DEVELOPMENT OF A NOVEL GENETIC TESTING PROTOCOL FOR PANCREATIC DUCTAL ADENOCARCINOMA PATIENTS IN KENTUCKY
Megan M. Harper*1,2, Andrew J. Kennedy1, Reema A. Patel1,2, Aileen Alqueza2, Jonathan Davis2, Tamara E. Carey2, Jessica Moss1,2, Prakash K. Pandalai1,2, Michael J. Cavnar1,2, Justine C. Pickarski2, Joseph Kim1,2
1University of Kentucky Medical Center, Lexington, KY; 2Markey Cancer Center, Lexington, KY
Introduction: With recently updated NCCN guidelines, all patients diagnosed with pancreatic adenocarcinoma (PDAC) are advised to undergo germline genetic testing. However, genetic counseling remains a limited resource, necessitating a new approach to optimal implementation. Here, we describe the development of a novel protocol where all patients diagnosed or referred to our team with PDAC undergo genetic testing and brief counseling.
Methods: At the initial appointment, all PDAC patients receive an overview of genetic testing by medical or surgical oncology, a brochure on insurance coverage, and data on how results can affect family members. Then patients are offered genetic testing, which focuses on identifying germline mutations that are known to increase risk for familial pancreatic cancer (FPC). If deleterious mutations are identified, patients then undergo formal genetic counseling and family members are subsequently offered genetic testing. If these family members harbor deleterious mutations, they are enrolled into a high-risk PDAC clinic with counseling, testing of CA19-9 levels, and screening with EUS or MRI.
Results: From 2017-2019, prior to implementation of our protocol, 33 of 34 patients meeting criteria for FPC were tested at our institution. Since the implementation of our protocol in 2020, we have tested 125 PDAC patients and offered testing to an additional 4 patients who declined including 1 who had testing performed prior to presentation, thereby capturing 97% of our PDAC cohort. Of the 120 available results, 16 (13.3%) patients demonstrated the following mutations associated with FPC: ATM (n=4, 3.3%), BRCA1/2/PALB2 (n=2, 1.7%), CDKN2A (n=2, 1.7%), CFTR carriers (n=3, 2.5%), EPCAM/MLH1/MSH2/MSH6/PMS2 (n=1, 0.8%), MUTYH (n=2, 1.7%). Additional mutations in Rad50 (n=1, 0.8%) and HOXB13 (n=2, 1.7%), known to increase overall cancer risk, have also been identified. Furthermore, 20 (16.7%) patients had mutations of unknown significance (MUS) in genes associated with increased overall cancer risk and/or PDAC development. An additional 19 patients have MUS without known cancer associations.
Discussion: NCCN recommendations to provide genetic testing to all PDAC patients can strain limited genetic counseling resources. Here we demonstrate successful protocol implementation enabling a high volume PDAC academic center to implement a genetic testing program without placing strain on genetic counseling resources. As we expand our program, we aim to identify affected family members at the greatest risk for PDAC in order to detect cancer in the earliest disease stages.
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