Fluorescence Bronchoscopy in High-Risk Patients: A Comparison of LIFE and Pentax Systems

Diagnosis and treatment of bronchial intraepithelial neoplasia and early lung cancer of the central airways: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Bronchial intraepithelial lesions may be precursors of central airway lung carcinomas. Identification and early treatment of these preinvasive lesions might prevent progression to invasive carcinoma.

METHODS

We systematically reviewed the literature to develop evidence-based recommendations regarding the diagnosis and treatment of intraepithelial lesions.

RESULTS

The risk and timeline for progression of bronchial intraepithelial lesions to carcinoma in situ (CIS) or invasive carcinoma are not well understood. Multiple studies show that autofluorescence bronchoscopy (AFB) is more sensitive that white light bronchoscopy (WLB) to identify these lesions. In patients with severe dysplasia or CIS in sputum cytology who have chest imaging studies showing no localizing abnormality, we suggest use of WLB; AFB may be used as an adjunct when available. Patients with known severe dysplasia or CIS of central airways should be followed with WLB or AFB, when available. WLB or AFB is also suggested for patients with early lung cancer who will undergo resection for delineation of tumor margins and assessment of synchronous lesions. However, AFB is not recommended prior to endobronchial therapy for CIS or early central lung cancer. Several endobronchial techniques are recommended for the treatment of patients with superficial limited mucosal lung cancer who are not candidates for resection.

CONCLUSION

Additional information is needed about the natural history and rate of progression of preinvasive central airway lesions. Patients with severe dysplasia or CIS may be treated endobronchially; however, it remains unclear if these therapies are associated with improved patient outcomes.

Early lung cancer: methods for detection

Early detection and surgical resection are essential for the treatment of lung cancer. It would be ideal to be able to detect and treat preinvasive bronchial lesions, defined as dysplasia and carcinoma in situ before progressing to invasive cancer. Advanced airway-assessment techniques have opened an avenue for early detection and surveillance of endobronchial malignancy. This article reviews currently available advanced imaging techniques for early detection of lung cancer, including autofluorescence bronchoscopy, narrow-band imaging, high-magnification bronchovideoscopy, endobronchial ultrasonography, and optical coherence tomography. Also discussed are the more recently developed endocytoscopy system and confocal fluorescence microendoscopy, currently used only for research purposes.

LED light source for fluorescence endoscopy using quantum dots

We present an LED light source for use with standard clinical endoscopes to enable visualization of tissues labeled with quantum dots (QDs). QD-assisted endoscopy may improve the outcome of surgical endoscopic procedures by identifying specific tissue types. QDs offer several advantages over current fluorescent stains due to their high target selectivity, long-lasting fluorescence, large excitation and narrow emission bands, and multiplexing capabilities. The prototype presented is compact, modular in design, and was built at low cost making it competitive with commercially available light sources. The device's efficiency is evaluated by measuring light intensity at discreet locations and by successfully illuminating a chicken tissue sample non-specifically labeled with a 250nM or 500nM QD solution. Ultimately, this device serves as a step towards incorporating QDs into real time, image-guided surgical procedures.

Detection and localization of intraepithelial neoplasia and invasive carcinoma using fluorescence-reflectance bronchoscopy: an international, multicenter clinical trial

OBJECTIVES

The primary objective of this study was to evaluate the benefit of using a new fluorescence-reflectance imaging system, Onco-LIFE, for the detection and localization of intraepitheal neoplasia and early invasive squamous cell carcinoma. A secondary objective was to evaluate the potential use of quantitative image analysis with this device for objective classification of abnormal sites.

DESIGN

This study was a prospective, multicenter, comparative, single arm trial. Subjects for this study were aged 45 to 75 years and either current or past smokers of more than 20 pack-years with airflow obstruction, forced expiratory volume in 1 second/forced vital capacity less than 75%, suspected to have lung cancer based on either sputum atypia, abnormal chest roentgenogram/chest computed tomography, or patients with previous curatively treated lung or head and neck cancer within 2 years.

MATERIALS AND METHODS

The primary endpoint of the study was to determine the relative sensitivity of white light bronchoscopy (WLB) plus autofluorescence-reflectance bronchoscopy compared with WLB alone. Bronchoscopy with Onco-LIFE was carried out in two stages. The first stage was performed under white light and mucosal lesions were visually classified. Mucosal lesions were classified using the same scheme in the second stage when viewed with Onco-LIFE in the fluorescence-reflectance mode. All regions classified as suspicious for moderate dysplasia or worse were biopsied, plus at least one nonsuspicious region for control. Specimens were evaluated by the site pathologist and then sent to a reference pathologist, each blinded to the endoscopic findings. Positive lesions were defined as those with moderate/severe dysplasia, carcinoma in situ (CIS), or invasive carcinoma. A positive patient was defined as having at least one lesion of moderate/severe dysplasia, CIS, or invasive carcinoma. Onco-LIFE was also used to quantify the fluorescence-reflectance response (based on the proportion of reflected red light to green fluorescence) for each suspected lesion before biopsy.

