In the last few years, advances in bronchoscopy-related technologies have led to numerous studies evaluating their performance. While “diagnostic yield” is the most common end point in these studies, there is considerable variation in its exact definition across studies.
A “liberal” diagnostic yield definition has been commonly used in the past.1 It not only considers malignant and “specific” benign diagnoses (eg, granulomatous inflammation, organizing pneumonia, etc) diagnostic but also permits classifying “nonspecific” benign findings as diagnostic, provided radiographic stability or regression is established for a variable (12 to 24 months) period.2 This methodology, which allows for the incorporation of radiographic follow-up into the diagnostic yield definition, is in line with clinical practice, whereby, in the appropriate clinical context, nonspecific benign diagnoses can often be safely followed up radiographically.
Critics of the liberal definition, however, point out several limitations, which prompted the American College of Chest Physicians and the American Thoracic Society to propose a strict diagnostic yield definition in a consensus statement.3–5 According to this, only cases with specific malignant and benign diagnoses should be considered “diagnostic,” whereas all cases with nonspecific benign diagnoses should be classified as “nondiagnostic,” regardless of the follow-up results.
This strict definition has several advantages. First, it is patient-centered and helps reiterate the need for close follow-up in patients with nonspecific benign findings. Second, it’s validated, with a high degree of specificity.4,6 Very few cases labeled diagnostic under the strict definition would need to be revised. Third, it is efficient, allowing research results to be finalized right away rather than waiting one to two years.7
While this “strict” definition overcomes several limitations of the liberal definition, it has its own pitfalls. First, a nonspecific benign diagnosis does not necessarily indicate a failure of the biopsy modality; it may simply reflect the nature of the disease. Surgical lung biopsy is considered the gold standard, but John M. Archer, MD, and colleagues found that focal fibrosis/scar, nonspecific inflammation, and reactive hyperplasia accounted for 63% of all resected benign nodules.8 The strict definition would label such lesions as nondiagnostic, which may unnecessarily lead to repeat biopsy procedures, patient anxiety, and costs.
Second, while the presence of granulomatous inflammation and organizing pneumonia on biopsy would be considered diagnostic under the strict definition, this should not obviate the need for radiographic follow-up, as these pathologies are known to coexist with cancer.9–10
Third, since it’s impossible to arrive at a specific benign diagnosis in a significant number of truly benign lesions, a strict definition would make the diagnostic yield dependent on the cancer prevalence in the study population rather than on the inherent qualities of the biopsy modality itself.
Both diagnostic yield definitions have their own advantages and disadvantages. While a liberal definition might be more clinically pragmatic, a strict definition offers greater academic rigor and consistency across studies assessing novel bronchoscopy modalities. Reporting both allows readers to make more informed inferences.11 Other parameters, such as “tool-in-lesion,” are important technical procedural outcomes, but they are not patient-centered and therefore not substitutes for diagnostic yield per se.
References
1. Ali MS, Ghori UK, Wayne MT, et al. Diagnostic performance and safety profile of robotic-assisted bronchoscopy: a systematic review and meta-analysis. Ann Am Thorac Soc. 2023;20(12):1801-1812. doi:10.1513/AnnalsATS.202301-075OC
2. Funes-Ferrada R, Barrios-Ruiz A, Yu Lee-Mateus A, et al. Narrative review of diagnostic yield of navigational bronchoscopy for pulmonary nodules-a call for standardization. J Thorac Dis. 2025;17(7):5361-5370. doi:10.21037/jtd-24-1469
3. Paez R, Lentz RJ, Duke JD, et al. Robotic versus electromagnetic bronchoscopy for peripheral pulmonary lesions: a randomized trial (RELIANT). Am J Respir Crit Care Med. 2025;211(9):1644-1651. doi:10.1164/rccm.202409-1846OC
4. Lentz RJ, Frederick-Dyer K, Planz VB, et al. Navigational bronchoscopy or transthoracic needle biopsy for lung nodules. N Engl J Med. 2025;392(21):2100-2112. doi:10.1056/NEJMoa2414059
5. Gonzalez AV, Silvestri GA, Korevaar DA, et al. Assessment of advanced diagnostic bronchoscopy outcomes for peripheral lung lesions: a delphi consensus definition of diagnostic yield and recommendations for patient-centered study designs. An official American Thoracic Society/American College of Chest Physicians research statement. Am J Respir Crit Care Med. 2024;209(6):634-646. doi:10.1164/rccm.202401-0192ST
6. Leonard KM, Low S-W, Echanique CS, et al. Diagnostic yield vs diagnostic accuracy for peripheral lung biopsy evaluation: evidence supporting a future pragmatic end point. Chest. 2024;165(6):1555-1562. doi:10.1016/j.chest.2023.12.024
7. Murgu S, Chen AC, Gilbert CR, et al. A prospective, multicenter evaluation of safety and diagnostic outcomes with robotic-assisted bronchoscopy: results of the transbronchial biopsy assisted by robot guidance in the evaluation of tumors of the lung (TARGET) trial. Chest. 2025;168(2):539-555. doi: 2025;168(2):539-555. doi:10.1016/j.chest.2025.04.022
8. Archer JM, Mendoza DP, Hung YP, et al. Surgical resection of benign nodules in lung cancer screening: incidence and features. JTO Clin Res Rep. 2023;4(12):100605. doi:10.1016/j.jtocrr.2023.100605
9. Eguchi T, Takasuna K, Fujiwara M, et al. Coexistence of a pulmonary adenocarcinoma with a focal organizing pneumonia. Interact Cardiovasc Thorac Surg. 2011;13(4):444-446. doi:10.1510/icvts.2011.275065
10. Dagaonkar RS, Choong CV, Asmat AB, et al. Significance of coexistent granulomatous inflammation and lung cancer. J Clin Pathol. 2017;70(4):337-341. doi:10.1136/jclinpath-2016-204221
11. Abdelghani R, Espinoza D, Uribe JP, et al. Cone-beam computed tomography-guided shape-sensing robotic bronchoscopy vs. electromagnetic navigation bronchoscopy for pulmonary nodules. J Thorac Dis. 2024;16(9):5529-5538. doi:10.21037/jtd-24-178
