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PURPOSE With the availability of multigene panel testing (MGPT) for hereditary cancer risk assessment, clinicians need to assess the likelihood of pathogenic germline variants (PGVs) across numerous genes in parallel. This study's aim was to develop and validate a clinical prediction model (PREMMplus) for MGPT risk assessment. MATERIALS AND METHODS PREMMplus was developed in a single-institution cohort of 7,280 individuals who had undergone MGPT. Logistic regression models with Least Absolute Shrinkage and Selection Operator regularization were used to examine candidate predictors (age, sex, ethnicity, and personal/family history of 18 cancers/neoplasms) to estimate one's likelihood of carrying PGVs in 19 genes (broadly categorized by phenotypic overlap and/or relative penetrance: 11 category A [ APC, BRCA1/ 2, CDH1, EPCAM, MLH1, MSH2, MSH6, biallelic MUTYH, PMS2, and TP53] and eight category B genes [ ATM, BRIP1, CDKN2A, CHEK2, PALB2, PTEN, RAD51C, and RAD51D]). Model performance was validated in nonoverlapping data sets of 8,691 and 14,849 individuals with prior MGPT ascertained from clinic- and laboratory-based settings, respectively. RESULTS PREMMplus (score ≥ 2.5%) had 93.9%, 91.7%, and 89.3% sensitivity and 98.3%, 97.5%, and 97.8% negative-predictive value (NPV) for identifying category A gene PGV carriers in the development and validation cohorts, respectively. PREMMplus assessment (score ≥ 2.5%) had 89.9%, 85.6%, and 84.2% sensitivity and 95.0%, 93.5%, and 93.5% NPV, respectively, for identifying category A/B gene PGV carriers. Decision curve analyses support MGPT for individuals predicted to have ≥ 2.5% probability of a PGV. CONCLUSION PREMMplus accurately identifies individuals with PGVs in a diverse spectrum of cancer susceptibility genes with high sensitivity/NPV. Individuals with PREMMplus scores ≥ 2.5% should be considered for MGPT.

Supplementary Table 1 shows number of TAP cases per site

Educational Content on the Color Genomics Website

Up to 10% of patients with pancreatic ductal adenocarcinoma (PDAC) carry underlying germline pathogenic variants in cancer susceptibility genes. The GENetic Education Risk Assessment and TEsting (GENERATE) study aimed to evaluate novel methods of genetic education and testing in relatives of patients with PDAC. Eligible individuals had a family history of PDAC and a relative with a germline pathogenic variant in APC, ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, or TP53 genes. Participants were recruited at six academic cancer centers and through social media campaigns and patient advocacy efforts. Enrollment occurred via the study website (https://GENERATEstudy.org) and all participation, including collecting a saliva sample for genetic testing, could be done from home. Participants were randomized to one of two remote methods that delivered genetic education about the risks of inherited PDAC and strategies for surveillance. The primary outcome of the study was uptake of genetic testing. From 5/8/2019 to 5/6/2020, 49 participants were randomized to each of the intervention arms. Overall, 90 of 98 (92%) of randomized participants completed genetic testing. The most frequently detected pathogenic variants included those in BRCA2 (N = 15, 17%), ATM (N = 11, 12%), and CDKN2A (N = 4, 4%). Participation in the study remained steady throughout the onset of the Coronavirus disease (COVID-19) pandemic. Preliminary data from the GENERATE study indicate success of remote alternatives to traditional cascade testing, with genetic testing rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for PDAC interception approaches.Prevention Relevance:Preliminary data from the GENERATE study indicate success of remote alternatives for pancreatic cancer genetic testing and education, with genetic testing uptake rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for pancreatic cancer interception.

Prior small reports have postulated a link between gastrointestinal polyposis and childhood and young adulthood cancer (CYAC) treatment (therapy-associated polyposis; TAP), but this remains a poorly understood phenomenon. The aim of this study was to describe the phenotypic spectrum of TAP in a multi-institutional cohort. TAP cases were identified from eight high-risk cancer centers. Cases were defined as patients with ≥10 gastrointestinal polyps without known causative germline alteration or hereditary colorectal cancer predisposition syndrome who had a history of prior treatment with chemotherapy and/or radiotherapy for CYAC. A total of 34 TAP cases were included (original CYAC: 27 Hodgkin lymphoma, three neuroblastoma, one acute myeloid leukemia, one medulloblastoma, one nephroblastoma, and one non-Hodgkin lymphoma). Gastrointestinal polyposis was first detected at a median of 27 years (interquartile range, 20–33) after CYAC treatment. A total of 12 of 34 (35%) TAP cases had ≥50 colorectal polyps. A total of 32 of 34 (94%) had >1 histologic polyp type. A total of 25 of 34 (74%) had clinical features suggestive of ≥1 colorectal cancer predisposition syndrome [e.g., attenuated familial adenomatous polyposis (FAP), serrated polyposis syndrome, extracolonic manifestations of FAP, mismatch repair–deficient colorectal cancer, or hamartomatous polyposis] including 8 of 34 (24%) with features of multiple such syndromes. TAP is an apparently acquired phenomenon that should be considered in patients who develop significant polyposis without known causative germline alteration but who have had prior treatment for a CYAC. Patients with TAP have features that may mimic various hereditary colorectal cancer syndromes, suggesting multiple concurrent biologic mechanisms, and recognition of this diagnosis may have implications for cancer risk and screening.

Supplementary Table 3 shows types of surgical resection

Socioeconomic background questionnaire

Supplementary Table 2 shows individual case-level data (clinical history, genetic testing, secondary cancers)

Storyboard for Arm 1

Table of Demographic and Socioeconomic characteristics

BACKGROUND: COVID-19 pandemic-related disruptions to EUS-based pancreatic cancer surveillance in high-risk individuals remain uncertain. METHODS: Analysis of enrolled participants in the CAPS5 Study, a prospective multicenter study of pancreatic cancer surveillance in high-risk individuals. RESULTS: Amongst 693 enrolled high-risk individuals under active surveillance, 108 (16%) had an EUS scheduled during the COVID-19 pandemic-related shutdown (median length of 78 days) in the spring of 2020, with 97% of these procedures being canceled. Of these canceled surveillance EUSs, 83% were rescheduled in a median of 4.1 months, however 17% were not rescheduled after 6 months follow-up. Prior history of cancer was associated with increased likelihood of rescheduling. To date no pancreatic cancer has been diagnosed among those whose surveillance was delayed. CONCLUSIONS: COVID-19 delayed pancreatic cancer surveillance with no adverse outcomes in efficiently rescheduled individuals. However, 1 in 6 high-risk individuals had not rescheduled surveillance, indicating the need for vigilance to ensure timely surveillance rescheduling.

Lynch syndrome (LS) is the most common inherited cause of colorectal and endometrial cancers. Identifying individuals at risk for LS without personal cancer history requires detailed collection and assessment of family health history. However, barriers exist to family health history collection, especially in historically underserved populations. To improve LS risk assessment in historically underserved populations, we adapted the provider-facing PREdiction Model for gene Mutations (PREMM5™ model), a validated LS risk assessment model, into a patient-facing electronic application through an iterative development process involving expert and patient stakeholders. We report on preliminary findings based on the first 500 individuals exposed to the adapted application in a primary care population enriched for low-literacy and low-resource patients. Major adaptations to the PREMM5™ provider module included reduction in reading level, addition of interactive literacy aids, incorporation of family history assessment for both maternal and paternal sides of the family, and inclusion of questions about individual relatives or small groups of relatives to reduce cognitive burden. In the first 500 individuals, 90% completed the PREMM5™ independently; of those, 94% did so in 5 min or less (ranged from 0.2 to 48.8 min). The patient-facing application was able to accurately classify 84% of patients as having clinically significant or not clinically significant LS risk. Our preliminary results suggest that in this diverse study population, most participants were able to rapidly, accurately, and independently complete an interactive application collecting family health history assessment that accurately assessed for Lynch syndrome risk.

