Confocal Laser Endomicroscopy VERification

Rationale: Lung cancer screening and the increasing use of chest-computed tomography (CT) has led to an increase in the number of (incidental) found suspected malignant lung lesions. Since tissue acquisition for pathological analysis is prerequisite for diagnosis and optimal treatment, a drastic increase in the number of patients that need to undergo bronchoscopy is expected.

Over 70% of the suspected lesions develop in the periphery of the lung and are therefore not visible during conventional bronchoscopy. Although several bronchoscopic navigational techniques demonstrated an improved navigation towards the target lesion, the diagnostic yield remains suboptimal due to a substantial near-miss rate. As a result, the need for complementary bronchoscopic guidance that provides real-time feedback on the correct positioning of the biopsy instruments is urgent.

Needle-based Confocal laser endomicroscopy (nCLE) is a novel high-resolution imaging technique that uses an excitation laser light to create 'real-time' microscopic images of tissues. nCLE can be integrated into the biopsy needle, allowing real-time cancer detection at the tip of the biopsy needle during bronchoscopy. The confocal microscope captures autofluorescence of tissues or, combined with intravenously (IV) infused fluorophores (such as fluorescein) allows imaging of individual tumor cells. Recent studies on nCLE-imaging in lung tumors and metastatic lymph nodes have identified and validated nCLE criteria for malignancy (enlarged pleomorphic cells, dark clumps and directional streaming) and airway/lung parenchyma (alveoli, elastin fibres of the conducting airway, bronchial epithelium and still image) and granulomas. A recent study demonstrated that these nCLE-criteria can be used in real-time to fine-tune the needle positioning during ongoing bronchoscopy and thereby potentially improve the diagnostic yield.

This randomized controlled trials aims to evaluate the added value of nCLE-imaging (smart needle) to the conventional used bronchoscopic approach for peripheral lung lesion analysis.

Objective: This multicenter, randomized controlled trial, aims to investigate if nCLE-imaging integrated with conventional bronchoscopy results in a higher diagnostic yield compared to conventional bronchoscopy without nCLE in the diagnosis of peripheral lung nodules.

Study design: Investigator-initiated, international, multi-center randomized controlled trial including university and general hospitals.

Study population: Patients (>18 years old) with suspected malignant peripheral lung lesions with an indication for bronchoscopic analysis.

Procedure: Bronchoscopy will be performed according to institutional practice, including radial endobronchial ultrasound (r-EBUS) and optionally fluoroscopy, electromagnetic navigation, virtual bronchoscopy and/or ultrathin bronchoscopy. This is followed by transbronchial needle aspiration (TBNA) and (cryo-)biopsies (control arm). In the study arm, nCLE-imaging will be added prior to TBNA tissue acquisition to fine-tune the sampling area. Cytology staining for rapid onsite evaluation (ROSE) and cellblock will be performed according to local practice.

Primary objective:

To determine if the addition of nCLE-imaging to conventional bronchoscopic peripheral lung lesion analysis results in an improved diagnostic yield. (defined as the proportion of patients in whom the bronchoscopic procedure results in a definitive diagnosis out of the total number of patients that have received the diagnostic bronchoscopic procedure).

Inclusion criteria

• ≥18 years of age
• Suspected malignant peripheral lung lesion with an indication for a bronchoscopic diagnostic work-up as determined by the attending physician or tumor board. Peripheral pulmonary lesions are defined as lesions located beyond the visible segmental bronchi, not detectable by regular flexible bronchoscopy
• Bronchus sign on pre-procedural CT or estimated confidence for successful navigation to the nodule resulting in a r-EBUS signal
• Solid part of the lesion must be ≧10 mm
• Largest dimension of lesion size on CT ≦30 mm (long-axis)
• Ability to understand and willingness to sign a written informed consent

Exclusion criteria

• Inability or non-willingness to provide informed consent
• Endobronchial visible malignancy on bronchoscopic inspection
• Target lesion within reach of the linear EBUS scope
• Failure to comply with the study protocol
• Known allergy or risk factors for an allergic reaction to fluorescein
• Pregnancy or breastfeeding
• Hemodynamic instability
• Refractory hypoxemia
• Therapeutic anticoagulant use that cannot be withheld for an appropriate interval before the procedure
• Unable to tolerate general anesthesia according to the anesthesiologist
• Undergoing chemotherapy as several chemotherapies have fluorescent properties at the same wavelength (e.g., doxorubicin)