title: Magnetic resonance imaging screening of the contralateral breast in women with newly diagnosed breast cancer: systematic review and meta-analysis of incremental cancer detection and impact on surgical management.
abstract: OBJECTIVE
  Preoperative magnetic resonance imaging (MRI) is increasingly used for staging women with breast cancer, including screening for occult contralateral cancer. This article is a review and meta-analysis of studies reporting contralateral MRI in women with newly diagnosed invasive breast cancer.
  
  
  METHODS
  We systematically reviewed the evidence on contralateral MRI, calculating pooled estimates for positive predictive value (PPV), true-positive:false-positive ratio (TP:FP), and incremental cancer detection rate (ICDR) over conventional imaging. Random effects logistic regression examined whether estimates were associated with study quality or clinical variables.
  
  
  RESULTS
  Twenty-two studies reported contralateral malignancies detected only by MRI in 131 of 3,253 women. Summary estimates were as follows: MRI-detected suspicious findings (TP plus FP), 9.3% (95% CI, 5.8% to 14.7%); ICDR, 4.1% (95% CI, 2.7% to 6.0%), PPV, 47.9% (95% CI, 31.8% to 64.6%); TP:FP ratio, 0.92 (95% CI, 0.47 to 1.82). PPV was associated with the number of test positives and baseline imaging. Few studies included consecutive women, and few ascertained outcomes in all subjects. Where reported, 35.1% of MRI-detected cancers were ductal carcinoma in situ (mean size = 6.9 mm), 64.9% were invasive cancers (mean size = 9.3 mm), and the majority were stage pTis or pT1 and node negative. Effect on treatment was inconsistently reported, but many women underwent contralateral mastectomy.
  
  
  CONCLUSIONS
  MRI detects contralateral lesions in a substantial proportion of women, but does not reliably distinguish benign from malignant findings. Relatively high ICDR may be due to selection bias and/or overdetection. Women must be informed of the uncertain benefit and potential harm, including additional investigations and surgery.
authors.affiliation: Screening and Test Evaluation Program, School of Public Health, Faculty of Medicine, and National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Sydney, Australia.
authors.forename: Meagan Elizabeth
authors.initials: ME
authors.lastname: Brennan
authors.forename: Nehmat
authors.initials: N
authors.lastname: Houssami
authors.forename: Sarah
authors.initials: S
authors.lastname: Lord
authors.forename: Petra
authors.initials: P
authors.lastname: Macaskill
authors.forename: Les
authors.initials: L
authors.lastname: Irwig
authors.forename: J Michael
authors.initials: JM
authors.lastname: Dixon
authors.forename: Ruth M L
authors.initials: RM
authors.lastname: Warren
authors.forename: Stefano
authors.initials: S
authors.lastname: Ciatto
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology* / Q000601:surgery; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000601:surgery*; D015331:Cohort Studies; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008403:Mass Screening / Q000379:methods*; D008408:Mastectomy / Q000379:methods; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D016609:Neoplasms, Second Primary / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016019:Survival Analysis