Effect of adjuvant treatment on the circulating CK-19 mRNA-positive tumor cells in patients with early stage breast cancer

Abstract

20012 Background: To evaluate the effect of adjuvant treatment on the peripheral blood CK-19 mRNA circulating tumor cells (CTCs) in patients with early-stage breast cancer. Methods: CTCs were detected by real-time RT-PCR assay, in 119 patients with estrogen or/and progesterone receptors-positive tumors at the following time points: before the initiation and after the completion of adjuvant chemotherapy and every 3 or 6 months during the period of adjuvant tamoxifen administration. Results: Adjuvant chemotherapy failed to “eliminate” the CTCs in 17 (47%) out of 36 patients with detectable cells in pre-chemotherapy samples; in addition, adjuvant tamoxifen failed to “eliminate” the CTCs in 8 (36.4%) of 22 patients displaying detectable cells in post-chemotherapy samples. The incidence of clinical relapse was significantly (p = 0.017) higher for patients with post-chemotherapy detectable CTCs as well as for patients with persistently detectable CTCs throughout the follow-up period compared with those who did not (65.3% vs 7.3%, respectively; p < 0.001). In multivariate analysis, post-chemotherapy detection of CTCs and their persistence throughout the follow-up period were significantly associated (p = 0.001 and 0.003, respectively) with early relapse. Conclusions: The detection of CK-19 mRNA+ CTCs after adjuvant chemotherapy and during tamoxifen administration is an independent prognostic factor associated with unfavorable outcome. No significant financial relationships to disclose.