Juvenile polyposis syndrome (JPS) is a clinically diagnosed hamartomatous polyposis syndrome that increases the risk of gastrointestinal cancer. Approximately 40%–50% of JPS is caused by a germline disease-causing variant (DCV) in the SMAD4 or BMPR1A genes. The aim of this study was to characterize the phenotype of DCV-negative JPS and compare it with DCV-positive JPS. Herein, we analyzed a cohort of 145 individuals with JPS from nine institutions, including both pediatric and adult centers. Data analyzed included age at diagnosis, family history, cancer history, need for colectomy/gastrectomy, and polyp number and location. Compared with DCV-positive JPS, DCV-negative JPS was associated with younger age at diagnosis (P < 0.001), lower likelihood of having a family history of JPS (P < 0.001), and a lower risk of colectomy (P = 0.032). None of the DCV-negative individuals had gastric or duodenal polyps, and polyp burden decreased after the first decade compared with DCV-positive JPS. Subgroup analysis between SMAD4 and BMPR1A carriers showed that SMAD4 carriers were more likely to have a family history of JPS and required gastrectomy. Taken together, these data provide the largest phenotypic characterization of individuals with DCV-negative JPS to date, showing that this group has distinct differences compared with JPS due to a SMAD4 or BMPR1A variant. Better understanding of phenotype and cancer risk associated with JPS both with and without a DCV may ultimately allow for individualized management of polyposis and cancer risk. Prevention Relevance: Juvenile Polyposis Syndrome (JPS) is a gastrointestinal cancer predisposition syndrome requiring lifelong surveillance, however there is limited data comparing individuals with and without a germline disease-causing variant in SMAD4 or BMPR1A. Herein we show that individuals with JPS without an underlying disease-causing variant have distinct phenotypic differences including lack of upper gastrointestinal polyps and lower rates of a family history of JPS, suggesting that a different approach to management may be appropriate in this population.

Models used to predict the probability of an individual having a pathogenic homozygous or heterozygous variant in a mismatch repair gene, such as MMRpro, are widely used. Recently, MMRpro was updated with new colorectal cancer penetrance estimates. The purpose of this study was to evaluate the predictive performance of MMRpro and other models for individuals with a family history of colorectal cancer.We performed a validation study of 4 models, Leiden, MMRpredict, PREMMMMRpro with additional tumor information (MMRpro+) and PREMMMMRpro+ and PREMM

PURPOSE Tumor testing for microsatellite instability and/or mismatch repair-deficiency (MSI/IHC) and clinical prediction models effectively screen for Lynch syndrome (LS)–associated colorectal cancer (CRC) and endometrial cancer (EC), but they have not been assessed for their ability to identify non-LS forms of inherited risk. The aim of this study was to compare MSI/IHC and the PREMM5 prediction model to identify carriers of LS and non-LS pathogenic variants (PVs) among patients with CRC and EC. PATIENTS AND METHODS Data were retrospectively analyzed from two single-institution cohorts: 706 patients with CRC and/or EC referred for genetic evaluation/testing (high-risk cohort) and 1,058 consecutively ascertained patients with CRC (oncology clinic cohort), unselected for familial risk. All participants underwent germline multigene panel testing. PREMM5 scores were calculated from personal/family cancer history. The primary outcome was the proportion of individuals with germline PVs (LS PVs, high-penetrance PVs, and any PVs) who had abnormal MSI/IHC testing and/or PREMM5 score ≥ 2.5%. RESULTS MSI/IHC and PREMM5 had comparable sensitivity for identifying LS carriers in high-risk (89.3% v 85.7%; P = .712) and oncology clinic patients (96.6% v 96.6%; P = 1.000), although MSI/IHC had significantly superior specificity for LS (81.3% v 20.1%; P < .001; 92.3% v 24.3%; P < .001). In both cohorts, PREMM5 had superior sensitivity to MSI/IHC at identifying patients with any high-penetrance PVs and any low-, moderate-, and high-penetrance PVs. Among patients with normal MSI/IHC, PREMM5 identified 84.2% and 83.3% of high-risk patients with CRC/EC and oncology clinic CRC patients with high-penetrance PVs, respectively. CONCLUSION MSI/IHC and PREMM5 effectively identify patients with CRC and/or EC with LS, although MSI/IHC has better specificity for LS. Because PREMM5 identifies non-LS, high-penetrance germline PVs, patients with CRC and/or EC with PREMM5 score ≥ 2.5%, including those with normal MSI/IHC, should be offered multigene panel testing.

BACKGROUND: Mismatch repair (MMR) deficiency is the hallmark of tumours from Lynch syndrome (LS), sporadic MLH1 hypermethylated and Lynch-like syndrome (LLS), but there is a lack of understanding of the variability in their mutational profiles based on clinical phenotypes. The aim of this study was to perform a molecular characterisation to identify novel features that can impact tumour behaviour and clinical management. METHODS: We tested 105 MMR-deficient colorectal cancer tumours (25 LS, 35 LLS and 45 sporadic) for global exome microsatellite instability, cancer mutational signatures, mutational spectrum and neoepitope load. RESULTS: Fifty-three percent of tumours showed high contribution of MMR-deficient mutational signatures, high level of global exome microsatellite instability, loss of MLH1/PMS2 protein expression and included sporadic tumours. Thirty-one percent of tumours showed weaker features of MMR deficiency, 62% lost MSH2/MSH6 expression and included 60% of LS and 44% of LLS tumours. Remarkably, 9% of all tumours lacked global exome microsatellite instability. Lastly, HLA-B07:02 could be triggering the neoantigen presentation in tumours that show the strongest contribution of MMR-deficient tumours. CONCLUSIONS: Next-generation sequencing approaches allow for a granular molecular characterisation of MMR-deficient tumours, which can be essential to properly diagnose and treat patients with these tumours in the setting of personalised medicine.

PURPOSE An inherited basis for presumed sporadic neuroendocrine tumor (NET) has been suggested by evidence of familial clustering of NET and a higher incidence of second malignancies in patients and families with NET. To further investigate a potential heritable basis for sporadic neuroendocrine tumors, we performed multigene platform germline analysis to determine the frequency of hereditary susceptibility gene variants in a cohort of patients with sporadic small intestine NET (SI-NET). METHODS We performed a multigene platform germline analysis with Invitae's 83-gene, next-generation sequencing panel using DNA from 88 individuals with SI-NET from a clinically annotated database of patients with NET evaluated at Dana-Farber Cancer Institute (DFCI) who are considered high risk for inherited variants. Additionally, we evaluated the prevalence of pathogenic variants in an unselected cohort of patients with SI-NET who underwent testing with Invitae. RESULTS Of the 88 patients in the DFCI cohort, a pathogenic germline variant was identified in eight (9%) patients. In an independent cohort of 120 patients with SI-NET, a pathogenic germline variant was identified in 13 (11%) patients. Pathogenic variants were identified in more than one patient in the following genes: ATM, RAD51C, MUTYH, and BLM. Somatic testing of tumors from the DFCI cohort was suboptimal because of insufficient coverage of all targeted exons, and therefore, analysis was limited. CONCLUSION We demonstrate a 9%-11% incidence of pathogenic germline variants in genes associated with inherited susceptibility for malignancy not previously described in association with SI-NET. The association of these germline variants with neuroendocrine carcinogenesis and risk is uncertain but warrants further characterization.

