title: Breast cancer molecular phenotype and the use of HER2-targeted agents influence the accuracy of breast MRI after neoadjuvant chemotherapy.
abstract: OBJECTIVE
  To investigate whether the accuracy of magnetic resonance imaging (MRI) after neoadjuvant systemic therapy (NST) is affected by molecular features of primary breast cancer and the use of human epidermal growth factor receptor 2 (HER2)-targeted agents.
  
  
  BACKGROUND
  Improved understanding of factors affecting the accuracy of breast MRI after NST can lead to more tailored use of MRI in deciding surgical extent after NST.
  
  
  METHODS
  We analyzed the imaging and clinicopathological data of 463 patients who underwent NST. We aimed to investigate whether the molecular subtypes, and the use of targeted therapies, were associated with changes in the accuracy of MRI predicting residual tumor extent.
  
  
  RESULTS
  The accuracy of MRI predicting the residual tumor extent was most accurate in triple-negative breast cancer and was least accurate in Luminal A subtype (Pearson correlation coefficient of 0.754 and 0.531, respectively). Multivariate analysis suggested estrogen receptor (ER) status as an independent factor influencing the MRI accuracy. In HER2-amplified tumors, the use of HER2-targeted agents was associated with a less accurate MRI prediction.
  
  
  CONCLUSIONS
  The accuracy of MRI in predicting residual tumor extent was lowest in ER-positive tumors treated with NST. In HER2-positive tumors, the use of HER2-targeted agents resulted in a less accurate MRI after NST. These factors should be considered for deciding the extent of breast conservation after neoadjuvant chemotherapy.
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul National University Hospital, South Korea.
authors.forename: Hyeong-Gon
authors.initials: HG
authors.lastname: Moon
authors.forename: Wonshik
authors.initials: W
authors.lastname: Han
authors.forename: Soo Kyung
authors.initials: SK
authors.lastname: Ahn
authors.forename: Nariya
authors.initials: N
authors.lastname: Cho
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Moon
authors.forename: Seock-Ah
authors.initials: SA
authors.lastname: Im
authors.forename: In Ae
authors.initials: IA
authors.lastname: Park
authors.forename: Dong-Young
authors.initials: DY
authors.lastname: Noh
mesh_terms: D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008408:Mastectomy; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D010641:Phenotype; D011300:Preoperative Care; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D000068878:Trastuzumab
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D000068878:Trastuzumab; C508053:ERBB2 protein, human; C485206:pertuzumab