title: Prospective study of breast cancer incidence in women with a BRCA1 or BRCA2 mutation under surveillance with and without magnetic resonance imaging.
abstract: OBJECTIVE
  The sensitivity of magnetic resonance imaging (MRI) for breast cancer screening exceeds that of mammography. If MRI screening reduces mortality in women with a BRCA1 or BRCA2 mutation, it is expected that the incidence of advanced-stage breast cancers should be reduced in women undergoing MRI screening compared with those undergoing conventional screening.
  
  
  METHODS
  We followed 1,275 women with a BRCA1 or BRCA2 mutation for a mean of 3.2 years. In total, 445 women were enrolled in an MRI screening trial in Toronto, Ontario, Canada, and 830 were in the comparison group. The cumulative incidences of ductal carcinoma in situ (DCIS), early-stage, and late-stage breast cancers were estimated at 6 years in the cohorts.
  
  
  RESULTS
  There were 41 cases of breast cancer in the MRI-screened cohort (9.2%) and 76 cases in the comparison group (9.2%). The cumulative incidence of DCIS or stage I breast cancer at 6 years was 13.8% (95% CI, 9.1% to 18.5%) in the MRI-screened cohort and 7.2% (95% CI, 4.5% to 9.9%) in the comparison group (P = .01). The cumulative incidence of stages II to IV breast cancers was 1.9% (95% CI, 0.2% to 3.7%) in the MRI-screened cohort and 6.6% (95% CI, 3.8% to 9.3%) in the comparison group (P = .02). The adjusted hazard ratio for the development of stages II to IV breast cancer associated with MRI screening was 0.30 (95% CI, 0.12 to 0.72; P = .008).
  
  
  CONCLUSIONS
  Annual surveillance with MRI is associated with a significant reduction in the incidence of advanced-stage breast cancer in BRCA1 and BRCA2 carriers.
authors: Sunnybrook Odette Cancer Centre, Women's College Research Institute, 790 Bay St, Toronto, Ontario, M5G 1N8, Canada.
authors: Ellen
authors: E
authors: Warner
authors: Kimberley
authors: K
authors: Hill
authors: Petrina
authors: P
authors: Causer
authors: Donald
authors: D
authors: Plewes
authors: Roberta
authors: R
authors: Jong
authors: Martin
authors: M
authors: Yaffe
authors: William D
authors: WD
authors: Foulkes
authors: Parviz
authors: P
authors: Ghadirian
authors: Henry
authors: H
authors: Lynch
authors: Fergus
authors: F
authors: Couch
authors: John
authors: J
authors: Wong
authors: Frances
authors: F
authors: Wright
authors: Ping
authors: P
authors: Sun
authors: Steven A
authors: SA
authors: Narod
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics / Q000473:pathology; D055088:Early Detection of Cancer; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009154:Mutation