Hereditary Cancer Clinics Improve Adherence to NCCN Germline Testing Guidelines for Pancreatic Cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, with a 5-year overall survival rate of 10%. In November 2018, NCCN recommended that all patients with PDAC receive genetic counseling (GC) and germline testing regardless of family history. We hypothesized that patients with PDAC were more likely to be referred for testing after this change to the guidelines, regardless of presumed predictive factors, and that compliance would be further improved following the implementation of a hereditary cancer clinic (HCC). METHODS: We conducted a single-institution retrospective analysis of patients diagnosed with PDAC from June 2017 through December 2021 at University of California, Irvine. We compared rates of genetics referral among patients in different diagnostic eras: the 18-month period before the NCCN Guideline change (pre-NCCN era: June 2017 through November 2018), 14 months following the change (post-NCCN era: December 2018 through January 2020), and 18 months after the creation of an HCC (HCC era: June 2020 through December 2021). Family and personal cancer history, genetics referral patterns, and results of GC were recorded. Data were compared using chi-square, Fisher exact, and multivariate analyses. RESULTS: A total of 335 patients were treated for PDAC (123 pre-NCCN, 109 post-NCCN, and 103 HCC) at University of California, Irvine. Demographics across groups were comparable. Prior to the guideline changes, 30% were referred to GC compared with 54.7% in the post-NCCN era. After the implementation of the HCC, 77.4% were referred to GC (P<.0001). The odds ratio (OR) for referral to GC among patients with a positive family history of cancer progressively decreased following the change (pre-NCCN era: OR, 11.90 [95% CI, 3.00-80.14]; post-NCCN era: OR, 3.39 [95% CI, 1.13-10.76]; HCC era: OR, 3.11 [95% CI, 0.95-10.16]). CONCLUSIONS: The 2018 updates to the NCCN Guidelines for PDAC recommending germline testing for all patients with PDAC significantly increased GC referral rates at our academic medical center. Implementation of an HCC further boosted compliance with guidelines.

Splicing profile by capture RNA-seq identifies pathogenic germline variants in tumor suppressor genes.

Germline variants in tumor suppressor genes (TSGs) can result in RNA mis-splicing and predisposition to cancer. However, identification of variants that impact splicing remains a challenge, contributing to a substantial proportion of patients with suspected hereditary cancer syndromes remaining without a molecular diagnosis. To address this, we used capture RNA-sequencing (RNA-seq) to generate a splicing profile of 18 TSGs (APC, ATM, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MLH1, MSH2, MSH6, MUTYH, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, and TP53) in 345 whole-blood samples from healthy donors. We subsequently demonstrated that this approach can detect mis-splicing by comparing splicing profiles from the control dataset to profiles generated from whole blood of individuals previously identified with pathogenic germline splicing variants in these genes. To assess the utility of our TSG splicing profile to prospectively identify pathogenic splicing variants, we performed concurrent capture DNA and RNA-seq in a cohort of 1000 patients with suspected hereditary cancer syndromes. This approach improved the diagnostic yield in this cohort, resulting in a 9.1% relative increase in the detection of pathogenic variants, demonstrating the utility of performing simultaneous DNA and RNA genetic testing in a clinical context.

Ethnic disparities in the frequency of cancer reported in family histories.

This study was designed to observe whether disparities exist between ethnicities in reporting a family history of cancer in a cancer genetic counseling clinic. Four hundred sixty-nine pedigrees collected between 2015 to 2017 from a cancer clinic at the University of California, Irvine, were analyzed. Pedigrees were separated by ethnicity into the following categories: non-Hispanic White, Hispanic, Asian, or Ashkenazi Jewish. The number of first- and second-degree relatives was calculated for each pedigree, and the total number of relatives reported with cancer. The total reported with cancer was divided by total number of relatives to derive a percentage of cancer reporting for each pedigree. The percentages of cancer reporting were analyzed using column proportions, nonparametric tests, and a Poisson regression. Cancer reporting in first- and second-degree relatives was highest among non-Hispanic Whites and Ashkenazi Jewish individuals, with median percentages of 22% and 27%, respectively. The median percentage of cancer reporting in first- and second-degree relatives in both Hispanics and Asians was 10%. Cancer reporting medians were significantly lower in Hispanics and Asians when compared to non-Hispanic Whites and Ashkenazi Jewish individuals (p < .001). Ethnicity was a significant factor for predicting the number of relatives reported to have cancer when analyzed with a Poisson regression. This study concluded that cancer is reported less frequently in families when the proband and their families are Hispanic or Asian. Hispanics and Asians have lower cancer incidence rates; however, incidence rates alone may not explain the reporting disparity observed. Hence, family cancer histories in minority populations may be truncated. Healthcare professionals should be aware of this disparity when assessing cancer risks so appropriate modifications can be made accordingly for recommended cancer screening and/or cancer genetic testing. Further efforts are warranted to disseminate information to minority populations about the value of family health history regarding cancer risk assessment.

