Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) can be used in routine practice to subtype non–small cell lung cancer (NSCLC), according to a study in the June 15 American Journal of Respiratory and Critical Care Medicine.
Neal Navani, MA, MSc, PhD, of University College London Hospital, and colleagues investigated EBUS-TBNA’s ability to provide cytology specimens that are suitable for phenotyping and genotyping NSCLC. EBUS-TBNA uses a 21- or 22-gauge needle to sample mediastinal and hilar lymphadenopathy and is commonly used in patients with suspected NSCLC after CT scan. However, EBUS-TBNA samples are smaller than those obtained by biopsy via mediastinoscopy, and it is unclear whether they are sufficient for subtyping and genotyping of NSCLC to guide treatment.
The researchers analyzed EBUS-TBNA cytological diagnoses of 774 patients with known or suspected lung cancer from five centers in the UK. Local pathologists interpreted the EBUS-TBNA specimens obtained from these patients, and DNA sequencing techniques were used to detect epidermal growth factor receptor (EGFR) mutations in the specimens. Patients were followed for at least six months, and their EBUS- TBNA results were classified as true-positive, true-negative, or false-negative according to the final diagnosis of malignancy. The primary endpoint was the proportion of patients with NSCLC in whom EBUS-TBNA was able to subtype the cancer. The coprimary endpoint was the proportion of samples suitable for EGFR testing.
The EBUS-TBNA specimens allowed for subtyping in 77% of patients with NSCLC. Although the other 23% of NSCLC patients received the diagnosis of NSCLC not otherwise specified (NSCLC-NOS), this proportion is consistent with data from alternative biopsy techniques, the researchers said. EBUS-TBNA had a sensitivity of 88%, a negative predictive value of 72%, and a diagnostic accuracy of 91% in patients with NSCLC. Patients who underwent immunochemistry had a significantly reduced rate of NSCLC-NOS (adjusted odds ratio, 0.50).
Of the 119 (27%) patients for whom EGFR mutation analysis was requested, the analysis was possible in 107 (90%). The analysis identified seven patients with EGFR mutations.
One patient’s EBUS-TBNA procedure resulted in death, which was attributed to the EBUS scope’s carriage of organisms from the pharynx to the lungs. There were no other complications associated with the procedure.
“This large, multicenter, pragmatic study demonstrates that cytology samples obtained from EBUS-TBNA in routine practice are suitable for subtyping of NSCLC and EGFR mutation analysis and that the use of immunohistochemistry reduces the rate of NSCLC-NOS,” the investigators concluded.
Navani N, Brown JM, Nankivell M. Suitability of endobronchial ultrasound-guided transbronchial needle aspiration specimens for subtyping and genotyping of non-small cell lung cancer: a multicenter study of 774 patients. Am J Respir Crit Care Med. 2012;185(12):1316-1322.