Use of circulating tumor cells (CTC) in peripheral blood of breast cancer patients before and after adjuvant chemotherapy to predict risk for relapse: The SUCCESS trial.

Abstract

1003 Background: The prognostic significance of CTCs in MBC has been demonstrated. We evaluated whether the presence of CTC before and after adjuvant chemotherapy increases the risk of subsequent relapse and death. Methods: We analyzed 23 mL of peripheral blood from 1,489 N+ and high risk N- breast cancer pts before and after adjuvant taxane based chemotherapy. CTC were assessed with the CellSearchSystem (Veridex, USA). After immunomagnetic enrichment with an anti-Epcam-antibody, cells were labelled with anti-Ck8/18/19 and anti-CD45 antibodies to distinguish between epithelial cells and leukocytes. Pts were followed for a median of 32 months. Results: In 9.4% of pts (n > 140) > 1 CTC was detected before the start of systemic treatment (median 1, range 1-827), while 8.7% (n > 129) presented with > 1 CTC (median 1, range 1-124) after chemotherapy. Pts with CTC before treatment had significantly more lymphnodes involved (p < 0.01), but no correlation to tumor size, grading and HR-Status could be found. 85 recurrences occurred and 33 pts died of their disease. The presence of > 1 CTC before treatment was a significant prognostic factor with respect to poor DFS (p < 0.0001) and OAS (p > 0.023), whereas the persistence of > 1 CTC after chemotherapy only predicted reduced DFS (p > 0.054; p > 0.154 for OAS). A significantly better DFS and OAS was detected between the groups with persistently negative CTC status compared to those with persistently positive CTC status (p > 0.0031 and p > 0.0187). More than 5 CTC were a significant indicator of poor prognosis for DFS and OAS at all time points. In multivariate analysis, > 1CTC before treatment was an independent predictor for OAS, > 1 CTC after treatment for DFS, while tumor size, lymph node involvement, grading and HR-status were relevant for both time points. Conclusions: We demonstrated the prognostic relevance of CTC in peripheral blood of early breast cancer pts before and after chemotherapy. Therefore, CTC detection could serve as clinically useful prognostic marker and treatment monitoring tool and should be tested as indicator for additional secondary adjuvant treatment intervention within clinical trials. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration AstraZeneca, Chugai Pharma, Lilly, Novartis, sanofi-aventis AstraZeneca, Chugai Pharma, Johnson & Johnson, Lilly, Novartis, sanofi-aventis