Circulating tumor cells in operable breast cancer: a pilot study.

Abstract

Abstract Abstract #5028 Background. Circulating tumor cells (CTCs) in the peripheral blood are an ideal source for the detection of disseminated tumor cells because of an easy sampling procedure. Their prognostic significance has been demonstrated in metastatic breast cancer, while little data exist in operable patients. Aims of this study are the evaluation of the prevalence and kinetics of CTCs before and after surgical treatment and the possible correlation between CTCs and clinico-pathological characteristics and biological features. Methods. We analyzed 30 ml of peripheral blood from 60 T1-T3, any N, M0 breast cancer pts, before surgery and after 5 days. In case of positivity of one of the perioperative samples, a further sample was taken after 30 days. The presence of CTCs was assessed with the CellSearch System (Veridex, USA). Samples were subjected to immunomagnetic enrichment with an anti-Epcam-antibody: CTCs were defined as nucleated cells expressing cytokeratin 8, 18 and 19 but lacking CD45. A sample was considered positive when 1 or more cells were detected. Results. Data are available for 50 pts. We found ≥1 CTC in 28% of the pts (n=14/50) before surgery, and in 29% of the patients (n= 12/42 ) at 5 days. The median number of CTCs was 1, with a range of 1-3. We found a borderline significant association between the presence of CTCs at baseline and the presence of vascular invasion (p=0.09). The presence of CTCs at baseline did not correlate with tumor size (p=0.66), grading (p=0.88), presence of estrogens receptor (p=0.30), presence of progesteron receptor (p=0.30), HER2/neu status of the tumor (p=1.0), or with the presence of lymph node metastases (p=0.71). In 42 pts we have the data of CTCs determined at baseline and at day 5: 27 patients showed concordant results (23 negative and 4 positive). Among the 15 patients with different results, 8 were negative at baseline and positive at day 5: 6 out of the 8 patients had positive nodes. At day 30 we analyzed samples from 18 subjects: persistence of at least 1 CTC was found in 18 % of patients (n=5). Conclusions. The results of this explorative study are very preliminary and a larger number of patients and a long-term follow-up will be required. However, it is of interest the borderline correlation between presence of CTCs at baseline and vascular invasion, and between appearance of CTCs and nodal involvement in postoperative samples. The study is ongoing and the patients will be followed during and after adjuvant treatment to explore the prognostic significance of persistency of CTCs. Complete data will be presented. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5028.