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MINI 26 - Circulating Tumor Markers (ID 148)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
MINI26.06 - Cytological Criteria Based in the Characterization of CTCs for Assessment the Response to Erlotinib (ID 2974)
16:45 - 18:15 | Author(s): J. Valdivia
During the past decade, circulating tumor cells (CTCs) have been accepted as new prognostic and predictive factors for some type of cancers. In non small lung cancer cells (NSCLC) their detection and characterization is especially important to identify treatment resistances that some patients develop. Here, we report the value of characterization of CTCs and established cytological criteria to assess a good response for EGFR- tyrosine-Kinase inhibitors
From Feb 2012 to October 2014, 39 patients (median age 63 years) with metastatic lung cancer were included in this study. NSCL (26 Adenocarcinomas and 13 Squamous cell carcinoma) EGFR wild-type patients were being treated with second or higher lines therapies with erlotinib. 10 ml of blood were collected from each patient into a CellSave TM Preservatives Tubes (Veridex, LLC, Johnson & Johnson Company) blood collection tube, maintained at room temperature and processed within a maximum of 72 hr after collection according to the protocol established by our group .For CTCs enrichment from PBMCs we used “Carcinoma Cell Enrichment and Detection kit: MACS technology (Miltenyi Biotechnology), using magnetic beads labeled with a multi-CK-specific. After isolation of CTCs, samples containing CTCs CK+ were stained for EGFR in double immunofluorescence (IF) experiments, following our standard protocol.The assessment of treatment was evaluated by histological criteria (CyCaR: Cytological Criteria of assessment Response).This way, as favorable response was defined when the number of CTCS was reduced more than 50% at 6 or 12 weeks of starting erlotinib treatment
Before treatment 18/39 patients (46%) were identified as positive for CTC[CK+ ]with an average number of 3.5 cell (range 1-11); 9 of which were presented persistence of CTCs after treatment. 7/ 18 patients positive for the presence of CTC[CK + ]were positive to presence EGFR marker (CTC[CK+ /EGFR +).]. More important was, that we found A positive correlation between CTCs and survival: patients with CTC(CK+ /EGFR-) presented a shorter OS (34 vs 53 weeks) and PFS (13 vs 17 weeks) compared with those patients with CTC(CK+ /EGFR +) which responded favorably to erlotinib. Patients without cytological response criteria had a worse survival OS (28 vs 53 weeks, p=0.057) and PFS (11,5 vs 21,3 weeks, p=0.06).
Our study suggests that the characterization of CTC based in the EGFR expression might be useful as a marker for the therapeutic selection and monitoring of lung cancer patients sensitive to treatment with inhibitors of tyrosin-kinase.
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