P1-14-02: Correlation of Circulating Tumor Cells (CTC) and Circulating Endothelial Cells (CEC) with Pathological Complete Response (pCR) during Neoadjuvant Chemotherapy (CT) Combined with Bevacizumab in HER2 Negative Inflammatory Breast Cancer (IBC): Ancillary Study of Phase II Trial BEVERLY 1.

Abstract

Abstract Background: Prognostic value of CTC detection in blood has been reported in primary breast cancer with a rate around 20% in the neoadjuvant setting. No correlation between CTC and pCR to neoadjuvant CT in operable breast cancer has been reported (Pierga CCR 2008, Riethdorf CCR 2010). Predictive value of CEC for response to anti-angiogenic agents is unclear. Methods: CTC and CEC were detected in 7.5 ml and 4 ml of blood respectively with CellSearch™ System in the neoadjuvant setting of HER2 negative IBC (T4d) patients (pts) enrolled in the phase II multicentre trial BEVERLY 1, evaluating bevacizumab (15mg/kg q3w) in combination with sequential neoadjuvant CT of 4 cycles of FEC followed by 4 cycles of Docetaxel. Patients received postoperatively 10 cycles of bevacizumab and hormonotherapy if tumor was ER+. Results: From 12/08 to 09/10, 101 pts were included, 96 were evaluable for pCR and 92 for CTC and CEC. Out of 96 pts, 51 (53%) had triple negative breast cancer (TNBC). At baseline, 37 pts out of 92 had ≥ 1 detectable CTC (40%, 95%CI 30–50%). At baseline, CTC level was not correlated with CEC level, neither with TNBC nor pCR. A drop in CTC incidence was observed from baseline to the 1st follow-up analysis after 4 cycles (p<0.0001). Out of 6 pts with detectable CTC at the end of adjuvant bevacizumab (8 months post surgery) none had pCR (p=0.05 Yates test). There was a significant increase of CEC from baseline to presurgery sample (p <0.001) and a decrease (p=0.04) after tumor removal and end of CT. A higher level of CEC (>20/4ml) before C5 could be associated with a higher probability of pCR (Khi2 test, p=0.003). Conclusions: We observed a high CTC detection rate of 40% in HER2− IBC, including TNBC. CEC levels increased progressively during neoadjuvant treatment and decreased after its interruption. Baseline CTC and CEC levels were not predictive of pCR. Detection of CTC at 8 months of follow-up was associated with the absence of response to neoadjuvant chemotherapy. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-14-02.