A Comparison of Cytology and Fluorescence in Situ Hybridization for the Detection of Lung Cancer in Bronchoscopic Specimens

Study objectivesTo determine the relative sensitivity and specificity of cytology and fluorescence in situ hybridization (FISH) for the detection of lung cancer in bronchoscopically obtained specimens.DesignCytology and FISH were performed on brushing and washing specimens obtained from patients undergoing bronchoscopy for suspected lung cancer. FISH utilized the LAVysion probe set (Abbott Molecular; Des Plaines, IL), which contains locus-specific probes to 5p15, 7p12 (EGFR), 8q24 (C-MYC), and a centromeric probe to chromosome 6.SettingSingle-center, academic, tertiary medical center.ParticipantsOne hundred thirty-seven patients referred for bronchoscopy for suspicion of lung cancer.InterventionsCytology and FISH were performed on bronchoscopic brushings and washings.Measurements and resultsOne hundred thirty-seven patients undergoing bronchoscopy had pathology, FISH, and cytology results. FISH and cytology were performed on 123 washing and 78 brushing specimens. Sensitivities of FISH and cytology were 71% and 51% (p = 0.007), respectively, for brushing specimens, and 49% and 44% (p = 0.541) for washing specimens. When FISH and cytology results were combined, sensitivities were 75% and 61%, respectively, for brushing and washing specimens, which was significantly better (p < 0.001) than cytology alone. Specificities of FISH and cytology for patients with negative findings at the time of initial bronchoscopy were 83% and 100% (p = 0.125), respectively, for brushing specimens, and 95% and 100% (p = 0.500) for washing specimens.ConclusionsThese findings show that FISH is significantly more sensitive than conventional cytology for detecting lung cancer in bronchial brushing specimens; when combined with cytology, FISH can improve the diagnostic sensitivity of detecting malignancy in bronchial brushing and washing specimens.