Endobronchial ultrasound in the management of nonsmall cell lung cancer

Abstract

Flexible bronchoscopy plays a major role in the diagnosis and staging of lung cancer. One of the most important advances in this field is the development of endobronchial ultrasound (EBUS), which has extended the view of the bronchoscopist. These techniques are safe and allow assessment of the depth of tumour invasion in the central airways, detection of peripheral tumours before sampling, localisation of the central tumour in the lung parenchyma close to the central airways for real-time guided sampling, and staging of lymph nodes within the mediastinum. Progress in handling and analyses of the small samples obtained during EBUS procedures also allow modern pathological and molecular studies to be performed. This article reviews the data currently available in the field of convex and radial probe EBUS for the diagnosis and staging of nonsmall cell lung cancer and highlights the strengths but also the weaknesses of these new techniques.

Keywords: Endobronchial ultrasound; lung cancer; mediastinal lymphadenopathy; peripheral lung cancer; staging; transbronchial needle aspiration.

Figure 1.

A convex ultrasound transducer is located at the tip of a dedicated bronchoscope for peribronchial linear scanning (bottom). A radial ultrasound transducer miniprobe is introduced through the biopsy channel of a standard bronchoscope for endobronchial scanning (top).

Figure 2.

The radial endobronchial ultrasound miniprobe can visualise a) normal lung parenchyma (“snow-storm” pattern) or b) solid peripheral pulmonary lesion.

Figure 3.

a) White light and b) autofluorescence bronchoscopy of an early stage radio-occult squamous cell carcinoma, which has been proven invasive by radial endobronchial ultrasound miniprobe with filled balloon sheath (c and d). The ultrasound image (d) illustrates interruption of white “cartilage” line, as indicated by the arrows. RB: right bronchus.

Figure 4.

a) White light bronchoscopy of an early stage radio-occult squamous cell carcinoma, which has been proven micro-invasive by radial endobronchial ultrasound miniprobe with filled balloon sheath (b), and on histopathology (c). The arrows in b) indicate the intact white “cartilage” line on the ultrasound image.

Figure 5.

Schematic representation of the mediastinum and nodal stations that are accessible to EBUS. Ao: aorta; AP: pulmonary artery; Az: azygos vein; B: brachiocephalic artery; L: left; R: right. For precise borders of the nodal stations see [36].