved the EOC risk discrimination ability. However, the contribution of the PRS was small. Larger prospective studies are needed to assess if combined-PRS models could provide information to inform risk-reducing decisions.     

Validation of lung cancer polygenic risk scores in a high-risk case-control cohort

PurposeScreening with low-dose computed tomography reduces lung cancer (LC) mortality. Risk prediction models used for screening selection do not include genetic variables. Here, we investigated the performance of previously published polygenic risk scores (PRSs) for LC, considering their potential to improve screening selection.MethodsWe validated 9 PRSs in a high-risk case-control cohort, comprising genotype data from 652 surgical patients with LC and 550 cancer-free, high-risk (PLCO_M2012 score ≥ 1.51%) participants of the Manchester Lung Health Check, a community-based LC screening program (n = 550). Discrimination (area under the curve [AUC]) between cases and controls was assessed for each PRS independently and alongside clinical risk factors.ResultsMedian age was 67 years, 53% were female, 46% were current smokers, and 76% were National Lung Screening Trial eligible. Median PLCO_M2012 score among controls was 3.4%, 80% of cases were early stage. All PRSs significantly improved discrimination, AUC increased between +0.002 (P = .02) and +0.015 (P < .0001), compared with clinical risk factors alone. The best-performing PRS had an independent AUC of 0.59. Two novel loci, in the DAPK1 and MAGI2 genes, were significantly associated with LC risk.ConclusionPRSs may improve LC risk prediction and screening selection. Further research, particularly examining clinical utility and cost-effectiveness, is required.     

Primary care physician use of patient race and polygenic risk scores in medical decision-making

PurposeThe use of patient race in medicine is controversial for its potential either to exacerbate or address health disparities. Polygenic risk scores (PRSs) have emerged as a tool for risk stratification models used in preventive medicine. We examined whether PRS results affect primary care physician (PCP) medical decision-making and whether that effect varies by patient race.MethodsUsing an online survey with a randomized experimental design among PCPs in a national database, we ascertained decision-making around atherosclerotic cardiovascular disease prevention and prostate cancer screening for case scenario patients who were clinically identical except for randomized reported race.ResultsAcross 369 PCPs (email open rate = 10.8%, partial completion rate = 93.7%), recommendations varied with PRS results in expected directions (low-risk results, no available PRS results, and high-risk results). Still, physicians randomized to scenarios with Black patients were more likely to recommend statin therapy than those randomized to scenarios with White patients (odds ratio = 1.74, 95% CI = 1.16-2.59, P = .007) despite otherwise identical clinical profiles and independent of PRS results. Similarly, physicians were more likely to recommend prostate cancer screening for Black patients than for White patients (odds ratio = 1.58, 95% CI = 1.06-2.35, P = .025) despite otherwise identical clinical and genetic profiles.ConclusionDespite advances in precision risk stratification, physicians will likely continue to use patient race implicitly or explicitly in medical decision-making.     

Polygenic risk score as a possible tool for identifying familial monogenic causes of complex diseases

PurposeThe study aimed to evaluate whether polygenic risk scores could be helpful in addition to family history for triaging individuals to undergo deep-depth diagnostic sequencing for identifying monogenic causes of complex diseases.MethodsAmong 44,550 exome-sequenced European ancestry UK Biobank participants, we identified individuals with a clinically reported or computationally predicted monogenic pathogenic variant for breast cancer, bowel cancer, heart disease, diabetes, or Alzheimer disease. We derived polygenic risk scores for these diseases. We tested whether a polygenic risk score could identify rare pathogenic variant heterozygotes among individuals with a parental disease history.ResultsMonogenic causes of complex diseases were more prevalent among individuals with a parental disease history than in the rest of the population. Polygenic risk scores showed moderate discriminative power to identify familial monogenic causes. For instance, we showed that prescreening the patients with a polygenic risk score for type 2 diabetes can prioritize individuals to undergo diagnostic sequencing for monogenic diabetes variants and reduce needs for such sequencing by up to 37%.ConclusionAmong individuals with a family history of complex diseases, those with a low polygenic risk score are more likely to have monogenic causes of the disease and could be prioritized to undergo genetic testing.     

