title: Pathogenesis and progression of oesophageal adenocarcinoma varies by prior diagnosis of Barrett's oesophagus.
abstract: BACKGROUND
  The absolute risk of oesophageal adenocarcinoma (EA) among individuals with Barrett's oesophagus (BE) is low and a majority of EA cases are diagnosed among individuals with no prior BE diagnosis. To ensure that insights from EA case-control studies are transferable to clinical management of BE populations, we conducted a case-case study to compare the clinical presentation, medical history and survival of EA cases with and without a prior BE diagnosis in the Surveillance, Epidemiology and End Results Medicare database.
  
  
  METHODS
  Eligible EA cases were diagnosed at age ⩾68 years during 1994-2009. There were 5271 EA cases in this study, 87% of which did not have a prior diagnosis of BE (EA-no prior BE).
  
  
  RESULTS
  Multivariable case-case comparisons evidenced adverse associations of GERD, ever cigarette smoking, hypertension, dyslipidemia, weight loss, peptic ulcer and irritable bowel disease each in EA-prior BE compared with EA-no prior BE. Obesity, metabolic syndrome, impaired fasting glucose and diabetes did not differ between groups. EA-prior BE cases were diagnosed with less advanced disease, were more likely to undergo surgery and less likely to receive chemotherapy and radiotherapy, and had better overall mean survival (2.5 vs 1.4 years). This survival advantage persisted in the multivariable Cox model (HR=0.69, 95%CI: 0.60, 0.78), despite adjustment for many factors including stage, grade and clinical interventions.
  
  
  CONCLUSIONS
  This study provides evidence that EA cases occurring among individuals previously diagnosed with BE are different from the large majority of EA cases that occur without a prior BE diagnosis. Regardless of whether these differences emanate from aetiology, biology and/or selection biases, they underscore the importance of a prudent approach in using knowledge from EAC case-control studies in the management of BE populations.
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD 20850, USA.
authors: Michael B
authors: MB
authors: Cook
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD 20850, USA.
authors: Jennifer
authors: J
authors: Drahos
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD 20850, USA.
authors: Shannon
authors: S
authors: Wood
authors: Division of Cancer Control and Population Sciences, National Cancer Institute, NIH, DHHS, Rockville, MD 20850, USA.
authors: Lindsey
authors: L
authors: Enewold
authors: Information Management Services, Rockville, MD 20852, USA.
authors: Ruth
authors: R
authors: Parsons
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD 20850, USA.
authors: Neal D
authors: ND
authors: Freedman
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD 20850, USA.
authors: Philip R
authors: PR
authors: Taylor
authors: Information Management Services, Rockville, MD 20852, USA.
authors: Winnie
authors: W
authors: Ricker
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD 20850, USA.
authors: Christian C
authors: CC
authors: Abnet
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000368:Aged; D001471:Barrett Esophagus / Q000175:diagnosis*; D004938:Esophageal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models