PT  - JOURNAL ARTICLE
AU  - Joanne E. Mortimer
AU  - James R. Bading
AU  - Jinha M. Park
AU  - Paul H. Frankel
AU  - Mary I. Carroll
AU  - Tri T. Tran
AU  - Erasmus K. Poku
AU  - Russell C. Rockne
AU  - Andrew A. Raubitschek
AU  - John E. Shively
AU  - David M. Colcher
TI  - Tumor Uptake of <sup>64</sup>Cu-DOTA-Trastuzumab in Patients with Metastatic Breast Cancer
AID  - 10.2967/jnumed.117.193888
DP  - 2018 Jan 01
TA  - Journal of Nuclear Medicine
PG  - 38--43
VI  - 59
IP  - 1
4099  - http://jnm.snmjournals.org/content/59/1/38.short
4100  - http://jnm.snmjournals.org/content/59/1/38.full
SO  - J Nucl Med2018 Jan 01; 59
AB  - The goal of this study was to characterize the relationship between tumor uptake of 64Cu-DOTA-trastuzumab as measured by PET/CT and standard, immunohistochemistry (IHC)-based, histopathologic classification of human epidermal growth factor receptor 2 (HER2) status in women with metastatic breast cancer (MBC). Methods: Women with biopsy-confirmed MBC and not given trastuzumab for 2 mo or more underwent complete staging, including 18F-FDG PET/CT. Patients were classified as HER2-positive (HER2+) or -negative (HER2−) based on fluorescence in situ hybridization (FISH)–supplemented immunohistochemistry of biopsied tumor tissue. Eighteen patients underwent 64Cu-DOTA-trastuzumab injection, preceded in 16 cases by trastuzumab infusion (45 mg). PET/CT was performed 21–25 (day 1) and 47–49 (day 2) h after 64Cu-DOTA-trastuzumab injection. Radiolabel uptake in prominent lesions was measured as SUVmax. Average intrapatient SUVmax (<SUVmax>pt) was compared between HER2+ and HER2− patients. Results: Eleven women were HER2+ (8 immunohistochemistry 3+; 3 immunohistochemistry 2+/FISH amplified), whereas 7 were HER2− (3 immunohistochemistry 2+/FISH nonamplified; 4 immunohistochemistry 1+). Median <SUVmax>pt for day 1 and day 2 was 6.6 and 6.8 g/mL for HER 2+ and 3.7 and 4.3 g/mL for HER2− patients (P < 0.005 either day). The distributions of <SUVmax>pt overlapped between the 2 groups, and interpatient variability was greater for HER2+ than HER2− disease (P < 0.005 and 0.001, respectively, on days 1 and 2). Conclusion: By 1 d after injection, uptake of 64Cu-DOTA-trastuzumab in MBC is strongly associated with patient HER2 status and is indicative of binding to HER2. The variability within and among HER2+ patients, as well as the overlap between the HER2+ and HER2− groups, suggests a role for 64Cu-DOTA-trastuzumab PET/CT in optimizing treatments that include trastuzumab.