A Comparison of Cytology and Fluorescence In Situ Hybridization for the Detection of Malignant Bronchial Brushing and Washing Specimens
J Zhai. Cedars-Sinai Medical Center, Los Angeles, CA
Background: The routine bronchial brushing and washing cytology is an important diagnostic tool in the evaluation of patients with suspected lung cancer. Fluorescence in situ hybridization (FISH) is a valuable tool to detect chromosomal abnormalities. FISH has been shown to yield superior sensitivity over routine cytology for the detection of urothelial carcinoma. The LAVysion FISH probes (Abbott Laboratories) are developed for the detection of lung cancer, and contain locus-specific probes to 5p15, 7p12 (EGFR), 8q24 (c-Myc), and a centromeric probes to chromosome 6. The purpose of this prospective study is to evaluate the performance of LAVysion FISH assay over routine cytology for the detection of malignant bronchial brushing and washing specimens.
Design: Forty six consecutive patients who underwent bronchoscopic examination in a period of 6 months were included in the study if bronchial brushing and / or washing specimens were accompanied by concurrent endobronchial biopsy and / or transbronchial fine needle aspirations (FNA), which were used as gold standard. The smears for routine cytology were prepared first using Thin Prep technology and direct smear. The smears for FISH were made from the residue using cytospin preparation. The FISH analysis utilized the commercially available LAVysion probes. The FISH was reported positive if > 6 cells with gains of two or more chromosomes in the same cell, or > 10 cells with all four chromosome copy numbers at 4N. The indeterminate cytology results were considered as negative for statistical analysis.
Results: Twenty eight of the 46 patients were diagnosed of malignancy (22 non small cell carcinoma, 5 small cell carcinoma and 1 granular cell tumor) based on biopsy and / or FNA. For bronchial brushing specimens, the sensitivity of routine cytology and FISH for the detection of malignancy was 17% (3/18) and 33% (6/18) respectively (p=0.08); the specificity of routine cytology and FISH was the same, 78% (7/9). For bronchial washing specimens, the sensitivity of routine cytology and FISH for the detection of malignancy was 8% (2/25) and 28% (7/25) respectively (p=0.025); the specificity of routine cytology and FISH was the same, 94% (15/16).
Conclusions: Our data shows that bronchial cytology appears to have a very low sensitivity for the detection of malignancy and FISH analysis does not appear to improve it to a desirable level. A larger study is necessary to further evaluate the role of FISH analysis in the detection of malignancy on bronchial cytology specimens.
Monday, March 9, 2009 2:15 PM
Platform Session: Section F, Monday Afternoon