title: Meta-analysis of magnetic resonance imaging in detecting residual breast cancer after neoadjuvant therapy.
abstract: BACKGROUND
  It has been proposed that magnetic resonance imaging (MRI) be used to guide breast cancer surgery by differentiating residual tumor from pathologic complete response (pCR) after neoadjuvant chemotherapy. This meta-analysis examines MRI accuracy in detecting residual tumor, investigates variables potentially affecting MRI performance, and compares MRI with other tests.
  
  
  METHODS
  A systematic literature search was undertaken. Hierarchical summary receiver operating characteristic (HSROC) models were used to estimate (relative) diagnostic odds ratios ([R]DORs). Summary sensitivity (correct identification of residual tumor), specificity (correct identification of pCR), and areas under the SROC curves (AUCs) were derived. All statistical tests were two-sided.
  
  
  RESULTS
  Forty-four studies (2050 patients) were included. The overall AUC of MRI was 0.88. Accuracy was lower for "standard" pCR definitions (referent category) than "less clearly described" (RDOR = 2.41, 95% confidence interval [CI] = 1.11 to 5.23) or "near-pCR" definitions (RDOR = 2.60, 95% CI = 0.73 to 9.24; P = .03.) Corresponding AUCs were 0.83, 0.90, and 0.91. Specificity was higher when negative MRI was defined as contrast enhancement less than or equal to normal tissue (0.83, 95% CI = 0.64 to 0.93) vs no enhancement (0.54, 95% CI = 0.39 to 0.69; P = .02), with comparable sensitivity (0.83, 95% CI = 0.69 to 0.91; vs 0.87, 95% CI = 0.80 to 0.92; P = .45). MRI had higher accuracy than mammography (P = .02); there was only weak evidence that MRI had higher accuracy than clinical examination (P = .10). No difference in MRI and ultrasound accuracy was found (P = .15).
  
  
  CONCLUSIONS
  MRI accurately detects residual tumor after neoadjuvant chemotherapy. Accuracy was lower when pCR was more rigorously defined, and specificity was lower when test negativity thresholds were more stringent; these definitions require standardization. MRI is more accurate than mammography; however, studies comparing MRI and ultrasound are required.
authors.affiliation: Screening and Test Evaluation Program, Sydney School of Public Health, A27, Edward Ford Building, University of Sydney, NSW 2006, Australia. luke.marinovich@sydney.edu.au
authors.forename: Michael L
authors.initials: ML
authors.lastname: Marinovich
authors.forename: Nehmat
authors.initials: N
authors.lastname: Houssami
authors.forename: Petra
authors.initials: P
authors.lastname: Macaskill
authors.forename: Francesco
authors.initials: F
authors.lastname: Sardanelli
authors.forename: Les
authors.initials: L
authors.lastname: Irwig
authors.forename: Eleftherios P
authors.initials: EP
authors.lastname: Mamounas
authors.forename: Gunter
authors.initials: G
authors.lastname: von Minckwitz
authors.forename: Meagan E
authors.initials: ME
authors.lastname: Brennan
authors.forename: Stefano
authors.initials: S
authors.lastname: Ciatto
mesh_terms: D018943:Anthracyclines / Q000008:administration & dosage; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D019540:Area Under Curve; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000188:drug therapy; D018275:Carcinoma, Lobular / Q000175:diagnosis / Q000188:drug therapy; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008327:Mammography; D020360:Neoadjuvant Therapy / Q000379:methods; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000175:diagnosis*; D016017:Odds Ratio; D012372:ROC Curve; D012680:Sensitivity and Specificity; D043823:Taxoids / Q000008:administration & dosage; D000068878:Trastuzumab
chemical_list: D018943:Anthracyclines; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D043823:Taxoids; D000068878:Trastuzumab