The feasibility of molecular testing on cell blocks created from brush tip washings in the assessment of peripheral lung lesions.

BACKGROUND: With the rapid development of genotype-guided therapies, molecular testing is becoming important in the management of lung cancer. Bronchoscopy is one of the most common investigations performed to diagnose and investigate lung cancer. Given the limited samples often produced by bronchoscopy, this study aims to evaluate the feasibility of performing molecular testing on cell blocks created from bronchoscope cytology brush tip washings (BTW). METHODS: Patients with positive brush cytology for tumour cells had cell blocks created from the BTW. Mutations were detected using amplicon-based massively parallel sequencing of targeted regions of EGFR, KRAS, and BRAF genes. RESULTS: A total of 45 patients were included in this study. Of those, 91% had adequate specimens for molecular analysis and 66% of patients with adenocarcinoma had mutations detected. Bronchial brush tip wash cell blocks were the sole specimen available for molecular testing in 27 (60%) patients. CONCLUSIONS: The findings of this study demonstrate that molecular testing can be performed on cell blocks created from BTW and this technique may allow for an increase in bronchoscope specimens amenable to molecular testing without further increasing morbidity and mortality.

Diagnostic Utility of Bronchial Brush-Tip Washings for the Immunohistochemical Assessment of Peripheral Lung Lesions.

OBJECTIVES: Immunohistochemistry (IHC) is an important component of lung cancer diagnosis and management, although performance can be limited due to tissue availability. We describe a novel technique for processing brush-tip washings (BTW) and evaluate the feasibility of IHC testing on these samples. STUDY DESIGN: All patients who had cell blocks (CB) created from BTW following bronchoscopic investigation of peripheral lung lesions were included. CB were assessed for adequate material before undergoing IHC staining. RESULTS: 75 patients were included in the study, with bronchoscopic diagnosis of malignancy achieved in 77%. Sixty-seven samples (89%) had sufficient cells for diagnosis on CB and 56 of these (84%) proved amenable to IHC. CB created from BTW were the sole specimens available for IHC subtyping in 7 patients (9%). CONCLUSIONS: CB are easily created from BTW and are a simple method for increasing the diagnostic utility of bronchoscopic specimens without increasing the risk or duration of bronchoscopy. IHC can be easily performed in a high proportion of cases, increasing the likelihood of accurate sub-typing of tumours following diagnostic bronchoscopy.

Diagnostic utility and accuracy of rapid on-site evaluation of bronchoscopic brushings.

The aim of the study was to determine the accuracy of rapid on-site examinations, performed on transbronchial brushings of peripheral pulmonary lesions, in determining final bronchoscopic diagnosis. In addition to determining if rapid on-site examination impacts procedural outcomes. A prospective cohort study of consecutive patients with peripheral pulmonary lesions, which had been located by radial endobronchial ultrasound, was undertaken. Bronchoscopy was terminated if rapid on-site examination demonstrated diagnostic malignant material. Non-diagnostic rapid on-site examination resulted in further bronchoscopic sampling, including transbronchial lung biopsy and/or sampling from different locations. 128 peripheral pulmonary lesions were located by endobronchial ultrasound in 118 patients. The final bronchoscopic diagnoses included nonsmall cell lung cancer (n=76), carcinoid (n=3), and metastatic malignancy (n=3). Procedure times were significantly shorter for procedures when rapid on-site examinations demonstrated malignancy compared to those where rapid on-site examination was non-diagnostic (19±8 min versus 31±11 min, respectively; p<0.0001). In four procedures, initial negative rapid on-site examination results prompted redirection of sampling from alternate bronchial segments, resulting in positive diagnostic tissue being obtained. Positive and negative predictive value of rapid on-site examination for a malignant bronchoscopic diagnosis was 63 (97%) out of 65, and 43 (68%) out of 63, respectively. Rapid on-site examination of brushing specimens has a very high, positive, predictive value for bronchoscopic diagnosis of cancer and shortens the bronchoscopy procedure times. It has the potential to reduce complications, improve cost-effectiveness, and may improve diagnostic performance via live feedback.