Navigation Endobronchial Ultrasound

Background:

Despite recent years' improvement regarding the treatment of lung cancer, it remains the leading cause of cancer deaths in Denmark. This is partly due to many patients being diagnosed in an advanced stage limiting the possibilities of curative treatment. Much attention has therefore been aimed at developing tools for early identification of patients with possible lung cancer . Screening or easy access to CT of the chest may help to identify patients with possible early stage lung cancer. Performing biopsies of small lung lesions in a safe manner without inexpedient complications, however, is an ongoing diagnostic challenge especially for the increasing elderly patient population and patients with decreased lung function. If patients are to benefit from an improved identification of possible early stage lung cancer, it is necessary to also further improve the methods for obtaining biopsies in this patient population in order to decrease the morbidity during the diagnostic work-up and to prepare the patients for treatment in a secure manner.

Current methods for performing biopsies of small lung lesions are transthoracic, endoscopic or surgical. When compared to surgery, the endoscopic methods have the advantages of being easily accessible, cheap, safe with a very low risk of complications, and have limited patient discomfort following the procedure. The major drawback is the diagnostic yield still being significantly lower than surgery.

In recent years, two methods have been developed which seem to improve the diagnostic yield of bronchoscopy for diagnosing peripheral lung lesions. The rationale behind both techniques is to improve identification of the lung lesions prior to performing the biopsies and thereby improving the chance of obtaining representative tissue samples. One method involves the use of a radial ultrasound probe inserted in the working channel of the bronchoscope, which enables the proceduralist to perform radial endobronchial ultrasound (rEBUS) to more accurately identify the lung lesions before sampling them. The other method involves the use of electromagnetic navigation bronchoscopy (ENB) to guide the operator to the lung lesion. One small randomised clinical trial has indicated that the diagnostic yield can be further improved by a multimodal approach, which combines both rEBUS and ENB in the same procedure. The drawbacks of such a combination are however increased costs and procedure time, thus limiting the number of procedures which can be performed within a given time frame.

This PhD thesis aims to determine whether a combination of rEBUS and ENB is superior to ENB alone in patients with suspected lung cancer due to a peripheral lung lesion as well as an estimate of the hospital costs of the entire diagnostic work up for lung cancer when combining ENB and rEBUS as compared to ENB alone.

Hypotheses:

1. The diagnostic yield of ENB in combination with rEBUS is equal to ENB alone in patients with peripheral lung lesions or solitary lung nodules (null hypothesis)
2. The hospital costs of the entire diagnostic work up for lung cancer when combining ENB and rEBUS is the same when compared to an approach with ENB alone (null hypothesis)

Research questions:

1. Is the diagnostic yield of ENB in combination with rEBUS different from ENB alone in diagnosing lung lesions?
2. What are the hospital costs of the entire diagnostic workup for lung cancer when combining ENB and rEBUS in comparing with ENB alone?

Navigation EndoBronchial ULtrAsound (NEBULA):

Hypotheses The study examines the following null-hypothesis: The diagnostic yield of ENB in combination with rEBUS is not superior to ENB alone in patients with peripheral lung lesions or solitary lung nodules.

Objectives To determine which bronchoscopy approach should be considered standard for examining patients with suspected lung cancer due to a peripheral lung lesion.

Methods Study design Multicentre, randomized, non-blinded clinical trial Pre- and post-procedure Preparations prior and following the bronchoscopy procedure are done in accordance with local guidelines. Procedures will be performed either under conscious sedation using midazolam and fentanyl or in general anesthetic depending on the set up of the center performing the procedures. Other medication given during the procedure is also given accordance with local guidelines.

Reference test Histology or cytology results will be used as the reference test for all malignant as well as non-malignant conditions that could be diagnosed based on these. Clinical follow-up including imaging for at least 6 months with no signs of malignancy and results of additional diagnostic procedures will be used as the reference test in patients in which a final diagnosis cannot be established based on histology or cytology results.

Sample size and statistics In a previous study by Eberhardt et al. the diagnostic yield of ENB and combined rEBUS/ENB was 59 % and 88 %, respectively. The diagnostic yield of the intervention arm in the planned study may be lower due to selection of patients with smaller lesions and multicentre approach rather than a single centre study performed by experts. If the total diagnostic yield is 60 % in the control group (ENB) and 80 % in the intervention group (rEBUS/ENB), then a power of 80 % at the 5 % level is obtained with a sample size of 184 patients. Allowing for a 10 % dropout it is planned to enroll 200 patients in the study. The χ2 test, alternatively the Fischer exact test will be used to establish whether there is a difference in the primary endpoint. All results will be assessed using intention to treat principles.

Ethics:

The studies and analyses will be conducted in accordance with the amended Declaration of Helsinki and Data Protection Agency in Denmark and the Medical Ethics Committee.:

The studies do not interfere with choice of other diagnostic tests performed in the patients (e.g. EBUS / EUS-b for mediastinal staging). The patients are treated and followed up according to national and institutional guidelines. The protocols for studies II and III do not influence treatment or follow-up.

Clinical relevance:

The results will help to clarify how one of the most important diagnostic procedures for patients with suspected lung cancer due to a peripheral lung lesion should be used in clinical practice. The results of the project can be directly implemented at a national scale once the results are available.

Economy:

Project expenses are expected to be partially covered by funds from the Kræftens Bekæmpelse - Centre for Lung Cancer Research with a grant of 1 mill. DKK. Funding of expenses for procedures (e.g. scans and invasive procedures) will be covered as part of the lung cancer diagnostic work up "package" covered by the department.

Participating departments:

Currently the following departments have agreed to participate:

• Department of Respiratory Medicine, Bispebjerg Hospital
• Department of Respiratory Medicine, Aalborg University Hospital
• Department of Respiratory Medicine, Odense University Hospital