Early detection of bronchial lesions using newly developed videoendoscopy-based autofluorescence bronchoscopy
Introduction
The key to early detection is viewed as the holy grail in the search for the development of a powerful strategy to effectively treat, and ultimately eliminate the most lethal malignant disease worldwide: lung cancer. The majority of patients are diagnosed to have lung cancer in a late stage in which curative treatment cannot be expected. Nevertheless, most central type early stage lung cancers can be successfully treated by endoscopic methods such as photodynamic therapy (PDT) [1], [2], [3], therefore thoracotomy has been replaced by such less invasive treatments in this field since the early 1990s. Bronchoscopy is one of the representative modalities for early detection of lung cancer, and the last decade has witnessed several advances in both the technical and clinical aspects of bronchology, leading to better diagnostic and therapeutic yields. Advances in technology produced new clinically beneficial developments, in particular, autofluorescence bronchoscopy (AF) [4], [5], [6], [7], [8], and endobronchial ultrasonography [9]. Autofluorescence diagnosis has become increasingly adopted since the early 1990s and several studies have shown that it improved the sensitivity of detection of cancerous and precancerous lesions of the airway compared to white light (WL) bronchoscopy, especially in cases in the intraepithelial stage [4], [5], [6], [7], [8]. Genetic abnormalities have been recognized in the dysplastic lesions as well as ostensibly normal sites of heavy smokers [10], [11]. Bronchial mucosa contains huge amount of carcinogenic process information useful for the management of individuals at high risk. Moreover, the fiberoptic bronchoscope has been replaced by the videoendoscope, with which bronchoscopists can capture more detailed findings of the bronchus. However, most previous studies regarding autofluorescence diagnosis compared the diagnostic performance of bronchofiberscopy and autofluorescence bronchoscopy. Here we report the performance of a revolutionary autofluorescence bronchoscopy combined with videoendoscopy system as well as its preliminary results.
Section snippets
Study subjects
The entry criteria for enrollment, described below, were similar to previous studies of autofluorescence bronchoscopy [4], [5], [6], [7], [8].
- (1)
Patients with known or suspected lung cancer scheduled for bronchoscopy as a part of their standard work up.
- (2)
Patients with abnormal sputum cytology findings (moderate atypia or worse) with a normal chest radiograph.
- (3)
Patients after curative surgery for stage I lung cancer scheduled for bronchoscopy as a part of their follow up.
- (4)
Current or former smokers with
Autofluorescence bronchoscopy
The system used was the SAFE 3000 (Pentax, Tokyo, Japan), which consisted of a color CCD videoendoscopy-based AF system. In SAFE 3000, two light sources are available. One is a xenon lamp for white light image and the other is a diode laser which works as an AF mode excitation light source. Infrared light is eliminated by an infrared cut filter and white light is collected by the lens and transmitted to the objects through the light guide of the videoendoscope (Fig. 1). In the AF mode, the
Diagnosis
Of the total of 170 biopsy specimens, 4 were not evaluable due to lack of epithelium. The final pathological diagnosis of the remaining 166 biopsy specimens were as follows: normal, inflammation, hyperplasia, metaplasia with no atypia 88, dysplasia 29 (mild 4, moderate 24, severe 1), carcinoma in situ (CIS) 19, and invasive cancer 30, respectively. The relationship between endoscopic findings and pathological results is shown in Table 2.
The 19 invasive cancer lesions were equally diagnosed by
Discussion
This study demonstrated a higher diagnostic rate of intraepithelial lesions of the bronchus using the newly developed videoendoscopy-based AF compared to WL videoendoscopy alone.
Early detection of intraepithelial lesions is one of the main interests of bronchoscopists. The Japan Lung Cancer Society classified the endoscopic findings of central type early stage lung cancer into five groups: invisible type, hypertrophic type, nodular type, polypoid type, and mixed type [13].
Among these, the
Acknowledgements
The authors thank Professor J. Patrick Barron, International Medical Communications Center, Tokyo Medical University, for his support in reviewing this manuscript. Bronchoscopy system (The SAFE 3000) was supported by Pentax (Tokyo, Japan). There was no other financial support for the authors.
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