title: Radiation therapy for breast cancer and increased risk for esophageal carcinoma.
abstract: BACKGROUND
  Several case reports have suggested an association between radiation therapy for breast cancer and the subsequent occurrence of esophageal carcinomas.
  
  
  OBJECTIVE
  To examine the association between radiation therapy for breast cancer and subsequent esophageal squamous-cell carcinomas and adenocarcinomas.
  
  
  METHODS
  Population-based retrospective cohort study.
  
  
  METHODS
  Population-based U.S. cancer registries.
  
  
  METHODS
  220,806 women in whom breast cancer was diagnosed between 1 January 1973 and 31 December 1993; 1,216,853 person-years of follow-up.
  
  
  METHODS
  Age- and period-adjusted standardized incidence ratio as a measure of relative risk for the second primary cancer.
  
  
  RESULTS
  In women who had received radiation therapy for breast cancer, the relative risk for esophageal squamous-cell carcinoma increased to 5.42 (95% CI, 2.33 to 10.68) and the relative risk for esophageal adenocarcinoma increased to 4.22 (CI, 0.47 to 15.25) 10 or more years after radiation therapy. No increased risk was seen for either type of carcinoma among patients with breast cancer who did not receive radiation therapy.
  
  
  CONCLUSIONS
  The risk for esophageal carcinoma is increased in women who receive radiation therapy for breast cancer.
authors.forename: H
authors.initials: H
authors.lastname: Ahsan
authors.forename: A I
authors.initials: AI
authors.lastname: Neugut
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000209:etiology*; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D004938:Esophageal Neoplasms / Q000209:etiology*; D005260:Female; D006801:Humans; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D011878:Radiotherapy / Q000009:adverse effects; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors