CONCORDANCE BETWEEN SERUM AND TISSUE EGFR MUTATIONS IN PATIENTS WITH ADENOCARCINOMA LUNG.

Abstract

Background: EGFR (epidermal growth factor receptor) mutation is indispensable for making therapeutic decisions regarding whether to use EGFR tyrosine kinase inhibitor (TKI) for lung cancer. Because some cases might pose challenges for biopsy, non-invasive detection of EGFR mutation from serum would be beneficial for lung cancer treatment.
Objective: To evaluate the overall concordance between serum and tissue for detecting EGFR mutations in patients with adenocarcinoma lung.
Study Design: Prospective Observational Study.
Participants: The study population consisted of 50 patients; age ranged from 30 to 90 years (median 60 years); 28 (56%) patients were females and 22 (44%) were male.
Materials and Methods: The patients of NSCLC were subjected to clinical evaluation and appropriate sample collection was done ,EGFR mutations (in exons 19, 20, 21) were determined by the Allele Specific PCR (AS-PCR) technique using Q1A amp circulating nucleic acid kit (Qiagen, Germany; catalogue no. 55114). The recorded data was compiled and Sensitivity, Specificity, Likelihood Ratio, PPV and NPV values were obtained to determine the concordance between serum and tissue for detecting mutations in various exons. Chi-square test was employed to determine the association of EGFR mutations with demographic and clinical parameters.
Results: In our study, 48% patients were either current or reformed smokers, 41% of the patients had smoking index of more than 500. Lifetime non-smokers were 52%.On clinical evaluation 56% patients had metastatic disease. Upon analysis total number of mutations detected in serum were 44% and that in tissue were 66% and concordance was detected in around 76% of cases.
Conclusion: Detection of EGFR mutations in the Serum of NSCLC (adenocarcinoma) patients provides good concordance and high specificity as compared to mutations detected in Tissue specimen.
Implication: Serum, being noninvasive, appears to be a promising surrogate to tissue for detection of EGFR mutations.