Suitability of transbronchial biopsies using ultrathin bronchoscope (UTB) and 1.2 mm forceps for genotyping of peripheral pulmonary lesions (PPL)

<bold>Background:</bold> UTB has shown promise in enhancing diagnostic yield by improving visualization of small caliber airways. However, there is a lack of studies investigating the utility of UTB with TBB using 1.2 mm biopsy forceps for genotyping peripheral lung cancer lesions. <bold>Methods:</bold> This prospective cohort study focuses on patients referred for biopsy of PPL. UTB (3 mm outer diameter at tip and 1.7 mm working channel) was routinely employed. Radial EBUS and 2D fluoroscopy were utilized when lesions weren’t visualized endoscopically. Biopsy samples were obtained using 1.2 mm forceps. Molecular analyses, including next-generation sequencing (NGS) and immunohistochemistry (IHC) for PD-L1 expression, were performed on biopsy material post-diagnosis. <bold>Results:</bold> From July 3, 2023, to February 3, 2024, 23 patients with PPL were studied. The median longest diameter in the axial plane was 31 mm, ranging from 15 mm to 55 mm. The diagnostic yield was exceptionally high at 91.3%, and no complications were reported. <bold>Conclusions:</bold> The use UTB with 1.2 mm biopsy forceps in transbronchial biopsies proves to be a reliable tool for diagnosing PPL. The obtained diagnostic material consistently proved adequate for both PD-L1 expression and NGS analyses. These findings suggest the potential clinical utility of 1.2 mm forceps in improving the accuracy of genotyping peripheral lung lesions, contributing valuable insights for future diagnostic approaches. <table-wrap><object-id>erj;64/suppl_68/PA1627/TB1</object-id><object-id>T1</object-id><object-id>TB1</object-id><table><colgroup><col></col><col></col><col></col><col></col><col></col></colgroup><tbody><tr><td>Diagnosis</td><td>N.</td><td>diagnosis obtained by TBB (UTB with 1.2 mm forceps)</td><td>PDL-1</td><td>NGS</td></tr><tr><td>adenocarcinoma</td><td>12</td><td>11</td><td>11</td><td>11</td></tr><tr><td>squamous cell</td><td>3</td><td>3</td><td>3</td><td></td></tr><tr><td>small cell</td><td>3</td><td>3</td><td></td><td></td></tr><tr><td>carcinoma NOS</td><td>3</td><td>3</td><td>3</td><td>3</td></tr><tr><td>linfoma</td><td>1</td><td></td><td></td><td></td></tr><tr><td>Op</td><td>1</td><td>1</td><td></td><td></td></tr></tbody></table></table-wrap>