Detection of germline variants using expanded multigene panels in patients with localized pancreatic cancer.

Background: Current guidelines recommend genetic testing for all patients with pancreatic cancer (PC).

Methods: Patients with localized PC who received neoadjuvant therapy between 2009 and 2018 were identified. Genetic consultation (including personal and family history of cancer), genetic testing, and variant data were abstracted.

Results: Of 510 patients identified, 163 (32%) underwent genetic counseling and genetic testing was performed in 127 (25%). Patients who underwent genetic testing were younger (median age: 63 vs. 67, p = 0.01). Multi-gene testing was performed in 114 (90%) of 127 patients, targeted gene testing was performed in 8 (6%), and not specified in 5 (4%). Of 127 patients who underwent genetic testing, 20 (16%) had pathogenic (P)/likely pathogenic (LP) variants, observed in ATM (n = 7/105,7%), CHEK2 (n = 3/98, 3%), BRCA1 (n = 2/117, 2%), BRCA2 (n = 2/122, 2%), PALB2 (n = 1/115, 1%), MUTYH (n = 1/98, 1%), CDKN2A (n = 1/94, 1%), STK11 (n = 1/97, 1%), NBN (n = 1/98, 1%), and MSH6 (n = 1/97, 1%). Of 20 patients with either a P/LP variant, nine (45%) had a prior cancer, three (15%) had a first-degree relative with PC, and six (30%) had an any-degree relative with PC.

Conclusion: Pathogenic/likely pathogenic variants were identified in 16% of patients who underwent genetic testing, 60% of which occurred in the homologous recombination pathway.