Prognostic impact of circulating tumor cells assessed with the CellSearch System™ and AdnaTest Breast™ in metastatic breast cancer patients: the DETECT study
- Equal contributors
1 Department of Gynecology, University Medical Center Hamburg-Eppendorf, Martnistrasse 52, 20246 Hamburg, Germany
2 Department of Tumor Biology, University Medical Center Hamburg-Eppendorf, Martnistrasse 52, 20246 Hamburg, Germany
3 Department of Obstetrics and Gynecology, LMU, Maistrasse 11, 80337 Munich, Germany
4 Department of Obstetrics and Gynecology, University Medical Center, Moorenstraße 5, 40225 Düsseldorf, Germany
5 University Breast Center Franconia, Department of Gynecology and Obstetrics, Friedrich-Alexander University Erlangen-Nuremberg, Comprehensive Cancer Center Erlangen-Nuremberg, Universitätsstraße 21, 91054 Erlangen, Germany
6 Department of Obstetrics and Gynecology, University Medical Center, Kirrberger Strasse 1, 66421 Homburg/Saar, Germany
7 Department of Obstetrics and Gynecology, University Medical Center, Hufelandstrasse 55, 45147 Essen, Germany
8 Department of Obstetrics and Gynecology, University Medical Center, Calwer Strasse 7, 72076 Tübingen, Germany
Breast Cancer Research 2012, 14:R118 doi:10.1186/bcr3243Published: 15 August 2012
There is a multitude of assays for the detection of circulating tumor cells (CTCs) but a very limited number of studies comparing the clinical relevance of results obtained with different test methods. The DETECT trial for metastatic breast cancer patients was designed to directly compare the prognostic impact of two commercially available CTC assays that are prominent representatives of immunocytochemical and RT-PCR based technologies.
In total, 254 metastatic breast cancer patients were enrolled in this prospective multicenter trial. CTCs were assessed using both the AdnaTest Breast Cancer and the CellSearch system according to the manufacturers' instructions.
With the CellSearch system, 116 of 221 (50%) evaluable patients were CTC-positive based on a cut-off level at 5 or more CTCs. The median overall survival (OS) was 18.1 months in CTC-positive patients. (95%-CI: 15.1-22.1 months) compared to 27 months in CTC-negative patients (23.5-30.7 months; p<0.001). This prognostic impact for OS was also significant in the subgroups of patients with triple negative, HER2-positive and hormone receptor-positive/HER2-negative primary tumors. The progression free survival (PFS) was not correlated with CTC status in our cohort receiving different types and lines of systemic treatment (p = 0.197). In multivariate analysis, the presence of CTCs was an independent predictor for OS (HR: 2.7, 95%-CI: 1.6-4.2). When the AdnaTest Breast was performed, 88 of 221 (40%) patients were CTC-positive. CTC-positivity assessed by the AdnaTest Breast had no association with PFS or OS.
The prognostic relevance of CTC detection in metastatic breast cancer patients depends on the test method. The present results indicate that the CellSearch system is superior to the AdnaTest Breast Cancer in predicting clinical outcome in advanced breast cancer.
Current Controlled Trials Registry number ISRCTN59722891.