This study aimed to evaluate the laboratory-related outcomes of participants who were offered genomic testing based on cancer family history risk assessment tools.Patients from clinics that serve populations with access barriers, who are screened at risk for a hereditary cancer syndrome based on adapted family history collection tools (the Breast Cancer Genetics Referral Screening Tool and PREMMOf all the participants, 87% successfully returned a saliva kit. Overall, 5% had a pathogenic/likely pathogenic cancer risk variant and 1% had a secondary finding. Almost all (14/15, 93%) participants completed recommended consultations with nongenetics providers after an average of 17 months. The recommended actions (eg, breast magnetic resonance imaging) were completed by 17 of 25 participants. Participant personal history of cancer and PREMMThis accessible model of hereditary cancer risk assessment and genetic testing yielded results that were often acted upon by patients and physicians.

Funder: Victorian Cancer Agency, Funder: NIHR Manchester Biomedical Research Centre, Funder: Cancer Research UK, Funder: Cancer Council Tasmania, Funder: Instituto de Salud Carlos III, Funder: Cancer Australia, Funder: NIHR Oxford Biomedical Research Centre, Funder: Fundación Científica de la Asociación Española Contra el Cáncer, Funder: Cancer Council South Australia, Funder: Swedish Cancer Society, Funder: NIHR Cambridge Biomedical Research Centre, Funder: Institut Català de la Salut, Funder: Cancer Council Victoria, Funder: Prostate Cancer Foundation of Australia, Funder: National Institutes of Health, BACKGROUND: Lynch syndrome is a rare familial cancer syndrome caused by pathogenic variants in the mismatch repair genes MLH1, MSH2, MSH6, or PMS2, that cause predisposition to various cancers, predominantly colorectal and endometrial cancer. Data are emerging that pathogenic variants in mismatch repair genes increase the risk of early-onset aggressive prostate cancer. The IMPACT study is prospectively assessing prostate-specific antigen (PSA) screening in men with germline mismatch repair pathogenic variants. Here, we report the usefulness of PSA screening, prostate cancer incidence, and tumour characteristics after the first screening round in men with and without these germline pathogenic variants. METHODS: The IMPACT study is an international, prospective study. Men aged 40-69 years without a previous prostate cancer diagnosis and with a known germline pathogenic variant in the MLH1, MSH2, or MSH6 gene, and age-matched male controls who tested negative for a familial pathogenic variant in these genes were recruited from 34 genetic and urology clinics in eight countries, and underwent a baseline PSA screening. Men who had a PSA level higher than 3·0 ng/mL were offered a transrectal, ultrasound-guided, prostate biopsy and a histopathological analysis was done. All participants are undergoing a minimum of 5 years' annual screening. The primary endpoint was to determine the incidence, stage, and pathology of screening-detected prostate cancer in carriers of pathogenic variants compared with non-carrier controls. We used Fisher's exact test to compare the number of cases, cancer incidence, and positive predictive values of the PSA cutoff and biopsy between carriers and non-carriers and the differences between disease types (ie, cancer vs no cancer, clinically significant cancer vs no cancer). We assessed screening outcomes and tumour characteristics by pathogenic variant status. Here we present results from the first round of PSA screening in the IMPACT study. This study is registered with ClinicalTrials.gov, NCT00261456, and is now closed to accrual. FINDINGS: Between Sept 28, 2012, and March 1, 2020, 828 men were recruited (644 carriers of mismatch repair pathogenic variants [204 carriers of MLH1, 305 carriers of MSH2, and 135 carriers of MSH6] and 184 non-carrier controls [65 non-carriers of MLH1, 76 non-carriers of MSH2, and 43 non-carriers of MSH6]), and in order to boost the sample size for the non-carrier control groups, we randomly selected 134 non-carriers from the BRCA1 and BRCA2 cohort of the IMPACT study, who were included in all three non-carrier cohorts. Men were predominantly of European ancestry (899 [93%] of 953 with available data), with a mean age of 52·8 years (SD 8·3). Within the first screening round, 56 (6%) men had a PSA concentration of more than 3·0 ng/mL and 35 (4%) biopsies were done. The overall incidence of prostate cancer was 1·9% (18 of 962; 95% CI 1·1-2·9). The incidence among MSH2 carriers was 4·3% (13 of 305; 95% CI 2·3-7·2), MSH2 non-carrier controls was 0·5% (one of 210; 0·0-2·6), MSH6 carriers was 3·0% (four of 135; 0·8-7·4), and none were detected among the MLH1 carriers, MLH1 non-carrier controls, and MSH6 non-carrier controls. Prostate cancer incidence, using a PSA threshold of higher than 3·0 ng/mL, was higher in MSH2 carriers than in MSH2 non-carrier controls (4·3% vs 0·5%; p=0·011) and MSH6 carriers than MSH6 non-carrier controls (3·0% vs 0%; p=0·034). The overall positive predictive value of biopsy using a PSA threshold of 3·0 ng/mL was 51·4% (95% CI 34·0-68·6), and the overall positive predictive value of a PSA threshold of 3·0 ng/mL was 32·1% (20·3-46·0). INTERPRETATION: After the first screening round, carriers of MSH2 and MSH6 pathogenic variants had a higher incidence of prostate cancer compared with age-matched non-carrier controls. These findings support the use of targeted PSA screening in these men to identify those with clinically significant prostate cancer. Further annual screening rounds will need to confirm these findings. FUNDING: Cancer Research UK, The Ronald and Rita McAulay Foundation, the National Institute for Health Research support to Biomedical Research Centres (The Institute of Cancer Research and Royal Marsden NHS Foundation Trust; Oxford; Manchester and the Cambridge Clinical Research Centre), Mr and Mrs Jack Baker, the Cancer Council of Tasmania, Cancer Australia, Prostate Cancer Foundation of Australia, Cancer Council of Victoria, Cancer Council of South Australia, the Victorian Cancer Agency, Cancer Australia, Prostate Cancer Foundation of Australia, Asociación Española Contra el Cáncer (AECC), the Instituto de Salud Carlos III, Fondo Europeo de Desarrollo Regional (FEDER), the Institut Català de la Salut, Autonomous Government of Catalonia, Fundação para a Ciência e a Tecnologia, National Institutes of Health National Cancer Institute, Swedish Cancer Society, General Hospital in Malmö Foundation for Combating Cancer.

Background: Uptake of genetic testing for cancer susceptibility in family members of cancer patients is suboptimal. The GENetic Education, Risk Assessment, and TEsting (GENERATE) study evaluated two strategies of remote genetic education and testing in relatives of pancreatic ductal adenocarcinoma (PDAC) patients. Methods: Eligible participants had: a first-degree relative with PDAC or had a known pathogenic germline variant (PGV) in one of thirteen PDAC predisposition genes (APC, ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, or TP53) and a first- or second-degree relative with PDAC. Participants were cluster-randomized by family into one of two arms. Arm 1 included an interactive telemedicine session with a genetic counselor, followed by genetic testing at a commercial laboratory. Arm 2 involved remote online genetic education and testing at the commercial laboratory without the interactive session. The primary outcome was uptake of genetic testing across study arms, which was compared by permutation tests and mixed-effects logistic regression models. Results: Between 5/8/2019 and 6/1/2021, 424 families were randomized, including 601 participants (n=296 Arm 1; n=305 Arm 2). The uptake of genetic testing was 87% (257/296) in Arm 1 and 93% (284/305) in Arm 2 (p=0.014). Participants in Arm 1 were significantly less likely to obtain genetic testing compared to Arm 2 (Adjusted ratio [Arm1/Arm2] 0.90, 95% confidence interval 0.78-0.98). BRCA2, ATM, CDKN2A and PALB2 were the most common PDAC susceptibility genes in which PGVs were identified. Conclusions: Remote methods of genetic education and testing are successful alternatives to traditional germline susceptibility testing. Citation Format: Nicolette J. Rodriguez, C. Sloane Furniss, Matthew B. Yurgelun, Chinedu Ukaegbu, Pamela E. Constantinou, Ileana Fortes, Alyson Caruso, Alison N. Schwartz, Jill E. Stopfer, Meghan Underhill-Blazey, Barbara Kenner, Scott H. Nelson, Sydney Okumura, Alicia Y. Zhou, Tara B. Coffin, Hajime Uno, Miki Horiguchi, Allyson J. Ocean, Florencia McAllister, Andrew M. Lowy, Scott M. Lippman, Alison P. Klein, Lisa Madlensky, Gloria M. Petersen, Judy E. Garber, Michael G. Goggins, Anirban Maitra, Sapna Syngal. A randomized study of two Strategies of remote Genetic Education, Risk Assessment, and Testing (GENERATE) for family members of patients with pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A029.

