Circulating tumor cell analysis in patients with advanced non-small cell lung cancer treated with biweekly gemcitabine and docetaxel.

Abstract

e18085 Background: Circulating tumor cells (CTC) may be useful to predict prognosis in lung cancer patients. The purpose of this study is the detection and quantification of CTC to assess its clinical significance in patients with advanced non-small cell lung cancer (NSCLC) treated with biweekly gemcitabine and docetaxel. Methods: Patients with advance (stage IIIB/IV) NSCLC treated with biweekly gemcitabine and docetaxel in a two parallel phase II trial for patients with performance status 2 and elderly patients were eligible. We used CellSerch System, which consist an immunomagnetic enrichment using anti-EpCAM antibodies and staining for cytokeratin 8, 18, 19, CD45 and DAPI. 7.5 ml of venous blood were collected at the baseline (before treatment) and after 2 cycles of chemotherapy (2 months) to quantify CTC. Results: At baseline, CTC were analyzed in 31 patients (11 pts from PS 2 study and 20 from Elderly study), although CTC quantification was available for both visits for 22 patients. CTC ≥1 was detected in 13 patients (42%). Patients were subdivided in four groups: Group 1 (CTC at baseline = 0; CTC at 2 months =0), Group 2 (CTC at baseline >0; CTC at 2 months =0), Group 3 (CTC at baseline = 0; CTC at 2 months >0) and Group 4 (CTC at baseline > 0; CTC at 2 months >0). 12 patients belong to Group 1 and 10 to Group 2. Characteristics of the patients for both groups are shown in the Table. Time to progression (TTP) was no significantly different for Group 1 (6.1 months) and Group 2 (8.3 months). Median overall survival for group 1 was 8.1 months while it has not been reached for the group 2. Conclusions: CTC measurement may be a useful as a surrogate marker for determining prognosis in advanced NSCLC patients treated with chemotherapy. The number of patients analyzed in this study is small and warrant further studies to drawn solid conclusions. Patients' characteristics Group 1 Group 2 Age (yr) Median 74 74 Range 55-77 56-82 Sex (%) Male 12 (100%) 9 (90%) Female 1 (10%) Histology (%) Adenocarcinoma 4 (33.3) 3 (30) Squamous 3 (30) Large cell 7 (58.3) 3 (30) Others 1 (8.3) 1 (10) Response (%) Partial response 3 (25) 2 (20) Stable disease 7 (58.3) 6 (60) Progressive disease 1 (8.3) 1 (10) No evaluable 1 (8.3) 1 (10) No significant financial relationships to disclose.