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PURPOSE: Up to 25% of pancreatic adenocarcinomas (PDACs) harbor mutations in the homologous recombination DNA damage response (HR-DDR) pathway. Although known to affect responsiveness to DNA-damaging chemotherapy, the prognostic relevance of these mutations is unclear and outcomes in patients with PDAC who harbor HR-DDR mutations beyond BRCA1/2 remain unexplored. METHODS: We evaluated 820 patients with PDAC enrolled in the Know Your Tumor program for whom we had collected comprehensive genomic testing results and longitudinal clinical outcomes. Patients were categorized as having resected versus advanced disease, and as having received platinum-based therapy versus being platinum naïve. Tumor genomic profiles were categorized as HR-DDR mutated (HR-DDRmut) or proficient (pHR-DDR) on the basis of the presence of pathogenic mutations of somatic or germline origin in BRCA1/2 or PALB2 (group 1); ATM/ATR/ATRX (group 2); or BAP1, BARD1, BRIP1, CHEK1/2, RAD50/51/51B, or FANCA/C/D2/E/F/G/L (group 3). Overall survival was measured from the date of diagnosis until death. RESULTS: Median overall survival (mOS) was similar in all resected patients irrespective of exposure to platinum-based therapy, whereas for platinum-treated patients with advanced disease, mOS was significantly longer for HR-DDRmut versus pHR-DDR (2.37 years v 1.45 years, respectively). Of importance, no difference was identified in platinum-naïve patients. mOS in patients with mutations in all three HR-DDRmut groups was greater than that for pHR-DDR patients, but this difference was lost in platinum-naïve patients. CONCLUSION: Patients with advanced HR-DDRmut have improved mOS when treated with platinum-based therapy compared with pHR-DDR patients. In platinum-naïve patients, there is no mOS difference, which suggests that HR-DDR status has no pure prognostic value. These findings support the need to test all patients with advanced PDAC to ensure that HR-DDRmut patients receive the benefit of treatment with platinum-based therapy. [ABSTRACT FROM AUTHOR]

PURPOSE: It has been estimated that 5% to 10% of cancers are due to hereditary causes. Recent data sets indicate that the incidence of hereditary cancer may be as high as 17.5% in patients with cancer, and a notable subset is missed if screening is solely by family history and current syndrome-based testing guidelines. Identification of germline variants has implications for both patients and their families. There is currently no comprehensive overview of cancer susceptibility genes or inclusion of these genes in commercially available somatic testing. We aimed to summarize genes linked to hereditary cancer and the somatic and germline panels that include such genes. METHODS: Germline predisposition genes were chosen if commercially available for testing. Penetrance was defined as low, moderate, or high according to whether the gene conferred a 0% to 20%, 20% to 50%, or 50% to 100% lifetime risk of developing the cancer or, when percentages were not available, was estimated on the basis of existing literature descriptions. RESULTS: We identified a total of 89 genes linked to hereditary cancer predisposition, and we summarized these genes alphabetically and by organ system. We considered four germline and six somatic commercially available panel tests and quantified the coverage of germline genes across them. Comparison between the number of genes that had germline importance and the number of genes included in somatic testing showed that many but not all germline genes are tested by frequently used somatic panels. CONCLUSION: The inclusion of cancer-predisposing genes in somatic variant testing panels makes incidental germline findings likely. Although somatic testing can be used to screen for germline variants, this strategy is inadequate for comprehensive screening. Access to genetic counseling is essential for interpretation of germline implications of somatic testing and implementation of appropriate screening and follow-up. [ABSTRACT FROM AUTHOR]