Germline Pathogenic Variants in Patients With Pancreatic and Periampullary Cancers.

Abstract

Inherited cancer susceptibility is often not suspected in the absence of a significant cancer family history. Pathogenic germline variants in pancreatic cancer are well-studied, and routine genetic testing is recommended in the guidelines. However, data on rare periampullary cancers other than pancreatic cancer are insufficient. We compared the prevalence of germline susceptibility variants in patients with pancreatic cancer and nonpancreatic periampullary cancers. Six hundred and eight patients who had undergone pancreaticoduodenal resection at a tertiary referral hospital were studied, including 213 with pancreatic ductal adenocarcinoma, 172 with ampullary cancer, 154 with distal common bile duct cancer, and 69 with duodenal adenocarcinoma. Twenty cancer susceptibility and candidate susceptibility genes were sequenced, and variant interpretation was assessed by interrogating ClinVar and PubMed. Pathogenic or likely pathogenic, moderate- to high-penetrant germline variants were identified in 46 patients (7.7%), including a similar percentage of patients with pancreatic (8.5%) and nonpancreatic periampullary cancer (7.1%). Low-penetrant variants were identified in an additional 11 patients (1.8%). Eighty-nine percent of the moderate- to high-penetrant variants involved the major cancer susceptibility genes <i>BRCA2</i>, <i>ATM</i>, <i>BRCA1</i>, <i>CDKN2A</i>, <i>MSH2</i>/<i>MLH1</i>, and <i>PALB2</i>; the remaining 11% involved other cancer susceptibility genes such as <i>BRIP1</i>, <i>BAP1</i>, and <i>MSH6</i>. Almost all pathogenic variant carriers had a family history of cancer. Patients with pancreatic and nonpancreatic periampullary cancer have a similar prevalence of pathogenic cancer susceptibility variants. Germline susceptibility testing should be considered for patients with any periampullary cancer.