Shape-Sensing Robotic-Assisted Bronchoscopy in the Diagnosis of Pulmonary Parenchymal Lesions

Abstract

Background: The landscape of guided bronchoscopy for the sampling of pulmonary parenchymal lesions is evolving rapidly. Shape-sensing robotic-assisted bronchoscopy (ssRAB) recently was introduced as means to allow successful sampling of traditionally challenging lesions.

Research question: What are the feasibility, diagnostic yield, determinants of diagnostic sampling, and safety of ssRAB in patients with pulmonary lesions?

Study design and methods: Data from 131 consecutive ssRAB procedures performed at a US-based cancer center between October 2019 and July 2020 were captured prospectively and analyzed retrospectively. Definitions of diagnostic procedures were based on prior standards. Associations of procedure- and lesion-related factors with diagnostic yield were examined by univariate and multivariate generalized linear mixed models.

Results: A total of 159 pulmonary lesions were targeted during 131 ssRAB procedures. The median lesion size was 1.8 cm, 59.1% of lesions were in the upper lobe, and 66.7% of lesions were beyond a sixth-generation airway. The navigational success rate was 98.7%. The overall diagnostic yield was 81.7%. Lesion size of ≥ 1.8 cm and central location were associated significantly with a diagnostic procedure in the univariate analysis. In the multivariate model, lesions of ≥ 1.8 cm were more likely to be diagnostic compared with lesions < 1.8 cm, after adjusting for lung centrality (OR, 12.22; 95% CI, 1.66-90.10). The sensitivity and negative predictive value of ssRAB for primary thoracic malignancies were 79.8% and 72.4%, respectively. The overall complication rate was 3.0%, and the pneumothorax rate was 1.5%.

Interpretation: This study was the first to provide comprehensive evidence regarding the usefulness and diagnostic yield of ssRAB in the sampling of pulmonary parenchymal lesions. ssRAB may represent a significant advancement in the ability to access and sample successfully traditionally challenging pulmonary lesions via the bronchoscopic approach, while maintaining a superb safety profile. Lesion size seems to remain the major predictor of a diagnostic procedure.

Keywords: diagnostic yield; pulmonary nodule; robotic-assisted bronchoscopy.

Graphical abstract

Figure 1

Flow chart showing the distribution of diagnostic and nondiagnostic cases as reflected by the diagnostic yield algorithm. ^aBoth lesions proven malignant by subsequent sampling. ^bNine lesions proven malignant by subsequent sampling, 2 lesions proven benign by subsequent sampling, 7 lesions regressed or resolved on follow-up imaging, 2 lesions increased in size on follow-up imaging, and 2 lesions had insufficient (<1 year) follow-up imaging to confirm stability. ^cTwo lesions proven malignant by subsequent sampling and one lesion regressed on follow-up imaging.

Figure 2

Bar graph showing diagnostic yield as reflected by the distribution of lesions by size.

Figure 3

Pie chart showing the distribution of lesion diagnoses (N = 159). ^aIsolated organisms included nontuberculous mycobacteria (n = 3), Pseudomonas aeruginosa (n = 2), Nocardia species (n = 2), Aspergillus species (n = 2), Mycobacterium TB (n = 1), Streptococcus pneumoniae (n = 1), and Chryseobacterium species (n = 1). ^bPatterns of inflammation included chronic inflammation (n = 10), granulomatous inflammation (n = 8), organizing pneumonia (n = 3), eosinophilic inflammation (n = 3), and acute or neutrophilic inflammation (n = 3). ^cOf 22 insufficient samplings, 11 proved malignant by subsequent sampling or excision, two proved benign by subsequent sampling or excision, seven regressed or resolved on follow-up imaging, two increased in size on follow-up imaging, and two had insufficient follow-up imaging to define stability. ^dLesion was compatible with granulomatous inflammation. ^eOf three samplings revealing atypical cells not further classified, two proved malignant by subsequent sampling and one regressed on follow-up imaging. ^fProven adenocarcinoma of the lung by CT scan-guided transthoracic biopsy. NOS = not otherwise specified; NSCLC = non-small cell lung cancer; ssRAB = shape-sensing robotic-assisted bronchoscopy.