248P - Monitoring Circulating Tumor Cells (Ctc) in Lung Cancer: Preliminary Results

Abstract

ABSTRACT Aim: The value of CTC is unclear in patients (p) with lung cancer, in particular in those with locally advanced disease. Methods: Basally peripheral blood samples are been collected for prospective CTC analysis in all lung cancer p, as well as, after finishing chemotherapy and radiotherapy in stage III and SCLC. CTC analysis is performed using Cellsearch (Veridex). Results: So far now, 238 p with newly diagnosed lung cancer (200 NSCLC and 38 SCLC) have been enrolled (January 2012 - April 2014). CTC were positives (CTC ≥1) in 21.5% of NSCLC p (43/200) and 65.8% of SCLC p (25/38). The number of CTC varied between 1-136 in NSCLC and 7 - 6.197 in SCLC. 42.1% the SCLC p had1-100 CTCs and 23.7% the patients had >100 CTCs. Regarding NSCLC p, with a median follow up period of 254 days: 116 p (58.5%) had progression disease and 74 p (37%) had death. The MST for 157 p NSCLC with CTC = 0 was significantly longer (not achieved) compared to 43 p with a CTC ≥1 (17 months; 95% CI, 7.57-26.42) p = 0.002. Similarly, the TTP for the group CTC = 0 was significantly longer (11 months) compared to CTC ≥ 1 (6 months) p: 0.0002. Basaline CTC = 0 in NSCLC showed better results to treatment (parcial or complete vus progression or stable response) with HR 0.44; 95% CI(0.2-0.9), p:0.043 comparing to CTCs ≥ 1. Regarding FU, only 1 p had +CTC at the end of treatment vs 3 more p at the moment of progresion. However, no statistically significant difference was found in terms of MST and TTP in the group of stage III p comparing p with CTC ≥ 1 vs CTC = 0. SCLC p with baseline CTCs ≥1 had a trends for unfavorable survival (HR 1.34, 95% CI 0.59-3.05, p = 0.48). The MST was 10 months compared to the group of 13 p with a CTC =0 (7 months), p = 0.45. The group with a CTC > 100 (9 p) had a unfavorable overall survival with HR 6.69 (95% CI, 1.77-26.24, p = 0.06). CTCs ≥1 following treatment (5/18p) in SCLC had significantly higher risk of death than the group (13/18p) with CTC =0 (HR 9.78 p:0.049) Conclusions: The results of a multivariate analysis showed that the baseline CTC count was an independent prognostic factor for survival time.The role of CTC in stage III NSCLC is still unclear due to the low incidence of CTCs at diagnosis (14.5%), at the end of first treatment or at the time of progression. In contrast, CTCs were highly detectable in SCLC patients from our study, so that their value as predictive factor will depend on the dynamic changes to be collected. Disclosure: All authors have declared no conflicts of interest.