BackgroundMismatch repair (MMR) deficiency is the hallmark of tumors from Lynch syndrome (LS), sporadic MLH1 hypermethylated, and Lynch-like syndrome (LLS), but there is a lack of understanding of the variability in their mutational profiles based on clinical phenotypes. The aim of this study was to perform a molecular characterization to identify novel features that can impact tumor behavior and clinical management.MethodsWe tested 105 MMR-deficient colorectal cancer tumors (25 LS, 35 LLS, and 45 sporadic) for global exome microsatellite instability, cancer mutational signatures, mutational spectrum and neoepitope load.Results78% of tumors showed high contribution of MMR-deficient mutational signatures, high level of global exome microsatellite instability, loss of MLH1/PMS2 protein expression and included sporadic tumors. 22% of tumors showed weaker features of MMR deficiency, 73% lost MSH2/MSH6 expression and included half of LS and LLS tumors. Remarkably, 9% of all tumors lacked global exome microsatellite instability. Lastly, HLA-B07:02 could be triggering the neoantigen presentation in tumors that show the strongest contribution of MMR-deficient tumors.ConclusionsNext-generation sequencing approaches allow for a granular molecular characterization of MMR-deficient tumors, which can be essential to properly diagnose and treat patients with these tumors in the setting of personalized medicine.

IMPORTANCE: Pathogenic germline variants in the ATM gene have been associated with pancreatic cancer risk. Although genetic testing identifies these variants in approximately 1% to 3% of unselected patients with pancreatic cancer, the lifetime risk of pancreatic cancer among individuals with pathogenic ATM variants has not been well estimated. OBJECTIVE: To estimate age-specific penetrance of pancreatic cancer in individuals with a pathogenic variant in the ATM gene. DESIGN, SETTING, AND PARTICIPANTS: This was a multicenter cohort study of pancreatic cancer family registries in the US and Canada using pedigree data from 130 pancreatic cancer kindreds with a pathogenic germline ATM variant. Data analyses were performed from January 2020 to February 2021. MAIN OUTCOMES AND MEASURES: Observational age-specific risk of pancreatic cancer. Penetrance was estimated using modified segregation analysis. RESULTS: The study population of 130 families (123 [95%] White families) comprised 2227 family members (mean age [SD], 58 [22] years; 1096 [49%] women) with complete records (ie, including familial relationships, pancreatic cancer diagnosis, ATM status, proband status, and age), of which 155 individuals had positive results for an ATM pathogenic variant, 16 had a negative result, and the remainder did not have a test result. In these 130 families, 217 individuals had pancreatic cancer: 78 families had 1 such member; 34 families had 2 such members; and 18 families had 3 or more members with pancreatic cancer. The average (range) age at diagnosis was 64 (31-98) years. The cumulative risk of pancreatic cancer among individuals with a germline pathogenic ATM variant was estimated to be 1.1% (95% CI, 0.8%-1.3%) by age 50 years; 6.3% (95% CI, 3.9%-8.7%) by age 70 years; and 9.5% (95% CI, 5.0%-14.0%) by age 80 years. Overall, the relative risk of pancreatic cancer was 6.5 (95% CI, 4.5-9.5) in ATM variant carriers compared with noncarriers. CONCLUSIONS AND RELEVANCE: This multicenter cohort study found that individuals with a germline pathogenic ATM variant were at an increased lifetime risk of pancreatic cancer. These risk estimates can help guide decision-making when evaluating the risks and benefits of enhanced early detection surveillance.

PURPOSE: National guidelines recommend genetic counseling and multigene germline testing (GC/MGT) for all patients with pancreatic ductal adenocarcinoma (PDAC). This study's aim was to assess real-world effectiveness of implementing systematic GC/MGT for all patients with PDAC at a high-volume academic institution. METHODS: An iterative process for systematizing GC/MGT was developed in which gastrointestinal oncology providers at the Dana-Farber Cancer Institute were recommended to refer all patients with PDAC for GC/MGT (clinician-directed referral). Workflows were subsequently changed such that patients with PDAC were automatically offered GC/MGT when scheduling their initial oncology consultation (automated referral). Clinical and germline data were collected on a consecutive cohort of patients with PDAC undergoing GC/MGT during a 25-month enrollment period (19-month clinician-directed referrals; 6-month automated referrals). RESULTS: One thousand two hundred fourteen patients with PDAC were seen for initial oncologic evaluation, 266 (21.9%) of whom underwent GC/MGT. Compared with baseline clinician-directed referrals, implementation of automated referrals led to a significant increase in patients with PDAC undergoing GC/MGT (16.5% v 38.0%, P < .001), including those undergoing multigene germline testing (MGT) ≤ 7 days of initial oncology evaluation (14.7% v 60.3%, P < .001), with preserved pathogenic variant detection rates (10.0% v 11.2%, P = 0.84). 16 of 28 (57.1%) pathogenic variant carriers had relatives who pursued cascade germline testing, and 13 of 26 (50.0%) carriers with incurable disease received targeted therapy based on MGT results. CONCLUSION: Implementation of systematic GC/MGT in patients with PDAC is feasible and leads to management changes for patients with PDAC and their families. GC/MGT workflows that bypass the need for clinician referral result in superior uptake and time to testing. Further investigation is needed to identify other barriers and facilitators of universal GC/MGT.

10503 Background: Lynch syndrome (LS) is the most common inherited cause of colorectal (CRC) and endometrial cancers. Significant provider and institutional level barriers limit LS detection, even in oncology patients with LS-associated cancers. PREMM5 is a validated tool based on personal and family cancer history that is recommended by national professional societies for LS risk assessment. This project’s goal was to study the feasibility of patient-facing LS risk assessment using a PREMM5 screener embedded in an electronic health record (EHR) system, as a means of improving LS identification. Methods: The PREMM5 LS screener intake questions were adapted to be completed by patients rather than healthcare providers. Screener adaptation and implementation involved iterative review by multidisciplinary experts and multilevel stakeholder engagement. The patient-facing PREMM5 LS screener was embedded in the EHR (Epic) at the Dana-Farber Cancer Institute (DFCI) to enable remote (via the EHR patient portal) and on-site completion (in clinic waiting rooms). All new gastrointestinal (GI) cancer patients seen at DFCI for initial oncology consultation from 6/2020-12/2021 were invited through the portal to complete the screener. PREMM5 scores ≥2.5% were considered “positive”, with genetics referral recommended. Beginning 2/2021, the EHR generated an automated provider-facing alert for positive screens. Results: 35% (1504/4262) of new GI cancer patients completed the screener. 367/1504 (24%) had a positive PREMM5 screen (mean age 53 years), of whom 66% were male, and 62%, 12% and 10% had CRC, neuroendocrine and pancreas cancer respectively. 97% (357/367) of screen positives completed the PREMM5 screener remotely through the portal. 102/367 (28%) received a genetics referral as a result of their positive PREMM5 screen (not including 75 genetics referrals outside this workflow), 13 of whom had a pathogenic variant (PV) on germline testing, including 4 with LS ( MSH2, MSH6, PMS2), and others with PVs in ATM, BRCA2, CHEK2, NTHL1, RAD50 and RECQL4. Conclusions: A practice-wide patient-facing EHR-integrated PREMM5 risk assessment workflow is feasible and identified nearly 1 in 4 general GI oncology patients as warranting genetic evaluation, resulting in the identification of numerous actionable germline PVs. This method of deployment could make genetic risk assessment more accessible to non-genetics providers. The suboptimal screener completion rate and 28% genetics referral rate among positive screens suggest the need for additional refinements, including patient and provider engagement and outreach to positive screens who do not follow up with appointments for genetic evaluation.

