Germline testing in patients with early-onset pancreatic cancer (EOPC).

Abstract

639 Background: EOPC, defined as pancreatic cancer (PC) diagnosed at 60 years of age or younger, is associated with significant life years lost. Approximately 5-10% of average-onset PC have an underlying germline etiology. Currently NCCN & ASCO guidelines recommend germline testing in all pts w PC. However, there is limited data regarding to what extent pts with EOPC pursue recommended germline testing. We examined the findings from genetic evaluation in EOPC. Methods: A retrospective review of EOPC pts at the Levine Cancer Institute who underwent clinical genetic assessment between January 2019 and December 2021 was performed. Data on clinicodemographic, family history, and genetic testing results were obtained and analyzed descriptively. Results: We identified 69 EOPC pts who were evaluated by genetics. Baseline characteristics include median age of 55 years (range 25-60) with 52% male, 48% white, 23% black, and 52% with current or prior tobacco use. At presentation, 41% and 59% had metastatic and non-metastatic disease, respectively. Eight (12%) pts declined germline testing. Among the 61 who underwent germline testing, 30 (49%) pts had negative testing, 21 (34%) had only variants of uncertain significance, and 10 (16%) had pathogenic/likely pathogenic germline variants (PVs). The most frequently seen PVs were ATM (20%), BRCA1 (20%), BRCA2 (10%), MLH1 (10%), NTHL1 (10%), PTCH1 (10%), CFTR (10%) and one (10%) with multiple pathogenic germline findings including RAD51 and BRCA1. Among the 10 pts with PVs, only two reported any first or second-degree family members with cancer. Conclusions: In this cohort of EOPC at a large community multi-site cancer center, 16% of patients had germline PVs, higher than reported in older patients with PC. Only 20% of pts w PVs reported first or second-degree family members with cancer and highlights the importance to recommend germline testing independent of family history even among EOPC cohorts. Further investigation to clarify reasons for refusal of germline testing in EOPC should be evaluated.