Systematic evaluation of narrow-sense validity of polygenic risk score for prostate cancer in a Chinese prostate biopsy cohort

The aim of this study was to assess the narrow-sense validity of polygenic risk score (PRS) for prostate cancer (PCa) in a Chinese prostate biopsy cohort. We performed an observational prospective study with 2640 men who underwent prostate biopsy. Germline DNA samples were genotyped and PRS was calculated for each subject using 17 PCa risk-associated genetic variants. Additional GWAS data of the ChinaPCa dataset was also used to compliment the evaluation process. The mean PRS was 1.02 in patients with negative biopsy results, which met the baseline benchmark. The mean PRS was significantly higher in the PCa cases (1.32 vs. 1.02, p = 5.56 × 10⁻¹⁷). Significant dose–response associations between PRS values and odds ratios for PCa were observed. However, the raw calibration slope was 0.524 and the average bias score between the observed risk and uncorrected PRS value was 0.307 in the entire biopsy cohort. After applying a correction factor derived from a training set, the corrected calibration slope improved to 1.002 in a testing set. Similar and satisfied results were also seen in the ChinaPCa dataset and two datasets combined, while the calibration results were inaccurate when the calibration process were performed mutually between two different study populations. In conclusion, assessing the narrow-sense validity of PRS is necessary prior to its clinical implementation for accurate individual risk assessment.     

Education and electronic medical records and genomics network,challenges, and lessons learned from a large-scale clinical trial using polygenic risk scores

Polygenic risk scores (PRS) have potential to improve health care by identifying individuals that have elevated risk for common complex conditions. Use of PRS in clinical practice, however, requires careful assessment of the needs and capabilities of patients, providers, and health care systems. The electronic Medical Records and Genomics (eMERGE) network is conducting a collaborative study which will return PRS to 25,000 pediatric and adult participants. All participants will receive a risk report, potentially classifying them as high risk (∼2-10% per condition) for 1 or more of 10 conditions based on PRS. The study population is enriched by participants from racial and ethnic minority populations, underserved populations, and populations who experience poorer medical outcomes.All 10 eMERGE clinical sites conducted focus groups, interviews, and/or surveys to understand educational needs among key stakeholders—participants, providers, and/or study staff. Together, these studies highlighted the need for tools that address the perceived benefit/value of PRS, types of education/support needed, accessibility, and PRS-related knowledge and understanding. Based on findings from these preliminary studies, the network harmonized training initiatives and formal/informal educational resources.This paper summarizes eMERGE’s collective approach to assessing educational needs and developing educational approaches for primary stakeholders. It discusses challenges encountered and solutions provided.     

Exome sequencing identifies RASSF1 and KLK3 germline variants in an Iranian multiple-case breast cancer family

Breast cancer is the most frequent malignancy among women in both developed and developing countries. Although several genes have been identified to harbor germline variants contributing to breast cancer risk, much of the heritability for breast cancer is yet undefined. In the present study, we have performed exome sequencing to detect susceptibility genes in an Iranian family with five first-degree family members affected with breast cancer. We identified novel candidate variants with predicted pathogenicity in RASSF1, KLK3 and FAM81B. The RASSF1 and KLK3 variants, but not the FAM81B variant, partially co-segregated with disease in the investigated pedigree and were not found in additional screenings outside the specific family. RASSF1 p.S135F is a missense substitution abolishing the ATM phosphorylation site, and KLK3 variant p.M1? is a deletion at the initiation codon that is predicted to abolish translation to the functional kallikrein protease, PSA. Our study suggests germline variation in RASSF1 and KLK3 as potential candidate contributors to familial breast cancer predisposition and illustrates the difficulties to determine the causal genetic risk factor among novel variants restricted to a single family.