Up to 10% of patients with pancreatic ductal adenocarcinoma (PDAC) carry underlying germline pathogenic variants in cancer susceptibility genes. The GENetic Education Risk Assessment and TEsting (GENERATE) study aimed to evaluate novel methods of genetic education and testing in relatives of patients with PDAC. Eligible individuals had a family history of PDAC and a relative with a germline pathogenic variant in APC, ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, or TP53 genes. Participants were recruited at six academic cancer centers and through social media campaigns and patient advocacy efforts. Enrollment occurred via the study website (https://GENERATEstudy.org) and all participation, including collecting a saliva sample for genetic testing, could be done from home. Participants were randomized to one of two remote methods that delivered genetic education about the risks of inherited PDAC and strategies for surveillance. The primary outcome of the study was uptake of genetic testing. From 5/8/2019 to 5/6/2020, 49 participants were randomized to each of the intervention arms. Overall, 90 of 98 (92%) of randomized participants completed genetic testing. The most frequently detected pathogenic variants included those in BRCA2 (N = 15, 17%), ATM (N = 11, 12%), and CDKN2A (N = 4, 4%). Participation in the study remained steady throughout the onset of the Coronavirus disease (COVID-19) pandemic. Preliminary data from the GENERATE study indicate success of remote alternatives to traditional cascade testing, with genetic testing rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for PDAC interception approaches. Prevention Relevance: Preliminary data from the GENERATE study indicate success of remote alternatives for pancreatic cancer genetic testing and education, with genetic testing uptake rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for pancreatic cancer interception.

Lynch syndrome (LS) is the most common inherited cause of colorectal and endometrial cancers. Identifying individuals at risk for LS without personal cancer history requires detailed collection and assessment of family health history. However, barriers exist to family health history collection, especially in historically underserved populations. To improve LS risk assessment in historically underserved populations, we adapted the provider-facing PREdiction Model for gene Mutations (PREMM

PURPOSE: Tumor testing for microsatellite instability and/or mismatch repair-deficiency (MSI/IHC) and clinical prediction models effectively screen for Lynch syndrome (LS)–associated colorectal cancer (CRC) and endometrial cancer (EC), but they have not been assessed for their ability to identify non-LS forms of inherited risk. The aim of this study was to compare MSI/IHC and the PREMM(5) prediction model to identify carriers of LS and non-LS pathogenic variants (PVs) among patients with CRC and EC. PATIENTS AND METHODS: Data were retrospectively analyzed from two single-institution cohorts: 706 patients with CRC and/or EC referred for genetic evaluation/testing (high-risk cohort) and 1,058 consecutively ascertained patients with CRC (oncology clinic cohort), unselected for familial risk. All participants underwent germline multigene panel testing. PREMM(5) scores were calculated from personal/family cancer history. The primary outcome was the proportion of individuals with germline PVs (LS PVs, high-penetrance PVs, and any PVs) who had abnormal MSI/IHC testing and/or PREMM(5) score ≥ 2.5%. RESULTS: MSI/IHC and PREMM(5) had comparable sensitivity for identifying LS carriers in high-risk (89.3% v 85.7%; P = .712) and oncology clinic patients (96.6% v 96.6%; P = 1.000), although MSI/IHC had significantly superior specificity for LS (81.3% v 20.1%; P < .001; 92.3% v 24.3%; P < .001). In both cohorts, PREMM(5) had superior sensitivity to MSI/IHC at identifying patients with any high-penetrance PVs and any low-, moderate-, and high-penetrance PVs. Among patients with normal MSI/IHC, PREMM(5) identified 84.2% and 83.3% of high-risk patients with CRC/EC and oncology clinic CRC patients with high-penetrance PVs, respectively. CONCLUSION: MSI/IHC and PREMM(5) effectively identify patients with CRC and/or EC with LS, although MSI/IHC has better specificity for LS. Because PREMM(5) identifies non-LS, high-penetrance germline PVs, patients with CRC and/or EC with PREMM(5) score ≥ 2.5%, including those with normal MSI/IHC, should be offered multigene panel testing.

Juvenile polyposis syndrome (JPS) is a clinically diagnosed hamartomatous polyposis syndrome that increases the risk of gastrointestinal cancer. Approximately 40–50% of JPS is caused by a germline disease-causing variant (DCV) in the SMAD4 or BMPR1A genes. The aim of this study is to characterize the phenotype of DCV-negative JPS and compare it to DCV-positive JPS. Herein we analyze a cohort of 145 individuals with JPS from nine institutions, including both pediatric and adult centers. Data analyzed included age at diagnosis, family history, cancer history, need for colectomy/gastrectomy, and polyp number and location. Compared to DCV-positive JPS, DCV-negative JPS was associated with younger age at diagnosis (p

BACKGROUND: Germline variants in the APC and MUTYH genes contribute to colorectal cancer (CRC) and adenoma risk, though may occur with varying frequencies in individuals of different ancestries. The aim of this study was to evaluate the prevalence of APC, monoallelic MUTYH and biallelic MUTYH germline variants in Ashkenazi Jewish (AJ) and Other Ancestry (OA) individuals with colorectal adenomas. METHODS: We studied 7,225 individuals with colorectal adenomas who had germline APC and MUTYH testing at a commercial laboratory. Cross-sectional medical history data were extracted from provider-completed test requisition forms. We performed bivariate analysis to compare the frequency of APC and MUTYH variants between AJ and OA, and examined APC p.I1307K and monoallelic MUTYH carrier phenotypes using logistic regression. RESULTS: Pathogenic APC variants occurred in 38/285 AJ (13%) and 1342/6940 OA (19%; P=0.09); biallelic MUTYH variants in 2/285 (1%) AJ and 399/6940 (6%) OA (P

OBJECTIVES: The aim of this study was to quantify the impact of predictor measurement heterogeneity on prediction model performance. Predictor measurement heterogeneity refers to variation in the measurement of predictor(s) between the derivation of a prediction model and its validation or application. It arises, for instance, when predictors are measured using different measurement instruments or protocols. STUDY DESIGN AND SETTING: We examined the effects of various scenarios of predictor measurement heterogeneity in real-world clinical examples using previously developed prediction models for diagnosis of ovarian cancer, mutation carriers for Lynch syndrome, and intrauterine pregnancy. RESULTS: Changing the measurement procedure of a predictor influenced the performance at validation of the prediction models in nine clinical examples. Notably, it induced model miscalibration. The calibration intercept at validation ranged from -0.70 to 1.43 (0 for good calibration), whereas the calibration slope ranged from 0.50 to 1.67 (1 for good calibration). The difference in C-statistic and scaled Brier score between derivation and validation ranged from -0.08 to +0.08 and from -0.40 to +0.16, respectively. CONCLUSION: This study illustrates that predictor measurement heterogeneity can influence the performance of a prediction model substantially, underlining that predictor measurements used in research settings should resemble clinical practice. Specification of measurement heterogeneity can help researchers explaining discrepancies in predictive performance between derivation and validation setting. ispartof: JOURNAL OF CLINICAL EPIDEMIOLOGY vol:119 pages:7-18 ispartof: location:United States status: published

