January 2017
Results: We compared performance of the assay between two laboratories, finding a high rate of concordance and reproducibility. Using DNA quantities typical of those found in up to 4ml of plasma from cancer patients, our assay provides high sensitivity for variants that are present at allele fraction 0.25% or higher in plasma, and retains substantial sensitivity at allele fractions as low as 0.1%. Standard dilution curves of well-characterized reference samples show that the accuracy of the eTAm-Seq® assay is predominantly limited by stochastic sampling. Analysis of plasma samples from control individuals demonstrates a low false positive rate. Additional data with associated clinical data will be presented at the meeting. Conclusion: Our data demonstrates eTAm-SeqTM assy’s robustness and performance in two labs, supporting its use as a basis for clinical applications globally, allowing a high degree of standardization and comparability for molecular profiling of tumors using liquid biopsy. Keywords: ctDNA, standardized, Concordance, eTAm-Seq
P2.03b-094 Prognostic Value of Serum Carcinoembryonic Antigen during Conventional Chemotherapy in Advanced (Non-)Small Cell Lung Cancer Topic: Biomarkers C. De Jong,1 I. Gordijn,2 J.C. Kelder,3 B. Naaijkens,4 V.H.M. Deneer,1 G.J.M. Herder2 1Clinical Pharmacy, St Antonius Hospital, Nieuwegein/Netherlands, 2 Pulmonology, St Antonius Hospital, Nieuwegein/ Netherlands, 3Cardiology, St Antonius Hospital, Nieuwegein/Netherlands, 4Clinical Chemistry, St Antonius Hospital, Nieuwegein/Netherlands Background: Carcinoembryonic antigen (CEA) is used as a biomarker in colon carcinoma, however in patients with (non-)small cell lung cancer ((N)SCLC) increased serum CEA levels are commonly found. Since decline of high CEA levels in colon carcinoma is predictive for objective response, it is hypothesized that (N)SCLC is also associated with increased CEA concentrations and decreases in CEA levels have prognostic value for therapy response. Methods: In this retrospective observational study, changes in CEA levels during first-line conventional chemotherapy were studied in 194 patients with advanced (N)SCLC. CEA data prior to treatment (baseline),
Abstracts
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on week 3, 6 and 12 were correlated with radiologic objective response, defined as partial or complete response according to RECIST 1.1, overall survival (OS) and presence or occurrence of brain metastases. Results: In total, 122 patients (62.9%) receiving standard chemotherapy between 2012-2016 had elevated baseline CEA levels (>5 ng/mL) with overall radiologic response on week 12 of 27.0% (objective response patients without elevated baseline CEA 15.3%). Within these patients, statistically significant correlations were observed between CEA response (20% decline over baseline level) on week 6 and radiologic objective response on week 12 (OR¼4.3, CI¼1.8-11.1, p<0.001), resulting in a positive and negative predictive value of CEA levels of 65.9% and 69.5% respectively. When adjusted for tumor histology, significant differences in objective response were found in week 12 (NSCLC 15.2% vs SCLC 41.0%, p¼0.001) and in patients with elevated baseline CEA (NSCLC 21.7% vs SCLC 43.3%, p¼0.032). Statistically significant associations were found between CEA responses on week 6 and objective response on week 6 (OR¼4.3, CI¼1.8-11.1, p<0.001, adjusted OR¼3.9) and CEA responses on week 3 and objective response on week 6 (OR¼3.3, CI¼1.3-8.5, p¼0.007, adjusted OR¼2.6). Median survival was 567 days, without significant differences according to CEA levels at diagnosis. No statistically significant associations were found between CEA responses on week 3, 6 and 12 and OS. High CEA concentrations at baseline were not associated with brain metastases at diagnosis or diagnosed within 3 months, even when adjusted for tumor histology. Conclusion: This is one of the first studies in advanced lung cancer which describes that CEA levels appear to be closely associated with objective response. These results show that CEA could be a predictive marker for chemotherapy efficacy in patients with advanced (N) SCLC. Further research to reveal whether CEA decline also predicts response in (N)SCLC patients undergoing novel targeted therapies or immunotherapy is ongoing. Keywords: CEA, carcinoembryonic antigen, NSCLC, SCLC
P2.03b-095 Retrospective Analysis of Correlation between ACEIs/ARBs and Clinical Outcome in Lung Cancer Patients with Bevacizumab-Based Chemotherapy Topic: Biomarkers Sachi Okawa,1 Masanori Fujii,1 Naoyuki Sone,2 Rie Tohnai,1 Ryuichiro Tanaka,1 Yukiko Era,1 Yuji Yokoyama,1 Yusuke Ueda,1 Keisuke Sugimono,1