Variables affecting penetrance of gastric and duodenal phenotype in familial adenomatous polyposis patients.

BACKGROUND: Patients with familial adenomatous polyposis (FAP) frequently undergo colectomy to reduce the 70 to 90% lifetime risk of colorectal cancer. After risk-reducing colectomy, duodenal cancer and complications from duodenal surgeries are the main cause of morbidity. Our objective was to prospectively describe the duodenal and gastric polyp phenotype in a cohort of 150 FAP patients undergoing pre-screening for a chemoprevention trial and analyze variables that may affect recommendations for surveillance. METHODS: Individuals with a diagnosis of FAP underwent prospective esophagogastroduodenoscopy using a uniform system of mapping of size and number of duodenal polyps for a 10 cm segment. Gastric polyps were recorded as the total number. RESULTS: The distribution of the count and sum diameter of duodenal polyps were statistically different in two genotype groups, those with APC mutations associated with classic FAP had a greater count (median 17) and sum diameter of polyps (median 32 mm) than those with APC mutations associated with attenuated FAP (median count 4 and median sum diameter of 7 mm) (p < 0.0001). The number of gastric polyps did not differ based on genotype (p = 0.67) but advancing age correlated with severity of gastric polyposis (p = 0.019). Spigelman (modified) staging of II or greater was found in 88% of classic FAP patients and 48% attenuated FAP patients. Examples of severe and mild upper GI phenotype are observed in patients with identical APC mutations, showing that the APC mutation location is not absolutely predictive of an upper GI phenotype. CONCLUSIONS: Most FAP patients have duodenal and gastric polyps which become more prevalent and advanced with age. Standard upper endoscopic surveillance is recommended based on personal history independent of APC mutation location. TRIAL REGISTRATION: NCT 01187901 registered August 24, 2010, prospective to enrollment.

Parent decision-making around the genetic testing of children for germline TP53 mutations.

BACKGROUND: Li-Fraumeni syndrome is a rare genetic cancer predisposition syndrome caused by germline TP53 mutations. Up to 20% of mutation carriers develop cancer during childhood. The benefits of TP53 mutation testing of children are a matter of debate and knowledge of parent decision-making around such testing is limited. The current study examined how parents make decisions regarding TP53 testing for their children. METHODS: Families offered and those pursuing TP53 testing for their children were identified across the study sites. Qualitative interviews with 46 parents (39 families) were analyzed to describe decision-making styles and perceived advantages and disadvantages of testing. RESULTS: TP53 mutation testing uptake was high (92%). Three decision-making styles emerged. Automatic decisions (44% of decisions) involved little thought and identified immediate benefit(s) in testing (100% pursued testing). Considered decisions (49%) weighed the risks and benefits but were made easily (77% pursued testing). Deliberated decisions (6%) were difficult and focused on psychosocial concerns (25% pursued testing). Perceived advantages of testing included promoting child health, satisfying a "need to know," understanding why cancer(s) occurred, suggesting family member risk, and benefiting research. Disadvantages included psychosocial risks and privacy/discrimination/insurance issues. CONCLUSIONS: Although empirical evidence regarding the benefits and risks of TP53 testing during childhood are lacking, the majority of parents in the current study decided easily in favor of testing and perceived a range of advantages. The authors conclude that in the context of a clinical diagnosis of Li-Fraumeni syndrome, parents should continue to be offered TP53 testing for their children, counseled regarding potential risks and benefits, and supported in their decision-making process.