Differences in pathological diagnoses between bronchoscopic tissue and resected specimens of non-small cell lung cancer: A retrospective single center study

Abstract Background Immune checkpoint inhibitor (ICI) combination chemotherapy has been used as preoperative and postoperative treatment for resectable non-small cell lung cancer. Programmed cell death protein-1 (PD-L1) is a biomarker that predicts the therapeutic effect of ICIs. In lung cancer, it is evaluated using the Tumor Proportion Score. Tumors are heterogeneous, and if the amount of collected tissue is small, the location of the tissue may affect the diagnosis. We evaluated the revision rate of the resected specimens and considered its impact on PD-L1 measurement. Methods Over 5 years, 237 cases of non-small cell lung cancer underwent surgery. Of these, 126 cases underwent preoperative bronchoscopy. Bronchoscopy included forceps biopsy, brushing, and bronchoalveolar lavage. Endoscopic ultrasound was used for peripheral lesions. Cases in which cancer was diagnosed from bronchoscopic specimens were considered to have a definitive diagnosis. Simultaneous multiple small cell and non-small cell lung cancer were identified. Cases of small cell lung cancer were excluded from analyses. Results Bronchoscopy diagnosed cancer in 45.2% of cases. The revision rate of pathological diagnosis in resected specimens was 10.5%. Cases diagnosed as adenosquamous carcinoma, large cell neuroendocrine carcinoma, large cell carcinoma, spindle cell carcinoma, or pleomorphic carcinoma in resected specimens may have been revised from the diagnosis based on preoperative bronchoscopic specimens. In this study, 19.8% of cases were pathological stage 0-IA2 with T factors 2 cm or less, and the diagnostic rate by bronchoscopic examination was low at 16%. PD-L1 testing was measured in 11 cases using bronchoscopic specimens, one of which could not be measured because there was no evaluable tumor. Conclusions In this study, the pathological revision rate was 10.5% when comparing preoperative bronchoscopic specimens with resected specimens, which may have had an impact on PD-L1 evaluation.