Clinical trial

Breast Cancer Research and Treatment

, Volume 124, Issue 2, pp 403-412

HER2 status of circulating tumor cells in patients with metastatic breast cancer: a prospective, multicenter trial

  • Tanja FehmAffiliated withDepartment of Gynecology and Obstetrics, University of Tübingen Email author 
  • , Volkmar MüllerAffiliated withDepartment of Gynecology, University Medical Center Hamburg-Eppendorf
  • , Bahriye AktasAffiliated withDepartment of Gynecology and Obstetrics, University Hospital of Essen
  • , Wolfgang JanniAffiliated withDepartment of Gynecology and Obstetrics, University of Düsseldorf
  • , Andreas SchneeweissAffiliated withDepartment of Gynecology and Obstetrics, University of Heidelberg
  • , Elmar StickelerAffiliated withDepartment of Gynecology and Obstetrics, University of Freiburg
  • , Claus LattrichAffiliated withDepartment of Gynecology and Obstetrics, University of Regensburg
  • , Christian R. LöhbergAffiliated withDepartment of Gynecology and Obstetrics, University of Erlangen
  • , Erich SolomayerAffiliated withDepartment of Gynecology and Obstetrics, University of Homburg
    • , Brigitte RackAffiliated withDepartment of Gynecology and Obstetrics, University of TübingenDepartment of Gynecology and Obstetrics, University of Munich
    • , Sabine RiethdorfAffiliated withDepartment of Gynecology and Obstetrics, University of TübingenInstitute of Tumor Biology, University Medical Center Hamburg-Eppendorf
    • , Christoph KleinAffiliated withDepartment of Gynecology and Obstetrics, University of TübingenInstitute of Pathology, Division of Oncogenomics, University of Regensburg
    • , Christian SchindlbeckAffiliated withDepartment of Gynecology and Obstetrics, University of TübingenDepartment of Gynecology and Obstetrics, University of Munich
    • , Kerstin BrockerAffiliated withDepartment of Gynecology and Obstetrics, University of Heidelberg
    • , Sabine Kasimir-BauerAffiliated withDepartment of Gynecology and Obstetrics, University Hospital of Essen
    • , Diethelm WallwienerAffiliated withDepartment of Gynecology and Obstetrics, University of Tübingen
    • , Klaus PantelAffiliated withDepartment of Gynecology and Obstetrics, University of TübingenInstitute of Tumor Biology, University Medical Center Hamburg-Eppendorf

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Abstract

There is a growing body of evidence that HER2 status can change during disease recurrence or progression in breast cancer patients. In this context, re-evaluation of HER2 status by assessment of HER2 expression on circulating tumor cells (CTCs) is a strategy with potential clinical application. The aim of this trial was to determine the HER2 status of CTCs in metastatic breast cancer patients comparing two CTC assays. A total of 254 patients with metastatic breast cancer from nine German university breast cancer centers were enrolled in this prospective study. HER2 status of CTCs was assessed using both the FDA-approved CellSearch® assay and AdnaTest BreastCancer™. Using the CellSearch assay, 122 of 245 (50%) patients had ≥5 CTCs, and HER2-positive CTCs were observed in 50 (41%) of these patients. Ninety of 229 (39%) patients were CTC positive using AdnaTest BreastCancer, and HER2 positivity rate was 47% (42 of 90). The rate of breast cancer patients with HER2-negative primary tumors but HER2-positive CTCs was 32% (25 of 78) and 49% (28 of 57) using the CellSearch assay and AdnaTest BreastCancer, respectively. Considering only those patients who had CTCs on both tests (n = 62), concordant results regarding HER2 positivity were obtained in 50% of the patients (31/62) (P = 0.96, κ = −0.006). HER2-positive CTCs can be detected in a relevant number of patients with HER2 negative primary tumors. Therefore, it will be mandatory to correlate the assay-dependent HER2 status of CTCs to the clinical response on HER2-targeted therapies.

Keywords

Breast cancer Circulating tumor cells HER2 Metastasis