Background: Roughly 7–10% of patients with pancreatic ductal adenocarcinoma (PDAC) have a deleterious germline variant. Although identification of germline variants in family members has implications for cancer surveillance and can lead to early cancer detection and interception for PDAC, as well as other cancers, cascade genetic testing rates are low. The GENetic Education, Risk Assessment and TEsting (GENERATE) study evaluates novel methods of providing genetic education and testing for individuals at risk for hereditary PDAC. Methods: Eligible participants had: (1) a first- or second-degree relative with a diagnosis of PDAC and a known familial germline variant in APC, ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, or TP53 (Known Familial Mutation (KFM)), (2) or were first-degree relatives of PDAC patients (no KFM). Participants were recruited through six academic centers, patient advocacy organizations and online outreach. Enrollment occurred through the study website (www.GENERATEstudy.org). All study participation, including genetic testing via a at home saliva sample kit, was done remotely. Participants were cluster randomized at the family level into one of two arms. Arm 1 (Doxy.me plus Color Genomics) included remote genetic education and testing through a video-based telemedicine platform (Doxy.me) and physician-mediated testing through Color Genomics. Arm 2 included remote genetic education and testing through Color Genomics only. Results: Between 5/8/2019–6/01/2021, 423 families were randomized, comprising 595 participants. Recruitment occurred through patient invitation via healthcare providers (n=128, 21.5%), family members (n=271, 45.5%), friends, advocacy groups, and online outreach (n=223, 37.5%). Participants were referred from the six GENERATE academic centers (n=270, 45.4%) and other institutions (n=325, 54.6%). Study participants were 52.5 years on average, primarily identified as White (n=577, 97%) and from the Northeast (n=184, 30.9%), Midwest (n=154, 25.9%), South (n=158, 26.6%) and West (n=99, 16.6%). Participants were randomized into each arm (n=296 Doxy.me plus Color Genomics; n=299 Color Genomics only). To date, 527 (88.6%) participants have ordered genetic testing. The uptake of genetic testing was 253/296 (85.5%) in the Doxy.me plus Color Genomics arm and 274/299 (91.6%) in the Color Genomics only arm (p=0.049, generalized mixed-effects model). A total of 82 PDAC associated pathogenic variants were identified. The most frequently detected variants were BRCA2 (n=32), ATM (n=25) and PALB2 (n=6). Additionally, 13 non-PDAC associated pathogenic variants and 20 low penetrance variants were detected. Conclusions: Remote methods of genetic education and testing are successful alternatives to traditional cascade testing, with genetic testing rates nearly 90%. Participant follow up will assess if satisfaction with decision making, cancer-risk distress, knowledge gained, family communication, and uptake of surveillance were impacted by the mode of delivery of pre-test genetic education. Citation Format: Nicolette J. Rodriguez, Constance S. Furniss, Matthew B. Yurgelun, Chinedu Ukaegbu, Pamela E. Constantinou, Alison N. Schwartz, Jill Stopfer, Meghan Underhill-Blazey, Barbara Kenner, Scott Nelson, Sydney Okumura, Sherman Law, Alicia Y. Zhou, Tara B. Coffin, Hajime Uno, Allyson Ocean, Florencia McAllister, Andrew M. Lowy, Scott M. Lippman, Alison P. Klein, Lisa Madlensky, Gloria M. Petersen, Judy E. Garber, Michael G. Goggins, Anirban Maitra, Sapna Syngal. Comparison of novel healthcare delivery models on the uptake of genetic education and testing in families with a history of pancreatic cancer: The GENetic Education, Risk Assessment and TEsting (GENERATE) study [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-013.

Purpose Current Lynch syndrome (LS) prediction models quantify the risk to an individual of carrying a pathogenic germline mutation in three mismatch repair (MMR) genes: MLH1, MSH2, and MSH6. We developed a new prediction model, PREMM5, that incorporates the genes PMS2 and EPCAM to provide comprehensive LS risk assessment. Patients and Methods PREMM5 was developed to predict the likelihood of a mutation in any of the LS genes by using polytomous logistic regression analysis of clinical and germline data from 18,734 individuals who were tested for all five genes. Predictors of mutation status included sex, age at genetic testing, and proband and family cancer histories. Discrimination was evaluated by the area under the receiver operating characteristic curve (AUC), and clinical impact was determined by decision curve analysis; comparisons were made to the existing PREMM1,2,6 model. External validation of PREMM5 was performed in a clinic-based cohort of 1,058 patients with colorectal cancer. Results Pathogenic mutations were detected in 1,000 (5%) of 18,734 patients in the development cohort; mutations included MLH1 (n = 306), MSH2 (n = 354), MSH6 (n = 177), PMS2 (n = 141), and EPCAM (n = 22). PREMM5 distinguished carriers from noncarriers with an AUC of 0.81 (95% CI, 0.79 to 0.82), and performance was similar in the validation cohort (AUC, 0.83; 95% CI, 0.75 to 0.92). Prediction was more difficult for PMS2 mutations (AUC, 0.64; 95% CI, 0.60 to 0.68) than for other genes. Performance characteristics of PREMM5 exceeded those of PREMM1,2,6. Decision curve analysis supported germline LS testing for PREMM5 scores ≥ 2.5%. Conclusion PREMM5 provides comprehensive risk estimation of all five LS genes and supports LS genetic testing for individuals with scores ≥ 2.5%. At this threshold, PREMM5 provides performance that is superior to the existing PREMM1,2,6 model in the identification of carriers of LS, including those with weaker phenotypes and individuals unaffected by cancer.

Purpose Hereditary factors play an important role in colorectal cancer (CRC) risk, yet the prevalence of germline cancer susceptibility gene mutations in patients with CRC unselected for high-risk features (eg, early age at diagnosis, personal/family history of cancer or polyps, tumor microsatellite instability [MSI], mismatch repair [MMR] deficiency) is unknown. Patients and Methods We recruited 1,058 participants who received CRC care in a clinic-based setting without preselection for age at diagnosis, personal/family history, or MSI/MMR results. All participants underwent germline testing for mutations in 25 genes associated with inherited cancer risk. Each gene was categorized as high penetrance or moderate penetrance on the basis of published estimates of the lifetime cancer risks conferred by pathogenic germline mutations in that gene. Results One hundred five (9.9%; 95% CI, 8.2% to 11.9%) of 1,058 participants carried one or more pathogenic mutations, including 33 (3.1%) with Lynch syndrome (LS). Twenty-eight (96.6%) of 29 available LS CRCs demonstrated abnormal MSI/MMR results. Seventy-four (7.0%) of 1,058 participants carried non-LS gene mutations, including 23 (2.2%) with mutations in high-penetrance genes (five APC, three biallelic MUTYH, 11 BRCA1/2, two PALB2, one CDKN2A, and one TP53), 15 of whom lacked clinical histories suggestive of their underlying mutation. Thirty-eight (3.6%) participants had moderate-penetrance CRC risk gene mutations (19 monoallelic MUTYH, 17 APC*I1307K, two CHEK2). Neither proband age at CRC diagnosis, family history of CRC, nor personal history of other cancers significantly predicted the presence of pathogenic mutations in non-LS genes. Conclusion Germline cancer susceptibility gene mutations are carried by 9.9% of patients with CRC. MSI/MMR testing reliably identifies LS probands, although 7.0% of patients with CRC carry non-LS mutations, including 1.0% with BRCA1/2 mutations.

