title: Familial Risk of Biliary Tract Cancers: A Population-Based Study in Utah.
abstract: Biliary tract cancers (BTC) including, cholangiocarcinoma (CC) and gallbladder cancer (GBC), are rare and highly fatal malignancies. The etiology and inherited susceptibility of both malignancies are poorly understood. We quantified the risk of BTC in first-degree (FDR), second-degree (SDR), and first cousin (FC) relatives of individuals with BTC, stratified by tumor subsite.
  
  
  
  BTC diagnosed between 1980 and 2011 were identified from the Utah Cancer Registry and linked to pedigrees from the Utah Population Database. Age- and gender-matched BTC-free controls were selected to form the comparison group for determining BTC risk in relatives using Cox regression analysis.
  
  
  
  Of the 1302 index patients diagnosed with BTC, 550 (42.2 %) were located in the gallbladder and 752 (57.8 %) were cholangiocarcinomas. There was no elevated risk of BTC (all subsites combined) in FDRs (HR 0.94, 95 % CI 0.29-3.0), SDRs (HR 0.25, 95 % CI 0.06-1.03), and FCs (HR 0.96, 95 % CI 0.61-1.51) of BTC cases compared to cancer-free controls. Similarly, no increased familial risk of GBC or CC was found in relatives of BTC patients stratified by tumor subsite compared to relatives of controls.
  
  
  
  Relatives of BTC patients are not at an increased risk of GBC or CC in a statewide population. This suggests that biliary tract cancer risk is not associated with a familial predisposition and may be mitigated more strongly by environmental modifiers.
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA. Jewel.samadder@hsc.utah.edu.|Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, UT, USA. Jewel.samadder@hsc.utah.edu.
authors.forename: N Jewel
authors.initials: NJ
authors.lastname: Samadder
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA.|Department of Family and Consumer Studies, University of Utah, Salt Lake City, UT, USA.
authors.forename: Ken Robert
authors.initials: KR
authors.lastname: Smith
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA.
authors.forename: Jathine
authors.initials: J
authors.lastname: Wong
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA.|Department of Family and Preventive Medicine, University of Utah, Salt Lake City, UT, USA.
authors.forename: Heidi
authors.initials: H
authors.lastname: Hanson
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA.|Department of Medicine (Epidemiology), University of Utah, Salt Lake City, UT, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Boucher
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA.|Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, UT, USA.|Department of Oncological Sciences, University of Utah, Salt Lake City, UT, USA.
authors.forename: Randall W
authors.initials: RW
authors.lastname: Burt
authors.affiliation: Department of Medicine, Intermountain Healthcare, Salt Lake City, UT, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Charlton
authors.affiliation: Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, UT, USA.
authors.forename: Kathryn R
authors.initials: KR
authors.lastname: Byrne
authors.affiliation: Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, UT, USA.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Gallegos-Orozco
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA.
authors.forename: Cathryn
authors.initials: C
authors.lastname: Koptiuch
authors.affiliation: Cancer Control and Population Sciences, Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT, 84112, USA.|Department of Medicine (Genetic Epidemiology), University of Utah, Salt Lake City, UT, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Curtin
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000453:epidemiology / Q000235:genetics*; D017734:Bile Ducts, Extrahepatic; D001653:Bile Ducts, Intrahepatic; D001661:Biliary Tract Neoplasms / Q000453:epidemiology / Q000235:genetics; D018281:Cholangiocarcinoma / Q000453:epidemiology / Q000235:genetics*; D005190:Family; D005260:Female; D005706:Gallbladder Neoplasms / Q000453:epidemiology / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D016016:Proportional Hazards Models; D012042:Registries; D014589:Utah / Q000453:epidemiology; D055815:Young Adult
keywords: Biliary tract; Cholangiocarcinoma; Familial; Gallbladder cancer