Concordance of Cytological Specimens with Histological Tissue for Detection of Epidermal Growth Factor Receptor Mutation in Non-Small Cell Lung Cancer: A Systematic Review

Abstract

<b><i>Introduction:</i></b> There is increasing need for more testing in non-small cell lung cancer given the introduction of newer targeted therapies. Cytological specimens including conventional smears (CS), cell blocks (CB), and liquid-based cytology (LBC) are an alternative to histologic tissue (HT) specimens in detecting <i>EGFR</i> mutations, but the concordance of these 2 specimens is yet to be determined. The aim of the present systematic review is to determine the concordance rates between different cytologic specimens with HT in detecting <i>EGFR</i> mutations. <b><i>Methods:</i></b> PubMed, Cochrane Library, and Google Scholar were utilized in the primary search, along with reference lists of electronically retrieved full-text articles. Concordance rates were pooled together if 2 or more studies reporting the same type of cytologic specimen were available. <b><i>Results:</i></b> Overall, 15 studies were included in this review, with 13 studies included in the pooled analysis. There was an overall concordance rate of 92.8% in 593 paired cytologic and HT specimens, with LBC having the highest concordance rate of 96.0%, followed by CS and CB, each with a concordance rate of 95.8%, although the concordance rate of CS and/or CB was lower at 90.6% with a larger pool of studies. LBC was found to have a significantly higher concordance rate than CS and/or CB. <b><i>Conclusion:</i></b> Cytological specimens have a high concordance rate in detecting <i>EGFR</i> mutations, when compared to HT. LBC has shown superior concordance rates compared to CS and CB. Cytological specimens should be considered as an additional and alternative source of diagnostic material for <i>EGFR</i> testing.