Clinical value of CTC in predicting the efficacy of treatment in breast cancer.

Abstract

e12104 Background: Circulating tumor cells (CTCs) have proven to be underlying surrogate markers for several cancers. We aimed to investigate the diagnostic, predictive, and prognostic value of tCTCs using a four-CTC marker (CK19, surviving, Her2 and MUC1) real-time quantitative PCR (RT-PCR) assay in patients with breast cancer. Methods: In a previous study, we established a multimarker RT-PCR platform to detect and quantify CTC in colorectal cancer. By choosing four mRNA markers (CK-19/surviving/Her2/Muc1), we quantified CTC in the peripheral blood of 90 early operable breast cancer patients, 40 patients who had undergone surgery and received 6 cycles of follow-up of neoadjuvant chemotherapy, and 30 healthy volunteers. For early operable breast cancer patients, the CTC status at preoperative and postoperative time points was monitored. For the other 40 patients undergoing systemic adjuvant chemotherapy, the CTC status at six or more different time points was monitored. Results: CTCs were detected in 81% (73/90) of patients with early operable breast cancer. After surgery, 67.1% (49/73) of the patients switched to negative status. 36 out of 40 (90%) patients who received systemic adjuvant chemotherapy were CTC-positive. During follow-up, 31 out of 36 (86%,) patients became CTC-negative after 4 chemotherapy cycles. Among these 36 patients, four patients had relapsed within one year, and one had died. Three out of four relapsed patients, including the deceased one, switched into high CTC-positive status before diagnosed recurrence. Conclusions: The decrease of the levels of these CTC mRNA markers after surgery indicates that these CTC markers could be used as an indirect evaluation of tumor burden. The level of CTC mRNA markers could also help to evaluate therapeutic efficacy and disease progression.