title: Diagnostic breast magnetic resonance imaging and contralateral prophylactic mastectomy.
abstract: BACKGROUND
  Preoperative use of breast magnetic resonance imaging (MRI) in women with breast cancer may increase rates of mastectomy. This study investigated relationships between breast MRI and therapeutic and contralateral prophylactic mastectomy (CPM) in women with breast cancer.
  
  
  METHODS
  A total of 3606 women diagnosed with stage 0-III breast cancer from 1998 through 2000 (n = 1743; early period) or from 2003 through 2005 (n = 1863; late period) were retrospectively identified. Patient demographic and clinical characteristics were obtained from our institution's tumor registry. MRI use in the diagnostic evaluation was obtained from a prospective radiology database. Rates of therapeutic mastectomy, CPM, and associations with breast MRI were compared between the two time periods by multiple logistic regressions controlling for disease stage, age, family history, and calendar year of diagnosis.
  
  
  RESULTS
  A total of 14.2% of women underwent MRI, 29.0% had mastectomy, and 5.3% had CPM. Use of breast MRI increased substantially between the two time periods (4.1% to 23.7%, P < 0.001). Mastectomy rates increased from 28% to 30% (P > 0.05). The rate of CPM increased by >50% from the early to late period (4.1% to 6.4%, P < 0.002). Women who underwent MRI were nearly twice as likely to have CPM (9.2 vs. 4.7%, P < 0.001). Multivariate models found MRI was associated with increased rates of CPM for women with stage I or II disease (odds ratio 2.04, P = 0.001).
  
  
  CONCLUSIONS
  MRI changes the surgical treatment of breast cancer among subsets of women diagnosed with breast cancer, suggesting there are hidden monetary and nonmonetary costs associated with its use.
authors.affiliation: RAND Corporation, Pittsburgh, PA, USA. msorbero@rand.org
authors.forename: Melony E S
authors.initials: ME
authors.lastname: Sorbero
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Dick
authors.forename: Ellen Burke
authors.initials: EB
authors.lastname: Beckjord
authors.forename: Gretchen
authors.initials: G
authors.lastname: Ahrendt