title: Breast-conserving surgery for breast cancer: patterns of care in a geographic region and estimation of potential applicability.
abstract: BACKGROUND
  It has been postulated that one of the rewards of breast cancer screening is the increased likelihood of receiving breast-conserving surgery. The recent wide application of screening mammography has led to an acceleration in the otherwise gradual shift toward smaller, earlier-stage breast cancer that has been occurring since the turn of the century.
  
  
  METHODS
  We examined data from patients with pathologically diagnosed breast cancers from all general hospitals in the state of Vermont for use of breast-conserving surgery by era (1975-1984 [n = 1,652] versus 1989-1990 [n = 683]), method of cancer detection, age, clinical tumor-node-metastases (cTNM) stage, pathologic size, and node status.
  
  
  RESULTS
  Cancers detected by mammography were 2% in 1975-1984 and 36% in 1989-1990. Invasive breast cancers < 2 cm maximum pathologic diameter were 34% in 1975-1984 and 50% in 1989-1990 (p < 0.001). Statewide, the use of breast-conserving surgery for invasive cancer increased from 8.6% in 1975-1984 to 42.9% in 1989-1990 (p < 0.001). In 1989-1990 at the single university hospital, 73% of the patients were treated with breast-conserving surgery versus 22% at the community hospitals (range 0-39%, p < 0.001). Differential referral patterns related to stage and age did not appear to explain the variation, because the percentages of cTNM stage I and II patients at the university hospital were similar to those of the community hospitals. Using the university hospital as the standard, we estimated that at least 67% of all patients in the state were eligible for breast-conserving surgery in the years 1975-1984 and 73% in the years 1975-1984, a 6% increase.
  
  
  CONCLUSIONS
  Most of the variation in breast-conserving surgery was related to factors other than patient age and stage of disease. Variation was probably related more to local community factors and physician attitudes. At least two-thirds of the women in the state were eligible for breast-conserving surgery even before the wide use of mammography screening.
authors.affiliation: Vermont Cancer Center, Burlington, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Foster
authors.forename: M E
authors.initials: ME
authors.lastname: Farwell
authors.forename: M C
authors.initials: MC
authors.lastname: Costanza
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000601:surgery*; D016009:Chi-Square Distribution; D005260:Female; D006764:Hospitals, Community; D006785:Hospitals, University; D006801:Humans; D008197:Lymph Node Excision; D008327:Mammography / Q000706:statistics & numerical data*; D015412:Mastectomy, Segmental / Q000706:statistics & numerical data*; D008499:Medical Records; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012042:Registries; D012189:Retrospective Studies; D014707:Vermont / Q000453:epidemiology