title: Association of ampullary and colorectal malignancies.
abstract: BACKGROUND
  Because of the similarities in terms of carcinogenesis and natural history between cancer of the ampulla of Vater and colorectal cancer, the authors examined whether ampullary and colorectal malignancies occur in the same individuals at increased rates.
  
  
  METHODS
  We used data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute for the period from January 1973 through December 1999. Person-years of follow-up for patients with ampullary (or colorectal) cancer were used to calculate the expected number of cases of colorectal (or ampullary) cancer as a second primary malignancy. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were calculated using Byar limits and assuming a Poisson distribution.
  
  
  RESULTS
  The authors identified 2043 white patients with ampullary cancer who were included in the SEER registry between 1973 and 1999. Over an aggregate 5674 person-years of follow-up, 30 patients, compared with an expected 14, developed colorectal cancer, yielding an overall SIR of 2.14 (95% CI, 1.45-3.06). Similarly, 57 of 262,066 white patients with colorectal cancer developed ampullary cancer over an aggregate 1,270,255 person-years of follow-up, yielding an SIR of 2.18 (95% CI, 1.69-2.85).
  
  
  CONCLUSIONS
  Patients with ampullary cancer are at increased risk for a second primary colorectal malignancy, and patients with colorectal cancer are at increased risk for a second primary ampullary malignancy. These findings suggest that ampullary and colorectal malignancies share common environmental and/or genetic risk factors.
authors.affiliation: Division of Gastroenterology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Ananya
authors.initials: A
authors.lastname: Das
authors.forename: Alfred I
authors.initials: AI
authors.lastname: Neugut
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Cooper
authors.forename: Amitabh
authors.initials: A
authors.lastname: Chak
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D014670:Ampulla of Vater / Q000473:pathology*; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D003138:Common Bile Duct Neoplasms / Q000453:epidemiology* / Q000556:secondary* / Q000628:therapy; D015897:Comorbidity; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011336:Probability; D011379:Prognosis; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution; D016019:Survival Analysis; D016896:Treatment Outcome