Feasibility and utility of transbronchial cryobiopsy in primary lung cancer: Prospective, single arm study

Background: Transbronchial forceps biopsy (FB) is the standard diagnostic tool for primary lung cancer. Recently, we need much amount of tissues for pathological diagnosis, mutational analysis and immunohistochemistry (IHC). The aim of this study was to prospectively evaluate safety, utility for diagnosis of primary lung cancer and biomarker analysis using cryoprobe, that was new transbronchial biopsy tool. Methods: A total of 128 patients with suspected of primary lung cancer were enrolled in this single arm trial and 121 patients were performed both transbronchial normal FB and transbronchial cryobiopsy (TBCB). We evaluated safety especially in bleeding and pneumothorax, diagnostic yield of malignancies, morphological diagnosis, size, tumor concentration of tissue samples and success rate of biomarker analysis. Results: Total diagnostic yield of TBCB was 92% (111/121), in details, 97% (62/64) in central bronchial lesions and 86% (49/57) in peropheral lung lesions. TBCB samples were more useful for morphological classification (86% vs. 79%), and larger size (median size was 15mm2vs. 2mm2, p < 0.001) than FB samples. The ratio of containing malignant cells in each FFPE samples were higher in TBCB (84% (148/177)) than in FB (73% (285/391)). TBCB was more useful for mutational analysis and PD-L1 IHC. Severe bleeding (need to sprinkle hemostatic) was observed each 1 case and grade 3 lung infection (need hospitalization and IV antibiotics) occurred in 4 patients (3%). There was no case of pneumothorax. Conclusions: TBCB is safe technique and useful for diagnosis of primary lung cancer. Furthermore, we could obtain more quantity and better quality of sample for diagnosis and biomarker analysis in comparison with conventional FB. Legal entity responsible for the study: National Cancer Center Hospital. Funding: Japan Agency for Medical Research and development (15ck106111h0002). Disclosure: All authors have declared no conflicts of interest.