Clinical Significance of Germline Cancer Predisposing Variants in Unselected Patients with Pancreatic Adenocarcinoma

Simple Summary Data on the prognostic and predictive value of germline cancer predisposing pathogenic/likely pathogenic variants (P/LPVs) in patients with pancreatic ductal adenocarcinoma is limited. This research was a study of germline testing of 62 cancer susceptibility genes in 549 unselected patients with pancreatic cancer. We reported a significant proportion of European patients with pancreatic cancer carrying P/LPVs in clinically significant genes, irrespectively of age, family history or disease stage. Importantly, P/LPVs were identified in pancreatic cancer-associated genes and in homologous recombination repair genes in 4.0% and 7.7% of patients, respectively. The presence of any P/LPVs was associated with improved overall survival univariately; however, it did not retain its independent prognostic significance in multivariate analysis. The presence of P/LPVs in homologous recombination repair genes did not predict benefit from platinum-based treatment. These results should be prospectively validated through universal genetic testing of patients with pancreatic cancer, taking into consideration the administration of newer treatments. Abstract Our aim was to determine the prevalence, prognostic and predictive role of germline pathogenic/likely pathogenic variants (P/LPVs) in cancer predisposing genes in patients with pancreatic ductal adenocarcinoma (PDAC). Germline testing of 62 cancer susceptibility genes was performed on unselected patients diagnosed from 02/2003 to 01/2020 with PDAC, treated at Hellenic Cooperative Oncology Group (HeCOG)-affiliated Centers. The main endpoints were prevalence of P/LPVs and overall survival (OS). P/LPVs in PDAC-associated and homologous recombination repair (HRR) genes were identified in 22 (4.0%) and 42 (7.7%) of 549 patients, respectively. P/LPVs were identified in 16 genes, including ATM (11, 2.0%) and BRCA2 (6, 1.1%), while 19 patients (3.5%) were heterozygotes for MUTYH P/LPVs and 9 (1.6%) carried the low-risk allele, CHEK2 p.(Ile157Thr). Patients carrying P/LPVs had improved OS compared to non-carriers (22.6 vs. 13.9 months, p = 0.006). In multivariate analysis, there was a trend for improved OS in P/LPV carriers (p = 0.063). The interaction term between platinum exposure and mutational status of HRR genes was not significant (p-value = 0.35). A significant proportion of patients with PDAC carries clinically relevant germline P/LPVs, irrespectively of age, family history or disease stage. The predictive role of these P/LPVs has yet to be defined. ClinicalTrials.gov Identifier: NCT03982446.