Abstract P2-01-04: Long term independent prognostic impact of circulating tumor cells detected before neoadjuvant chemotherapy in non-metastatic breast cancer: 70 months analysis of the REMAGUS02 study

Background: Circulating tumor cells (CTCs) isolated by CellSearch ® from peripheral blood of metastatic breast patients have been shown as strong independent prognostic factor for progression-free and overall survival. With this technique, the REMAGUS02 prospective multicentric study was the first to report that CTC detection (≥1CTC/7.5ml) before and/or after neoadjuvant chemotherapy was independently associated with distant metastasis-free survival (DMFS, 18 months follow-up, Pierga CCR 2008) and with overall survival (OS, 36 months follow-up, Bidard Ann Oncol 2010). Patients and Methods: In 115 non-metastatic patients diagnosed with large operable or locally advanced breast cancer, we prospectively detected CTC using the CellSearch system before and after neoadjuvant chemotherapy in the REMAGUS02 trial (Pierga, BCRT 2010). For this report, survival analyses were performed at a median follow-up of 70 months. Results: After a median follow-up of 70 months, 20 distant metastatic relapses and 14 deaths have been observed among the 115 patients included. CTC detection before chemotherapy (in 23% of patients) is an independent prognostic factor for both DMFS [p = 0.03, relative risk (RR)=3.2] and OS [p = 0.05, RR = 3.7] in multivariate analyses, together with triple negative tumor status. At long-term, CTC detection after chemotherapy (17%) had no clear prognostic significance (p = 0.15 and 0.22, respectively). Complete pathological response as well as tumour size and all other variables tested did not appear as predictive in this model. Conclusions: Baseline CTC detection is a new independent prognostic factor in the neoadjuvant setting, and is, in this trial, superior to pathological tumor response to predict the survival of non-metastatic breast cancer patients. We confirm therefore our previous results reported with shorter follow-up. Supported by PHRC AOM/2OO2/02117, Pfizer inc., Roche, sanofi-aventis. ISRCTN10059974 Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-01-04.