RESULTS

There were 115 men and 55 women with median age of 62 years. Seven hundred seventy-six biopsy specimens were included. Seventy-six were classified as positive (moderate dysplasia or worse) by pathology. The relative sensitivity on a per-lesion basis of WLB + FLB versus WLB was 1.50 (95% confidence interval [CI], 1.26-1.89). The relative sensitivity on a per-patient basis was 1.33 (95% CI, 1.13-1.70). The relative sensitivity to detect intraepithelial neoplasia (moderate/severe dysplasia or CIS) was 4.29 (95% CI, 2.00-16.00) and 3.50 (95% CI, 1.63-12.00) on a per-lesion and per-patient basis, respectively. For a quantified fluorescence reflectance response value of more than or equal to 0.40, a sensitivity and specificity of 51% and 80%, respectively, could be achieved for detection of moderate/severe dsyplasia, CIS, and microinvasive cancer.

CONCLUSIONS

Using autofluorescence-reflectance bronchoscopy as an adjunct to WLB with the Onco-LIFE system improves the detection and localization of intraepitheal neoplasia and invasive carcinoma compared with WLB alone. The use of quantitative image analysis to minimize interobserver variation in grading of abnormal sites should be explored further in future prospective clinical trial.

Autofluorescence bronchoscopy: quantification of inter-patient variations of fluorescence intensity

Autofluorescence (AF) from bronchial tissue is increasingly used for the endoscopic detection of early bronchial neoplasia. Several imaging systems are commercially available, all detecting the absolute or relative AF intensity and/or spectral contrasts between normal tissue and early neoplastic lesions. These devices have a high sensitivity for flat neoplasia, but the specificity remains limited. Variations in the AF intensity between individuals (inter-patient variations) is considered one of the most limiting factors. In the clinical study presented here, we quantified those variations using a non-invasive optical reference positioned in situ during AF bronchoscopy. The inter-patient variations in intensity on the main carina were in the order of 25- 30%. The results of this study are quite useful for improving and defining the design of the optical features (dynamic range, physical sensitivity) of AF detection systems.

Optimized autofluorescence bronchoscopy using additional backscattered red light

Autofluorescence bronchoscopy (AFB) has been shown to be a highly sensitive tool for the detection of early endobronchial cancers. When excited with blue-violet light, early neoplasia in the bronchi tend to show a decrease of autofluorescence in the green region of the spectrum and a relatively smaller decrease in the red region of the spectrum. Superposing the green foreground image and the red background image creates the resultant autofluorescence image. Our aim was to investigate whether the addition of backscattered red light to the tissue autofluorescence signal could improve the contrast between healthy and diseased tissue. We have performed a clinical study involving 41 lung cancers using modified autofluorescence bronchoscopy systems. The lesions were examined sequentially with conventional violet autofluorescence excitation (430 nm+/-30 nm) and violet autofluorescence excitation plus backscattered red light (430 nm+/-40 nm plus 665 nm+/-15 nm). The contrast between (pre-)neoplastic and healthy tissue was quantified with off-line image analysis. We observed a 2.7 times higher contrast when backscattered red light was added to the violet excitation. In addition, the image quality was improved in terms of the signal-to-noise ratio (SNR) with this spectral design.

Bronchial Intraepithelial Neoplasia/Early Central Airways Lung Cancer

BACKGROUND

An evidence-based approach is necessary for the localization and management of intraepithelial and microinvasive non-small cell lung cancer in the central airways.

METHODS

Material appropriate to this topic was obtained by literature search of a computerized database. Recommendations were developed by the writing committee and then reviewed by the entire guidelines panel. The final recommendations were made by the Chair and were voted on by the entire committee.

RESULTS

White light bronchoscopy has diagnostic limitations in the detection of microinvasive lesions. Autofluorescence bronchoscopy (AFB) is a technique that has been shown to be a sensitive method for detecting these lesions. In patients with moderate dysplasia or worse on sputum cytology and normal chest radiographic findings, bronchoscopy should be performed. If moderate/severe dysplasia or carcinoma in situ (CIS) is detected in the central airways, then bronchoscopic surveillance is recommended. The use of AFB is preferred if available. In a patient being considered for curative endobronchial therapy to treat microinvasive lesions, AFB is useful. A number of endobronchial techniques as therapeutic options are available for the management of CIS and can be recommended to patients with inoperable disease. In patients with operable disease, surgery remains the mainstay of treatment, although patients may be counseled about these techniques.

CONCLUSIONS

AFB is a useful tool for the localization of microinvasive neoplasia. A number of endobronchial techniques available for the curative treatment can be considered first-line therapy in inoperable cases. For operable cases, the techniques may be considered and discussed with the patients.

Fluorescent bronchoscopy: contribution for lung cancer screening?

The majority of early lesions, even when centrally located, is missed by conventional white-light (WL) bronchoscopy. Fluorescent bronchoscopy is a promising tool in localising early malignant changes in the central airways, because it is significantly more sensitive than WL bronchoscopy. Originally, drug-induced fluorescence has been used, but today autofluorescence bronchoscopy is more common in relation to its simplicity and advantages. Different systems are available which yield comparable results. However, there are no studies comparing all systems. The disadvantage is the low specificity of the method. Fluorescent bronchoscopy will be more effective if carried out in high-risk patients and/or embedded in a program of preprocedural evaluation of sputum and together with a CT examination of the thorax. But a reduction of mortality as a result of such efforts has not been shown until the present time.