C110-09 Diagnostic Performance of CT-Guided Transthoracic vs. Bronchoscopic Biopsies in Pulmonary Nodules

Rationale Accurate diagnosis of pulmonary nodules is essential for timely management and treatment of lung cancer. Both CT-guided transthoracic needle (TTNB) and transbronchial biopsies (TBB) are widely used, but comparative data on diagnostic performance, concordance between modalities, and escalation rates are limited. This study evaluates the diagnostic yield and complication profile when each modality is performed first in a real-world cohort. Methods Retrospective analysis of adults undergoing both TTNB and TBB of the same pulmonary lesion within six months from 2014-2025. Patients were categorized as TTNB-first or TBB-first based on initial procedure. TBB was further defined as endobronchial ultrasound (EBUS) or electromagnetic navigational bronchoscopy (EMNB). Pathology results were classified as concordant, discordant (benign/nondiagnostic to malignant), upgrade (suspicious to malignant), or downgrade (malignant to benign/nondiagnostic). The primary endpoint was actionable diagnostic change (discordant or upgrade). Secondary measures included concordance, complications, and time between biopsies. Results Among 100 patients (mean age 70; 52% male), 70 were TBB-first and 30 TTNB-first. Discordance was significantly higher for TTB-first (42/70, 60%) than TTNB-first (8/30, 26.7%), p = 0.005 (Table 1). Concordance was higher for TTNB-first (15/30, 50.0%) than TBB-first (24/70, 34.3%). Upgrade rates were 2.9% vs 13.3%, respectively. Downgrade rates were 2.9% vs 10.0%, respectively. The interval between procedures was shorter for TBB-first (median 3 weeks) than TTNB-first (5 weeks), suggesting rapid escalation following nondiagnostic bronchoscopy. Clinically significant complication rates for each biopsy technique were similar, with pneumothorax requiring chest tube placement occurring in 3% of TTNB and 1% of TBB cases. Within the TBB-first cohort, actionable change after second biopsy occurred in 52.6% following initial EBUS and 75.0% following EMNB, indicating possible differences in navigational bronchoscopy diagnostic yield. Conclusions Sequential biopsy analysis revealed that TTNB-first was associated with higher initial concordance and fewer diagnostic upgrades, while TBB-first more frequently required escalation to TTNB for definitive diagnosis. Complication rates were low and similar across modalities. These findings suggest that TTNB may reduce repeat testing in select patients. Prospective studies incorporating lesion characteristics, procedural variables, and cost-effectiveness are warranted. Table 1. Diagnostic Comparisons by Initial Biopsy Modality Comparison of diagnostic outcomes between patients undergoing transbronchial biopsy (TBB) first versus transthoracic needle biopsy (TTNB) first of the same nodule. Pathology results were categorized as concordant (same diagnoses), discordant (different diagnoses), upgrade (less suspicious to more suspicious of malignancy), or downgrade (more suspicious to less suspicious of malignancy). This abstract is funded by: None