title: Association of Regional Intensity of Ductal Carcinoma In Situ Treatment With Likelihood of Breast Preservation.
abstract: OBJECTIVE
  Large regional variation exists in the use of radiotherapy after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS). Although patients who do not receive initial radiotherapy for DCIS are candidates for subsequent BCS if they experience a second breast event, many undergo mastectomy instead.
  
  
  OBJECTIVE
  To examine whether regional practice patterns of radiotherapy for DCIS affect the use of mastectomy in these patients.
  
  
  METHODS
  A retrospective analysis of population-based databases (Surveillance, Epidemiology, and End Results [SEER] and SEER-Medicare). Data were obtained for 2679 women in SEER with a diagnosis of DCIS between 1990 and 2011 and for 757 women in SEER-Medicare with a DCIS diagnosis between 1991 and 2009 who had not undergone radiotherapy for DCIS and experienced a subsequent breast cancer or DCIS diagnosis.
  
  
  METHODS
  Treatment intensity for primary DCIS (high, medium, low), as defined by separating health service areas (HSAs) into 3 clusters based on radiotherapy use.
  
  
  METHODS
  Mastectomy vs BCS at a second breast event defined as DCIS recurrence or new invasive cancer.
  
  
  RESULTS
  The median (SD) ages of the participants was 64 (13) years for the 2679 SEER population and 79 (6) years for the SEER-Medicare cohort. Residence in an HSA characterized by greater radiotherapy use for DCIS increased the likelihood of receiving mastectomy vs BCS at a subsequent breast event, even among women who had not previously received radiotherapy for DCIS. Adjusted odds ratios for receiving mastectomy were 1.43 (95% CI, 1.10-1.85) and 1.90 (95% CI, 1.27-2.84) in SEER and SEER-Medicare databases, respectively, among women residing in an HSA with the greatest radiotherapy use vs the least, corresponding to an adjusted increase from 40.8% to 49.6%, and from 38.6% to 54.5%.
  
  
  CONCLUSIONS
  Areas with more radiotherapy use for DCIS had increased use of mastectomy at the time of a second breast event even among patients eligible for breast conservation. This association suggests that physician-related factors are affecting the likelihood of breast preservation.
authors.affiliation: Department of Radiation Therapy, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Rinaa S
authors.initials: RS
authors.lastname: Punglia
authors.affiliation: Division of Population Sciences, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Angel M
authors.initials: AM
authors.lastname: Cronin
authors.affiliation: Division of Population Sciences, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Hajime
authors.initials: H
authors.lastname: Uno
authors.affiliation: Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts.
authors.forename: Natasha K
authors.initials: NK
authors.lastname: Stout
authors.affiliation: The Dartmouth Institute, Geisel School of Medicine, Hanover, New Hampshire.
authors.forename: Elissa M
authors.initials: EM
authors.lastname: Ozanne
authors.affiliation: Wisconsin Surgical Outcomes Research Program, Department of Surgery, University of Wisconsin School of Medicine, Madison.
authors.forename: Caprice C
authors.initials: CC
authors.lastname: Greenberg
authors.affiliation: Dana-Farber/Harvard Center Breast Cancer Advocacy Group, Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Frank
authors.affiliation: Division of Population Sciences, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Deborah
authors.initials: D
authors.lastname: Schrag
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D006278:Medicare; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D010820:Physicians; D018426:SEER Program; D014481:United States