Background & Aims Lynch syndrome (LS) is associated with increased risks of various gastrointestinal, gynecologic, genitourinary, and other cancers. Many clinical practice guidelines recommend that LS carriers' screening strategies be devised based on their family history of various cancers, in addition to age-, sex-, and gene-specific considerations. The aim of this study was to examine the association between family history and other clinical factors with LS carriers' histories of various cancers. Methods Two cohorts of LS carriers were analyzed: a laboratory-based cohort of consecutively ascertained individuals undergoing germline LS testing and a clinic-based cohort of LS carriers undergoing clinical care at an academic medical center. Multivariable logistic regression was performed to assess clinical factors associated with LS carriers' histories of various cancers/neoplasms. Familial burden was defined as LS carriers' aggregate number of first-/second-degree relatives with a history of a given malignancy. Results Multivariable analysis of the laboratory-based cohort (3828 LS carriers) identified familial burden as being incrementally associated with LS carriers' personal history of endometrial (odds ratio [OR], 1.37 per affected first-/second-degree relative; 95% confidence interval [CI], 1.21–1.56), urinary tract (OR, 2.72; 95% CI, 2.02–3.67), small bowel (OR, 3.17; 95% CI, 1.65–6.12), gastric (OR, 1.93; 95% CI, 1.24–3.02), and pancreaticobiliary cancers (OR, 2.10; 95% CI, 1.21–3.65) and sebaceous neoplasms (OR, 7.39; 95% CI, 2.71–20.15). Multivariable analysis of the clinic-based cohort (607 LS carriers) confirmed a significant association of familial burden of endometrial and urinary tract cancers. Conclusions Familial burden – in addition to age, sex, and specific LS gene – should be used to assess LS carriers' risks of specific cancers and guide decision-making about organ-specific surveillance.

Pancreatic ductal adenocarcinoma is an aggressive cancer with limited treatment options(1). Approximately 10% of cases exhibit familial predisposition, but causative genes are not known in most families(2). We perform whole-genome sequence analysis in a family with multiple cases of pancreatic ductal adenocarcinoma and identify a germline truncating mutation in the member of the RAS oncogene family-like (3) (RABL3) gene. Heterozygous rabl3 mutant zebrafish show increased susceptibility to cancer formation. Transcriptomic and mass spectrometry approaches implicate RABL3 in RAS pathway regulation and identify an interaction with RAP1GDS1 (SmgGDS), a chaperone regulating prenylation of RAS GTPases(3). Indeed, the truncated mutant RABL3 protein accelerates KRAS prenylation and requires RAS proteins to promote cell proliferation. Finally, evidence in patient cohorts with developmental disorders implicates germline RABL3 mutations in RASopathy syndromes. Our studies identify RABL3 mutations as a target for genetic testing in cancer families and uncover a mechanism for dysregulated RAS activity in development and cancer.

Background: Lynch syndrome confers markedly increased risks of various malignancies, including urinary tract cancers (UTC; renal pelvis, ureter, bladder, and possibly kidney cancers). It is unknown how to determine which Lynch syndrome carriers are at highest UTC risk. Our aim was to identify clinical factors associated with UTC among Lynch syndrome carriers. Methods: The study population was a cohort of 52,758 consecutively ascertained individuals undergoing Lynch syndrome testing at a commercial laboratory. Clinical data were obtained from test request forms completed by the ordering provider. Univariate analysis and multivariate logistic regression were performed to identify factors associated with UTC among Lynch syndrome carriers. Results: Compared with noncarriers, Lynch syndrome carriers were significantly more likely to have had UTC (4.1% vs. 1.2%; P < 0.0001). Lynch syndrome–associated UTC was independently associated with male sex [OR 1.95; 95% confidence interval (CI), 1.38–2.76], increased age (OR 2.44 per 10 years; 95% CI, 2.11–2.82), familial burden of UTC (OR 2.69 per first-/second-degree relative with UTC; 95% CI, 1.99–3.63), and pathogenic EPCAM/MSH2 variants (OR 4.01; 95% CI, 2.39–6.72) but not MLH1 variants (OR 1.17; 95% CI, 0.63–2.17), race, or history of other Lynch syndrome–associated malignancy. A total of 143 of 158 (90.5%) Lynch syndrome carriers with UTC had ≥1 of the following characteristics: male sex, EPCAM/MSH2 variants, or family history of UTC; 1,236 of 1,251 (98.8%) Lynch syndrome carriers lacking all of these characteristics had no history of UTC. Conclusions: Specific clinical factors can reliably identify Lynch syndrome carriers most likely to be at risk for UTC. Impact: A predictable subset of Lynch syndrome carriers may be most likely to benefit from UTC surveillance/prevention.

Background & Aims Lynch syndrome is the most common inherited cause of gastrointestinal cancer and increases risk for a variety of malignancies, including gastric cancer. We aimed to identify clinical factors associated with gastric cancer in carriers of germline variants causing Lynch syndrome. Methods We collected data from 52,758 consecutive individuals tested for genetic variants associated with Lynch syndrome from June 2006 through July 2013 at a commercial laboratory. We obtained clinical and demographic data, as well as information on personal and family histories of cancer (first- and second-degree relatives) from forms completed by ordering providers. We performed multivariate logistic regression to identify clinical factors associated with gastric cancer in carriers of mutations that cause Lynch syndrome (pathogenic mutations). Results After we excluded individuals with missing clinical data (n=1664) or with multiple pathogenic mutations (n=8), we analyzed data from 51,086 individuals. Of these, 3828 persons carried pathogenic mutations (1346 with mutations in MLH1 , 1639 with mutations in MSH2 , 670 with mutations in MSH6 , 145 with mutations in PMS2 , and 28 with mutations in EPCAM ). Of the 3828 carriers of pathogenic mutations, 41 (1.1%) had a previous gastric cancer and 350 (9.1%) had 1 or more first- or second-degree relatives with gastric cancer. In multivariate analysis, male sex (odds ratio [OR], 2.82; 95% CI, 1.48–5.38), older age (OR, 2.07 per 10 years; 95% CI, 1.64–2.61), mutations in MLH1 (OR, 6.53; 95% CI, 1.50–28.42) or MSH2 (OR, 5.23 compared to mutations in MSH6 , PMS2 , or EPCAM ; 95% CI, 1.21–22.71), and first-degree relative with gastric cancer (OR, 2.52; 95% CI, 1.42–4.45), but not second-degree relatives (OR, 1.12; 95% CI, 0.40–3.18) were independently associated with gastric among carriers of pathogenic mutations. Conclusions In an analysis of data from almost 4000 carriers of Lynch syndrome-associated mutations, we found history of gastric cancer to be independently associated with male sex, older age, mutations in MLH1 or MSH2 , and with having a first-degree relative with gastric cancer. These findings suggest that personalized, risk-stratified approaches to gastric cancer surveillance may be appropriate for individuals with Lynch syndrome-associated mutations.

1579 Background: Current clinical prediction models provide syndrome-specific numeric estimates of an individual's likelihood of having a specific hereditary cancer syndrome (e.g., PREMM5 for Lynch syndrome; BRCAPRO for BRCA1/2). With the emergence of multigene panel testing (MGPT), there is a need to evaluate individuals' risk of carrying a pathogenic variant in a diverse array of cancer susceptibility genes in parallel. This study’s aim was to develop and validate the PREMMplus clinical prediction model for multigene cancer risk assessment. Methods: PREMMplus was developed in a cohort of 7296 individuals who had undergone germline MGPT at a single center. Logistic regression models were used to examine candidate predictive variables – including age, sex, ethnicity, and personal/family history of cancer – to provide a numeric estimate of an individual’s likelihood of carrying a pathogenic/likely pathogenic germline variant in one of 18 cancer susceptibility genes (11 high- [ APC, BRCA1/2, CDH1, EPCAM, MLH1, MSH2, MSH6, biallelic MUTYH, PMS2, and TP53] and 7 moderate-penetrance [ ATM, CDKN2A, CHEK2, PALB2, PTEN, RAD51C, and RAD51D]). Model performance was validated in an independent dataset of 14845 individuals who had undergone MGPT at a commercial laboratory. Results: Using clinical characteristics, including personal/family history of 18 cancers plus colorectal adenoma burden, PREMMplus demonstrated an excellent ability to predict pathogenic variants in high penetrance genes at 90% sensitivity. PREMMplus had acceptable performance with the addition of 7 moderate penetrance genes. PREMMplus was well-calibrated and demonstrated comparable performance in the external validation dataset. Conclusions: PREMMplus is the first validated risk assessment model to quantify an individual’s likelihood of carrying pathogenic variants in a wide diversity of cancer risk genes, and can be used to select individuals who should undergo MGPT. As expected, PREMMplus’s discriminatory capacity was reduced with the inclusion of moderate penetrance cancer risk genes. [Table: see text]

