Germline Cancer Susceptibility Gene Testing in Unselected Patients With Colorectal Adenocarcinoma: A Multicenter Prospective Study.

BACKGROUND & AIMS: Hereditary factors play a role in the development of colorectal cancer (CRC). Identification of germline predisposition can have implications on treatment and cancer prevention. This study aimed to determine the prevalence of pathogenic germline variants (PGVs) in CRC patients using a universal testing approach, association with clinical outcomes, and the uptake of family variant testing. METHODS: We performed a prospective multisite study of germline sequencing using a more than 80-gene next-generation sequencing platform among CRC patients (not selected for age or family history) receiving care at Mayo Clinic Cancer Centers between April 1, 2018, and March 31, 2020. RESULTS: Of 361 patients, the median age was 57 years (SD, 12.4 y), 43.5% were female, 82% were white, and 38.2% had stage IV disease. PGVs were found in 15.5% (n = 56) of patients, including 44 in moderate- and high-penetrance cancer susceptibility genes. Thirty-four (9.4%) patients had incremental clinically actionable findings that would not have been detected by practice guideline criteria or a CRC-specific gene panel. Only younger age at diagnosis was associated with the presence of PGVs (odds ratio, 1.99; 95% CI, 1.12-3.56). After a median follow-up period of 20.7 months, no differences in overall survival were seen between those with or without a PGV (P = .2). Eleven percent of patients had modifications in their treatment based on genetic findings. Family cascade testing was low (16%). CONCLUSIONS: Universal multigene panel testing in CRC was associated with a modest, but significant, detection of heritable mutations over guideline-based testing. One in 10 patients had changes in their management based on test results. Uptake of cascade family testing was low, which is a concerning observation that warrants further study.

Clinical Impact of Pathogenic Germline Variants in Pancreatic Cancer: Results From a Multicenter, Prospective, Universal Genetic Testing Study.

INTRODUCTION: To report the prevalence and outcomes of unselected pancreatic cancer (PC) patients with pathogenic/likely pathogenic germline variants (PGVs) detected using a universal testing approach. METHODS: We undertook a prospective, multisite study of germline sequencing using a >80 gene next-generation sequencing platform among 250 patients with PC (not selected for age or family history of cancer) between April 1, 2018, and March 31, 2020. Demographic, tumor characteristics, and clinical outcomes were compared between PGV carriers and noncarriers. RESULTS: Of 250 patients, the mean age was 65 years (SD 8.7), 56% was male, 83.6% was White, and 65.6% had advanced disease (stages III and IV). PGVs were found in 15.2% (N = 38) of patients, and 2 patients had more than 1 PGV. Variants of uncertain significance were found in 44.4% (N = 111). Family history of cancer (odds ratio: 2.36, 95% confidence interval: 1.14-5.19, P = 0.025) was associated with a higher risk of PGV. In a median follow-up of 16.5 months, the median overall survival was 16.8 months in PGV carriers compared with 16.5 months in noncarriers (hazard ratio: 0.51, 95% confidence interval: 0.25-1.01, P = 0.05). Higher levels of carbohydrate antigen 19-9 and advanced disease stages (III and IV) were associated with worse outcomes in both groups. Overall, 68% of PGV carriers had mutations in homologous recombination repair genes, including BRCA1, BRCA2, PALB2, ATM, CHEK2, NBN, and RAD51C. DISCUSSION: Universal multigene panel testing in PC reveals that 1 in 6 patients are carriers of PGV. Multigene germline testing should be used to aid in treatment selection, prognostication, and familial cancer counseling.

Comparison of Universal Genetic Testing vs Guideline-Directed Targeted Testing for Patients With Hereditary Cancer Syndrome.

IMPORTANCE: Hereditary factors play a key role in the risk of developing several cancers. Identification of a germline predisposition can have important implications for treatment decisions, risk-reducing interventions, cancer screening, and germline testing. OBJECTIVE: To examine the prevalence of pathogenic germline variants (PGVs) in patients with cancer using a universal testing approach compared with targeted testing based on clinical guidelines and the uptake of cascade family variant testing (FVT). DESIGN, SETTING, AND PARTICIPANTS: This prospective, multicenter cohort study assessed germline genetic alterations among patients with solid tumor cancer receiving care at Mayo Clinic cancer centers and a community practice between April 1, 2018, and March 31, 2020. Patients were not selected based on cancer type, disease stage, family history of cancer, ethnicity, or age. EXPOSURES: Germline sequencing using a greater than 80-gene next-generation sequencing platform. MAIN OUTCOMES AND MEASURES: Proportion of PGVs detected with a universal strategy compared with a guideline-directed approach and uptake of cascade FVT in families. RESULTS: A total of 2984 patients (mean [SD] age, 61.4 [12.2] years; 1582 [53.0%] male) were studied. Pathogenic germline variants were found in 397 patients (13.3%), including 282 moderate- and high-penetrance cancer susceptibility genes. Variants of uncertain significance were found in 1415 patients (47.4%). A total of 192 patients (6.4%) had incremental clinically actionable findings that would not have been detected by phenotype or family history-based testing criteria. Of those with a high-penetrance PGV, 42 patients (28.2%) had modifications in their treatment based on the finding. Only younger age of diagnosis was associated with presence of PGV. Only 70 patients (17.6%) with PGVs had family members undergoing no-cost cascade FVT. CONCLUSIONS AND RELEVANCE: This prospective, multicenter cohort study found that universal multigene panel testing among patients with solid tumor cancer was associated with an increased detection of heritable variants over the predicted yield of targeted testing based on guidelines. Nearly 30% of patients with high-penetrance variants had modifications in their treatment. Uptake of cascade FVT was low despite being offered at no cost.

Worst outcomes according to RAS mutation variants: an analysis in patients with metastatic colorectal adenocarcinoma.

PURPOSE: Over 50% of metastatic colorectal cancers harbor RAS mutations. It is unclear if different mutation variants have an impact on survival. The purpose of this study was to evaluate the impact of these mutations on colorectal cancer survival. METHODS: The charts of all cases of metastatic colorectal cancer diagnosed between January 2005 and January 2016 in a tertiary hospital in Brazil were reviewed. Inclusion criteria were complete data on clinical staging, treatments received and all-RAS testing. Multivariate Cox proportional survival models were used to evaluate the impact of specific RAS variants on survival. RESULTS: There were 151 eligible patients and 61.6% had RAS alterations, the most common G12D (11.9%) and G12A (8.6%). Most patients received chemotherapy, including oxaliplatin (79%), irinotecan (53%) and bevacizumab (59%). Among RAS-wild type patients, 46% received anti-EGFR therapy. Median survival was 39.2 months for RAS-wildtype, 18.8 months for RAS G12A and 34.6 for other RASmutant patients (multivariate analysis for G12A vs RASwild type HR 1.94; 95% CI 0.83-5.51; p=0.12). CONCLUSION: Patients with metastatic colorectal cancer who have RAS mutations have shorter overall survival. Regarding the impact of specific KRAS alterations, G12A mutations have a worse prognosis.