title: Magnetic resonance examination to predict pathological complete response following neoadjuvant chemotherapy: when is it appropriate for HER2-positive and triple-negative breast cancers?
abstract: BACKGROUND
  To clarify appropriate timing for magnetic resonance examination to predict pathological complete response to neoadjuvant chemotherapy for patients with human epidermal growth factor receptor 2 (HER2)-positive and triple-negative breast cancers in terms of tumor volume change.
  
  
  METHODS
  Between September 2009 and December 2014, 113 women with HER2-positive (n = 51) and triple-negative (n = 62) invasive breast cancers undergoing neoadjuvant chemotherapy were enrolled. Patients with HER2-positive tumors underwent neoadjuvant chemotherapy with an anthracycline-based regimen followed by docetaxel with trastuzumab. Patients with triple-negative tumors underwent neoadjuvant chemotherapy with anthracycline-based (first in most cases) and taxane-based regimens. Magnetic resonance imaging was performed before neoadjuvant chemotherapy, between the regimens (midpoint examination), and after neoadjuvant chemotherapy (final examination). Response ratio of tumor volume was calculated and receiver-operating characteristic analyses for them for both subtypes were performed at the midpoint and final examinations.
  
  
  RESULTS
  Twenty-eight women with HER2-positive tumors (54.9 %) and 29 women with triple-negative tumors (46.8 %) had pathological complete response. The response ratios were better in cases with pathological complete response than in those without (p = 0.0341, p < 0.0001). The area under the curve at the final examination was higher than that at the midpoint examination for HER2-positive tumors (p = 0.039); whereas for the triple-negative tumors, no significant difference between the two examinations was shown (p = 0.5218).
  
  
  CONCLUSIONS
  Magnetic resonance examination to predict pathological complete response would be feasible after completion of a regimen including trastuzumab for HER2-positive tumors and at the midpoint of neoadjuvant chemotherapy for triple-negative tumors.
authors.affiliation: Department of Radiology, Breast and Imaging Center, St. Marianna University School of Medicine, 6-7-2 Manpukuji, Asao-ku, Kawasaki, Kanagawa, 215-0004, Japan. satoko.o@marianna-u.ac.jp.
authors.forename: Satoko
authors.initials: S
authors.lastname: Okamoto
authors.affiliation: Department of Radiology, Yokohama City Seibu Hospital, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Department of Radiology, Breast and Imaging Center, St. Marianna University School of Medicine, 6-7-2 Manpukuji, Asao-ku, Kawasaki, Kanagawa, 215-0004, Japan.
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Kanemaki
authors.affiliation: Department of Breast Surgical Oncology, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kojima
authors.affiliation: Department of Breast Surgical Oncology, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsugawa
authors.affiliation: Department of Radiology, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nakajima
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D012189:Retrospective Studies; D000068878:Trastuzumab / Q000008:administration & dosage; D016896:Treatment Outcome; D064726:Triple Negative Breast Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human
keywords: HER2-positive; Magnetic response imaging; Neoadjuvant chemotherapy; Pathological complete response; Triple-negative