Additional 1.1-mm cryobiopsy trial guided by rapid on-site cytologic evaluation of touch imprint cytology result of small forceps biopsy in peripheral pulmonary lesions: a prospective single-center study.

Background: Ultrathin cryobiopsy (CB) using a 1.1-mm cryoprobe has been shown to improve the diagnostic yield of bronchoscopy for peripheral pulmonary lesions (PPLs). However, CB may not be actively adopted in some institutions because of concerns about bleeding and pneumothorax. Each facility needs to develop its own strategies to perform CB selectively and safely. Rapid on-site cytologic evaluation of touch imprint cytology (ROSE-TIC) of small (1.5 mm) forceps biopsy (FB) may help guide the selective application of CB. This study aimed to evaluate the safety and efficacy of adding CB in patients with ROSE-TIC-negative FB. Methods: Patients with PPLs <30 mm were enrolled in this single-center prospective study. First, they underwent bronchoscopic biopsy with a 1.5-mm FB and ROSE-TIC. CB using a 1.1-mm cryoprobe was added only when the ROSE-TIC of the FB was negative. Safety outcomes (especially bleeding) and diagnostic yields were compared solely between ROSE-TIC-positive and ROSE-TIC-negative groups. In addition, the diagnostic yield of FB results, regardless of ROSE-TIC positivity or negativity, was evaluated. The specimen sizes and ROSE-TIC accuracies were also assessed. Results: From November 2023 to March 2025, 50 patients underwent bronchoscopic examinations according to the intended protocol. Grade ≥3 bleeding events did not occur, and Grade 1-2 bleeding was not significantly different between the ROSE-TIC-positive and ROSE-TIC-negative groups (P=0.35). The specific diagnostic yield of the ROSE-TIC-positive group was 87.5%, and that of the ROSE-TIC-negative group was 73.l%. In the ROSE-TIC-negative group, the FB-only results made a specific diagnosis in 34.6% [95% confidence interval (CI): 17.2-55.7%] compared with combined CB in 73.1% (95% CI: 44.3-82.8%). The overall diagnostic yield of specific findings was significantly higher in the combined CB group than that in the FB group (80% vs. 60%; P≤0.01). Additional CB provided diagnostic benefits, particularly for small lesions of ≤20 mm (73.6% vs. 52.6%, P=0.01), and partial solid nodules on computed tomography were more beneficial for pathological findings with additional CB (76% vs. 41%, P=0.04). CB samples were significantly larger than FB samples (median 2.70 vs. 1.35 mm2; P<0.001). ROSE-TIC demonstrated a sensitivity of 79.3% and specificity of 95.2%. Conclusions: The selective addition of a 1.1-mm CB based on ROSE-TIC results of FB is a safe, feasible, and effective strategy for improving the specific diagnostic yield. This approach may be particularly beneficial for small PPLs of ≤20 mm.