678 Background: MGT identifies cancer susceptibility gene variants in 4-10% of unselected PC pts. Such data have prompted national guidelines to recommend GC and MGT of all PC pts, but the benefits and barriers to implementing systematic testing are unknown. This study’s aim was to study the implementation of universal GC for all PC pts seen in an academic oncology practice. Methods: In 12/2016, all Dana-Farber Cancer Institute (DFCI) gastrointestinal oncologists were recommended to refer all PC pts for GC and MGT. In 10/2018, workflows were changed such that PC patients were automatically scheduled for GC consultation on the same day as their initial oncologic evaluation (unless patients opted out), rather than relying on provider referral. Clinical and germline data were collected on a consecutive cohort of PC pts undergoing GC and MGT from 3/1/2017-3/31/2019. Two additional months (4/1/2019-5/31/2019) were collected for clinical quality assessment purposes. Results: 1305 (48.3/month) PC pts were seen for oncologic new patient visits, 318 (25.1%; 12.1/month) of whom underwent GC. Rates of GC/MGT increased significantly after the 10/2018 workflow change (8.2 PC pts/month [17.2% of all new PC pts seen] versus 20.3 PC pts/month, [40.9% of all new PC pts seen]; p

TPS4162 Background: 4-10% of PDAC patients harbor pathogenic germline variants in cancer susceptibility genes, including APC, ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, and TP53. For families with such pathogenic variants, the greatest potential impact of germline testing is to identify relatives with the same pathogenic variant (cascade testing), thereby providing the opportunity for early detection and cancer interception of PDAC and other associated malignancies. Numerous factors limit cascade testing in real-world practice, including family dynamics, widespread geographic distribution of relatives, access to genetic services, and misconceptions about the importance of germline testing, such that the preventive benefits of cascade testing are often not fully realized. The primary aim of this study is to analyze two alternative strategies for cascade testing in families with inherited PDAC susceptibility. Methods: 1000 individuals (from approximately 200 families) with a confirmed pathogenic germline variant in any of the above genes in a 1st/2nd degree relative and a 1st/2nd degree relative with PDAC will be remotely enrolled through the study website (www.generatestudy.org) and randomized between two different methods of cascade testing (individuals with prior genetic testing will be ineligible): Arm 1 will undergo pre-test genetic education with a pre-recorded video and live interactive session with a genetic counselor via a web-based telemedicine platform (Doxy.me), followed by germline testing through Color Genomics; Arm 2 will undergo germline testing through Color Genomics without dedicated pre-test genetic education. Color Genomics will disclose results to study personnel and directly to participants in both arms. Participants in both arms will have the option of pursuing additional telephone-based genetic counseling through Color Genomics. The primary outcome will be uptake of cascade testing. Secondary outcomes will include participant self-reported genetic knowledge, cancer worry, distress, decisional preparedness, familial communication, and screening uptake, which will be measured via longitudinal surveys. Enrollment will begin February, 2019. Clinical trial information: NCT03762590.

Objective To evaluate limitations of common statistical modeling approaches in deriving clinical prediction models and explore alternative strategies. Study Design and Setting A previously published model predicted the likelihood of having a mutation in germline DNA mismatch repair genes at the time of diagnosis of colorectal cancer. This model was based on a cohort where 38 mutations were found among 870 participants, with validation in an independent cohort with 35 mutations. The modeling strategy included stepwise selection of predictors from a pool of over 37 candidate predictors and dichotomization of continuous predictors. We simulated this strategy in small subsets of a large contemporary cohort (2,051 mutations among 19,866 participants) and made comparisons to other modeling approaches. All models were evaluated according to bias and discriminative ability (concordance index, c) in independent data. Results We found over 50% bias for five of six originally selected predictors, unstable model specification, and poor performance at validation (median c = 0.74). A small validation sample hampered stable assessment of performance. Model prespecification based on external knowledge and using continuous predictors led to better performance (c = 0.836 and c = 0.852 with 38 and 2,051 events respectively). Conclusion Prediction models perform poorly if based on small numbers of events and developed with common but suboptimal statistical approaches. Alternative modeling strategies to best exploit available predictive information need wider implementation, with collaborative research to increase sample sizes.

Survivors of childhood cancers are at increased risk of developing secondary gastrointestinal cancers, including colorectal cancer, later in life, possibly from exposure to abdominopelvic radiotherapy and/or alkylating chemotherapy. Profuse gastrointestinal polyposis is associated with rare, inherited colorectal cancer predisposition syndromes, most commonly caused by mutations in the adenomatous polyposis coli (APC) or mutY homolog (MUTYH) genes. We describe 5 patients who developed gastrointestinal polyposis many years after radiotherapy and chemotherapy for a childhood cancer. Genetic analysis of all 5 subjects did not identify pathogenic germline mutations in APC or MUTYH. Chemotherapy and/or radiotherapy therefore might cause gastrointestinal polyposis in some patients by undiscovered mechanisms.

1512Background: MGT will identify cancer susceptibility gene variants in 4-10% of unselected PC pts. Such data have prompted calls for universal GC and MGT of all PC pts, but the real-world benefit...

1517Background: LS is the one of the most common inherited causes of cancer and predisposes to a wide variety of cancers. UTCs (kidney, renal pelvis, ureter, and bladder cancer) are collectively th...

Background & Aims African Americans (AAs) have the highest incidence of and mortality resulting from colorectal cancer (CRC) in the United States. Few data are available on genetic and nongenetic risk factors for CRC among AAs. Little is known about cancer risks and mutations in mismatch repair (MMR) genes in AAs with the most common inherited CRC condition, Lynch syndrome. We aimed to characterize phenotype, mutation spectrum, and risk of CRC in AAs with Lynch syndrome. Methods We performed a retrospective study of AAs with mutations in MMR genes ( MLH1 , MSH2 , MSH6 , and PMS2 ) using databases from 13 US referral centers. We analyzed data on personal and family histories of cancer. Modified segregation analysis conditioned on ascertainment criteria was used to estimate age- and sex-specific CRC cumulative risk, studying members of the mutation-carrying families. Results We identified 51 AA families with deleterious mutations that disrupt function of the MMR gene product: 31 in MLH1 (61%), 11 in MSH2 (21%), 3 in MSH6 (6%), and 6 in PMS2 (12%); 8 mutations were detected in more than 1 individual, and 11 have not been previously reported. In the 920 members of the 51 families with deleterious mutations, the cumulative risks of CRC at 80 years of age were estimated to be 36.2% (95% confidence interval [CI], 10.5%–83.9%) for men and 29.7% (95% CI, 8.31%–76.1%) for women. CRC risk was significantly higher among individuals with mutations in MLH1 or MSH2 (hazard ratio, 13.9; 95% CI, 3.44–56.5). Conclusions We estimate the cumulative risk for CRC in AAs with MMR gene mutations to be similar to that of individuals of European descent with Lynch syndrome. Two-thirds of mutations were found in MLH1, some of which were found in multiple individuals and some that have not been previously reported. Differences in mutation spectrum are likely to reflect the genetic diversity of this population.