Abstract Background There are multiple bronchoscopic technologies available to biopsy peripheral pulmonary lesions (PPLs), including robotic assisted bronchoscopy (RAB) and electromagnetic navigational bronchoscopy (ENB). A recently published randomized controlled trial, RELIANT (NCT05705544; PMID 40460390), demonstrated comparable diagnostic yields and complication rates between these platforms. However, RELIANT was conducted at a single, high-volume academic medical center with experienced operators. Additionally, while the ENB platform utilized fully integrated digital tomosynthesis (DT) for intraprocedural PPL localization, the RAB platform was not integrated with intraprocedural cone-beam computed tomography (CBCT), and manual targeting adjustments were required. As RAB is now fully integrated with CBCT, we designed RELIANT 2 to address these limitations and evaluate the performance of modern RAB-CBCT compared to legacy ENB-DT. Methods Robotic versus Electromagnetic Bronchoscopy for Pulmonary LesIon AssessmeNT using integrated intraprocedural imaging (RELIANT 2) is an investigator-initiated, multicenter, open label, superiority, cluster randomized trial. Adult patients undergoing navigational bronchoscopy for evaluation of PPLs meeting all eligibility criteria were enrolled. Procedure rooms were randomly assigned to either RAB-CBCT or ENB-DT, with each procedure room-day considered a cluster. Sealed opaque envelopes were used to conceal the allocation from schedulers, proceduralists, and patients until the morning of procedure when each room was randomly assigned to a platform. The primary endpoint is diagnostic yield, defined as the proportion of cases resulting in a specific benign or malignant diagnosis per recent ATS/ACCP consensus statement. Secondary and safety endpoints include procedure duration and procedural complications. A sample size of 440 patients in approximately 220 clusters provides an 80% power to detect a 10% increment in diagnostic yield (80% for ENB-DT and 90% for RAB-CBCT) at a two-sided type I error rate of 5%, with intracluster correlation of 0.1 (based on data from RELIANT). The study was approved at participating institutions and registered in ClinicalTrials.gov (NCT06654271) prior to patient enrollment. An independent Data and Safety Monitoring Board was appointed to oversee the study and review one prespecified interim analysis. Results The study open on November 11, 2024, and completed enrollment on October 7, 2025. A total of 440 patients were enrolled in the trial. Discussion RELIANT 2 is a multicenter cluster randomized trial that compares the diagnostic yield of RAB-CBCT to that of ENB-DT in patients undergoing bronchoscopy to biopsy PPLs. This trial will assess the impact of integrated intraprocedural imaging and help address some of the limitations of the recently published RELIANT trial. This abstract is funded by: ATS
Paez et al. (Fri,) studied this question.