High Definition bronchoscopy, an exploratory study of diagnostic value in comparison to standard white light bronchoscopy and autofluorescence bronchoscopy

Bronchoscopy is one of the most important procedures in diagnosis of lung
cancer and other pulmonary diseases. This procedures renders important
anatomical information and subtle changes in the epithelium or vascularity of
the bronchial tree are clues to guide the endoscopist in this procedure,
especially in case of centrally located lung cancer. These subtle changes may
influence the choice of treatment, site of biopsy and resectability of lung
cancers when determining resection margins but also in case of multifocal
premalignant disease. A recently published meta-analysis has shown diagnostic
superiority of autofluorescence bronchoscopy (AFB) over routine white light
bronchoscopy (WLB).
Through technological improvement a new technique has become available in the
form of high-definition (HD-) bronchoscopy. Current normal video white light
bronchoscopy is the standard, and video-autofluorescence bronchoscopy is
offered by specialised centers only.
The impact of this development with high-definition videobronchoscopy using a
1.1 megapixel chip on the diagnostic performance of bronchoscopy is however
unkown.

(1) Investigate diagnostic performance (sensitivity) of HD bronchoscopy, with
or without surface enhancement or tone enhancement in comparison to standard
WLB for detecting abnormalities of the tracheobronchial tree. Furthermore we
aim to investigate determination of resection margins of (suspected)
malignancies in the glottic and supraglottic area or centrally located lung
cancer in comparison to (SAFE 3000) autofluorescence bronchoscopy in a high
risk population with biopsies from all suspect lesions identified by either
technique.
(2) When the sensitivity and specificity of HD videobronchoscopy in either mode
in the abovementioned study is in the vicinity of the reported sensitivity and
specificity of SAFE3000 dual mode videobronchoscopy we suggest to use the
results of this study to perform a power analysis. With this information it may
then be possible to design a new future study to compare sensitivity for
detecting premalignant lesions in a high risk population in a prospective
study.

(1) Prior to surgery by the ENT surgeon or cardiothoracic surgeon bronchoscopy
will be performed by an experienced chest physician through a laryngeal mask
under general anaesthesia.

Bronchoscopy will be performed in a standardized order using five different
imaging modes. The order of the different modes will be randomized.
High-definition digital videos will be made from all procedures without in
screen indications of date, time or reference to study site or patient
identification. The five imaging modes used in this study are:
1. Standard white light videobronchoscopy (WLB)
2. High Definition (HD)-Bronchoscopy
3. HD-bronchoscopy + surface enhancement
4. HD-bronchoscopy + tone enhancement
5. Auto Fluorescence Bronchoscopy (AFB - SAFE3000) in dual video mode

All visible abnormalities suspected for malignancy or pre-malignancy will be
biopsied afterwards. The HD-digital video*s will be reviewed by the experienced
bronchoscopists in random order and blinded for patient, study site and date
and scored using a predefined scoring system to describe surface, vascularity
and tumours. Premalignant lesions identified by multiple techniques are
considered as non-inferior.

From each patient 5 HD- films will be generated. These films will be reviewed
in a blinded fashion and random order by two experienced pulmonologists and an
independent equally experienced third pulmonologist.
These videos will be scored on epithelial changes, vascularity changes,
presence or suspicion of dysplasia, presence of suspicion of carcinoma in situ,
and tumor margins.

When new clinically relevant abnormalities are found, the impact of these
findings on the planned diagnostic or therapeutic procedure will be registered.

At the start of the general anaesthesia for the planned operation a laryngeal
mask airway is inserted by the anesthesiologist.
Bronchoscopy is then performed by a very experienced pulmonologist using
routine topical anesthetics. In this way the burden for the patient and the
risk of complications is very low. These patients have an indication for the
planned procedure and have been evaluated by an anesthesiologist prior to the
procedure and are considered fit for surgery. The total anesthesia time for the
planned procedure will be increased by 10 to 15 minutes.
Bronchoscopy is a very safe diagnostic procedure, the reported complications
are in general attributable to te more invasive diagnostic procedures performed
during that diagnostic bronchoscopy like biopsy, lavage and needle aspirations.
This is not the aim of this study, invasive diagnostic procedures will only be
performed in case of a clinically relevant new finding.
In general we expect that the vast majority of the patients involved will not
have any benefit of participating in this study.