title: A case-control study comparing the incidence of early symptoms in pancreatic and biliary tract cancer.
abstract: OBJECTIVE
  Pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancers (BTC) are often diagnosed late and at an advanced stage. Population-based screening programmes do not exist and diagnosis is primarily dependent on symptom recognition. Recently symptom-based cancer decision support tools (CDSTs) have been introduced into primary care practices throughout the UK to support general practitioners (GPs) in identifying patients with suspected PDAC. However, future refinement of these tools to improve their diagnostic accuracy is likely to be necessary.
  
  
  METHODS
  The Health Improvement Network (THIN) is a primary care database, which includes more than 11 million electronic patient records, from 562 GP practices in the UK.
  
  
  METHODS
  All patients with a diagnosis of PDAC or BTC between 2000 and 2010 were included in the study along with six matched controls; 2773 patients with PDAC, 848 patients with BTC and 15,395 controls.
  
  
  METHODS
  The primary aim of this study was to determine the early symptom profiles of PDAC and BTC. Secondary aims included comparing early symptom trends between BTC and PDAC, defining symptom onset in PDAC and evaluating trends in routine blood tests nearest to the time of diagnosis.
  
  
  RESULTS
  In the year prior to diagnosis, patients with PDAC visited their GP on a median of 18 (IQR 11-27) occasions. PDAC was associated with 11 alarm symptoms and BTC with 8. Back pain (OR 1.33 (95% CI 1.18 to 1.49) p<0.001), lethargy (1.42 (95% CI 1.25 to 1.62) p<0.001) and new onset diabetes (OR 2.46 (95% CI 2.16 to 2.80)) were identified as unique features of PDAC.
  
  
  CONCLUSIONS
  PDAC and BTC are associated with numerous early alarm symptoms. CDSTs are therefore likely to be useful in identifying these tumours at an early stage. Inclusion of unique symptoms, symptoms with an early onset and routinely performed blood tests is likely to further improve the sensitivity of these tools.
authors.affiliation: Institute for Liver and Digestive Health, University College London, London, UK.
authors.forename: M G
authors.initials: MG
authors.lastname: Keane
authors.affiliation: Research Department of Primary Care and Population Health, University College London, London, UK.
authors.forename: L
authors.initials: L
authors.lastname: Horsfall
authors.affiliation: Research Department of Primary Care and Population Health, University College London, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Rait
authors.affiliation: Institute for Liver and Digestive Health, University College London, London, UK.
authors.forename: S P
authors.initials: SP
authors.lastname: Pereira
mesh_terms: D015746:Abdominal Pain / Q000453:epidemiology / Q000503:physiopathology; D000368:Aged; D001416:Back Pain / Q000453:epidemiology / Q000503:physiopathology; D001661:Biliary Tract Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology*; D021441:Carcinoma, Pancreatic Ductal / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology*; D016022:Case-Control Studies; D015897:Comorbidity; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D010190:Pancreatic Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology*; D006113:United Kingdom / Q000453:epidemiology
keywords: PRIMARY CARE