Introduction and utility of liquid-based cytology on aspiration biopsy of peripheral nodular lesions of the lung

Molecular Testing in EBUS-TBNA Specimens of Lung Adenocarcinoma: A Study of Concordance Between Cell Block Method and Liquid-Based Cytology in Appraising Sample Cellularity and EGFR Mutations

PURPOSE

Cytological endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) specimens of mediastinal lymph node metastasis are frequently used to perform concomitant diagnosis, staging and genetic testing in non-small-cell lung cancer (NSCLC). The purposes of this single-center retrospective study were to evaluate EBUS-TBNA samples' adequacy for molecular testing of epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK), and to analyze the concordance between the cell block method and liquid-based cytology (LBC) in appraising the sample cellularity and in detecting EGFR mutation.

MATERIALS AND METHODS

We retrospectively examined 82 patients who underwent EBUS-TBNA from October 2012 to September 2015 and received a confirmed diagnosis of lymph node metastasis of lung adenocarcinoma. Each sample was processed using both cell block and LBC to carry out DNA analysis (adequacy criterion: tumor cell percentage > 25%) and EGFR mutation testing.

RESULTS

Fifty-four patients were male, 66 were current or former-smokers, and the median age was 67 years. The median size of sampled lymph nodes was 14.8 mm. Seventy-one and 66 samples were adequate to perform cell block and LBC, respectively. The κ-statistic (0.78) showed an excellent concordance. EGFR mutation was detected in eight patients using cell block and in seven using LBC, with a simple percentage agreement of 87.5%. ALK translocation was found in two patients.

CONCLUSIONS

This study demonstrates the feasibility of EGFR mutation analysis with both cell block and LBC, with an excellent concordance between the two methods. Considering that the majority of advanced NSCLCs are diagnosed on cytology specimens, LBC is feasible and needs to be implemented for ancillary tests (immunocytochemistry, molecular analysis).

Comparison of Conventional Smear and Liquid-based Cytology Preparation in Diagnosis of Lung Cancer by Bronchial Wash and Transbronchial Needle Aspiration

Introduction:

Liquid-based cytology (LBC), initially developed for screening gynecologic specimens, is now being used in nongynecologic aspiration and exfoliative specimens. In this study, the diagnostic yield and utility of thin-prep (TP) was compared with conventional preparations to ascertain its utility in improving the diagnosis of respiratory lesions.

Materials and Methods:

Bronchial washings (BW) and transbronchial needle aspirates (TBNA) (bronchoscopy/endobronchial ultrasound-guided) from 70 consecutive patients of mediastinal masses and endo/peribronchial growths were included. The diagnostic yields of both conventional smears and thin-prep were compared. Immunocytochemistry (ICC) was performed on direct/cytospin smears of TBNA/BW and TP slides when the tumor could not be subtyped by morphology. Histopathologic correlation was done.

Results:

Although well-preserved morphological features and cleaner background in TP allowed accurate diagnosis of malignancies, diagnostic yield was comparable to conventional preparations. Immunocytochemistry was successfully employed on TP smears which helped in accurate subtyping of the tumors. Few shortcomings of TP smears were uneven distribution of cells, thick cell clusters, and inadequate cellularity.

Conclusion:

Liquid-based TP preparation is an effective diagnostic tool for respiratory tract cytology, however, results are comparable to conventional smears.