Transbronchial Techniques for Lung Cancer Treatment: Where Are We Now?

Abstract

The demand for parenchyma-sparing local therapies for lung cancer is rising owing to an increasing incidence of multifocal lung cancers and patients who are unfit for surgery. With the latest evidence of the efficacy of lung cancer screening, more premalignant or early-stage lung cancers are being discovered and the paradigm has shifted from treatment to prevention. Transbronchial therapy is an important armamentarium in the local treatment of lung cancers, with microwave ablation being the most promising based on early to midterm results. Adjuncts to improve transbronchial ablation efficiency and accuracy include mobile C-arm platforms, software to correct for the CT-to-body divergence, metal-containing nanoparticles, and robotic bronchoscopy. Other forms of energy including steam vapor therapy and pulse electric field are under intensive investigation.

Keywords: local treatment; lung cancer; lung cancer screening; robotic bronchoscopy; transbronchial ablation techniques.

Figure 1

(A,B) Right lower lobe lung lesion before (A) and after (B) the first transbronchial microwave ablation in two axes on a cone beam CT scan. The lesion is marked by orange tracings while the green and red ovals represent the predicted ablation zone. In (B), ablative changes represented by ground glass opacities are seen surrounding the ablation catheter as predicted; however, the margin was only 2 mm. Therefore, repositioning of the ablation catheter and re-ablation were performed as shown in (C), and the final cone beam computer tomography (CBCT) shows a satisfactory margin of 6.7 mm.

Figure 2

Images during ENB navigation using the Illumisite^TM platform. (A) Tip of the locatable guide pointing directly at the lesion (represented by the green ball) after peripheral navigation. In (B), the locatable guide was removed, but there were positional sensors embedded in the extended working channel which is shown pointing slightly off-center at the lesion. In (C), the crosshair is shown, pointing slightly off-center at the lesion which would require further manipulation to ensure target view, while the tip of the catheter is shown to be 2 cm from the target lesion.

Figure 3

Picture of the operating room setup during Cios Spin^® mobile C-arm image acquisition.

Figure 4

An example of robotic-assisted bronchoscopy by Auris Monarch^TM with cone beam CT in a hybrid operating room. This improves the accuracy of navigation, biopsy, or local treatment.

Figure 5

During robotic-assisted bronchoscopy by Auris Monarch^TM, multiple panels can be visualized simultaneously: the left-hand panel shows the real-time bronchoscopic view, the middle ones show the bull’s eye view with the centered crosshair and the lesion (in yellow); the right-hand panels show the preoperative CT scan images in three perpendicular axes.