title: I-123-MIBG myocardial imaging in trastuzumab-based cardiotoxicity:  the first experience.
abstract: BACKGROUND
  Cardiotoxicity related to trastuzumab anticancer treatment poses a diagnostic challenge at early stages. The aim of the present pilot study was to assess the value of iodine-123-metaiodobenzylguanidine (I-123-MIBG) scintigraphy in breast cancer patients treated with trastuzumab who showed a decrease in their cardiac function.
  
  
  METHODS
  I-123-MIBG scintigraphy was performed in nine patients with decreased or significantly decreasing left ventricular ejection fraction (LVEF) during trastuzumab therapy. On the basis of planar images, 4 h heart-to-mediastinum (HMR) ratio and washout percentages (WR) were calculated.
  
  
  RESULTS
  I-123-MIBG scintigraphy revealed abnormal 4 h HMR and increased WR in three patients. LVEF recovery was observed in none of these patients during 3, 6, and 13 months of follow-up. In two of five patients with normal 4 h HMR the washout rates were also normal, whereas in three patients slightly increased washout rates were found. All five patients demonstrated a recovery of their LVEF value during follow-up. One patient with a normal 4 h HMR and normal WR initially showed a significant decrease in LVEF, which decreased further during follow-up. However, the LVEF value remained at 53%, which was within normal limits, after trastuzumab administration.
  
  
  CONCLUSIONS
  In this pilot study we have explored the role of I-123-MIBG scintigraphy in the assessment of trastuzumab-related cardiotoxicity and suggest that, in patients with a persistently decreasing LVEF, I-123-MIBG scintigraphy might indicate whether recovery will occur and, consequently, whether retreatment may be initiated.
authors.affiliation: Department of Nuclear Medicine, The Netherlands Cancer Institute, Amsterdam, The Netherlands. m.stokkel@nki.nl
authors.forename: Marcel P M
authors.initials: MP
authors.lastname: Stokkel
authors.forename: Linda J
authors.initials: LJ
authors.lastname: de Wit-van der Veen
authors.forename: Annelies
authors.initials: A
authors.lastname: Boekhout
mesh_terms: D019797:3-Iodobenzylguanidine; D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects* / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000503:physiopathology; D054715:Cardiotoxins / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011877:Radionuclide Imaging; D000068878:Trastuzumab
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D054715:Cardiotoxins; D007457:Iodine Radioisotopes; D019797:3-Iodobenzylguanidine; D000068878:Trastuzumab