Value of cytopathology in endobronchial ultrasound-guided transbronchial needle aspiration

Abstract

To evaluate the role of cytopathology in endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for lung tumor diagnosis and staging. Two-hundred consecutive cases of lung tumor with EBUS-TBNA performed during the period from April, 2009 to September, 2010 in Shanghai Cancer Hospital were retrospectively reviewed. The cytologic diagnoses were categorized as non-diagnostic, negative, suspicious and malignant. When available, cell block preparation and immunohistochemistry were performed. On the 22 positive cases diagnosed by on-site evaluation, epidermal growth factor receptor (EGFR) mutation study was carried out. In the 200 cases of cytology specimens, 122 cases (69.3%) were diagnosed as malignant, 42 cases (23.9%) as benign and 12 cases (6.8%) as suspicious for malignancy. The non-diagnostic rate was 12.0% (24/200). Amongst the 200 cases studied, 140 cases (70.0%) had histologic correlation available (via core biopsy, mediastinoscopic biopsy or surgical excision). The sensitivity and specificity of EBUS-TBNA cytologic diagnoses were 94.4% and 100%, when using histopathologic findings and clinical follow-up data as gold standard. The cell block preparation and immunohistochemistry were useful in subtyping and diagnosis of extrathoracic malignancy. EGFR mutations were detected in 8 cytology samples (36.4%). EBUS-TBNA is a sensitive and specific tool for diagnosis and staging of lung cancer. The cytology samples can be used for further ancillary investigations including cell block preparation, immunohistochemistry and molecular studies.