Sampling Instruments for the Transbronchial Approach to Peripheral Pulmonary Lesions: Which Tool? Are Many Better Than a FEW?

Suitability of transbronchial needle aspiration for genotyping peripheral pulmonary tumors

Background

Transbronchial needle aspiration (TBNA) is a sampling tool that has demonstrated a higher accuracy in the diagnosis of peripheral pulmonary lesions (PPL) compared to other techniques. However, there are no studies investigating the value of TBNA in defining the genotype of peripheral lung cancer.

Objective

To evaluate the accuracy of TBNA in defining the molecular characteristics of peripheral lung cancer.

Methods

Consecutive patients who underwent TBNA for the diagnosis of a PPL at the Pulmonary Unit of the Azienda Ospedali Riuniti of Ancona (Italy) between January 2020 and September 2022 were included in the study. TBNA was performed under fluoroscopic guidance and the additional support of an ultrasound miniprobe, with an ultrathin bronchoscope with a flexible 21G needle. Samples were smeared on glass slides for cytological evaluation and flushed in 10% neutral-buffered formalin for cell-blocks.

Results

154 patients were enrolled:55 were diagnosed with adenocarcinoma and 21 with squamous cell carcinoma. TBNA correctly diagnosed 43/55 (78.2%) patients with adenocarcinoma and 17/21 (81.0%) patients with squamous cell carcinoma, with a sensitivity of 77.5%. Complete genotyping for guiding targeted therapies was obtained in 52 patients (86.6%).

Conclusions

TBNA is a valid tool for the diagnosis of PPL, allowing a correct diagnosis and a complete genotyping of the tumors in a considerable proportion of patients.

Bronchoscopic diagnosis of peripheral lung lesions

PURPOSE OF REVIEW

Over the last decades, in addition to the traditional fluoroscopy, various and innovative guidance systems have been adopted in clinical practice for transbronchial approach to peripheral pulmonary lesions (PPLs). The aim of this article is to summarize the most recent data on available guidance systems and sampling tools, evaluating also advantages and limitations of each technique.

RECENT FINDINGS

Although several studies have been published over the last years, large randomized studies comparing the different techniques are scanty. Fluoroscopy is the traditional and still most widely utilized guidance system. New guidance systems (electromagnetic navigation bronchoscopy, ultrasound miniprobe, cone beam computed tomography) seems to provide a better sensitivity, especially for small lesions not visualized by fluoroscopy. Among the sampling instruments, there is a good evidence that flexible transbronchial needle provides the better diagnostic yield and that sensitivity may increase if more than one sampling instrument is used.

SUMMARY

Even if great progress has been done since the first articles on the transbronchial approach to PPLs, better scientific evidence and more reliable randomized trials are needed to guide interventional pulmonologists in choosing the best technique according to different clinical scenarios and source availability.