title: New diagnosis of chronic pancreatitis: risk of missing an underlying pancreatic cancer.
abstract: OBJECTIVE
  Patients with pancreatic cancer (PaCa) sometimes present with symptoms suggestive of chronic pancreatitis (CP). We evaluated the prevalence of undiagnosed PaCa in patients with new CP diagnosis.
  
  
  METHODS
  This is a retrospective study with data from Veterans Health Administration national medical care data sets from fiscal year 1998-2007. A 3-year washout period was used to identify patients with preexisting PaCa and preexisting CP diagnosis.
  
  
  RESULTS
  Among 471,992 veterans included, 917 (0.19%) had PaCa, 2,557 (0.54%) had a preexisting CP, and 2,175 (0.46%) had a new diagnosis of CP. PaCa was diagnosed ≤2 years following CP diagnosis in 44 patients, comprising 4.80% of patients with PaCa. Following a new diagnosis of CP, the risk of PaCa diagnosis was most marked in the first year (incidence 18.04 per 1,000 person-years (py), relative risk (RR) 63.43) and became similar to risk in patients with preexisting CP in the third year. The first-year incidence of PaCa was 7.33/1,000 py in the fifth decade and reached 36.91/1,000 py after seventh decade of life. Time to PaCa diagnosis following a CP diagnosis was ≤60 days in 14 patients, 3-12 months in 25 patients, and 13-24 months in 5 patients.
  
  
  CONCLUSIONS
  Approximately 5% of patients with PaCa are initially misdiagnosed as CP, and in two-thirds of these patients the cancer diagnosis is delayed by >2 months. PaCa should reliably be excluded before making a new CP diagnosis in patients who are >40 years old, especially in those without heavy smoking or alcohol history.
authors.affiliation: Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St Louis, Missouri, USA.
authors.forename: Satish
authors.initials: S
authors.lastname: Munigala
authors.affiliation: Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St Louis, Missouri, USA.
authors.forename: Fasiha
authors.initials: F
authors.lastname: Kanwal
authors.affiliation: 1] Veterans Affairs St Louis Health Care System, St Louis, Missouri, USA [2] Department of Biostatistics, Saint Louis University School of Public Health, St Louis, Missouri, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Xian
authors.affiliation: Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St Louis, Missouri, USA.
authors.forename: Banke
authors.initials: B
authors.lastname: Agarwal
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D050500:Pancreatitis, Chronic / Q000175:diagnosis* / Q000453:epidemiology; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D014728:Veterans