Localization of bronchial intraepithelial neoplastic lesions by fluorescence bronchoscopy

Fluorescence and tracers in surgery: the coming future

The revolution that we are seeing in the world of surgery will determine the way we understand surgical approaches in coming years. Since the implementation of minimally invasive surgery, innovations have constantly been developed to allow the laparoscopic approach to go further and be applied to more and more procedures. In recent years, we have been in the middle of another revolutionary era, with robotic surgery, the application of artificial intelligence and image-guided surgery. The latter includes 3D reconstructions for surgical planning, virtual reality, holograms or tracer-guided surgery, where ICG-guided fluorescence has provided a different perspective on surgery. ICG has been used to identify anatomical structures, assess tissue perfusion, and identify tumors or tumor lymphatic drainage. But the most important thing is that this technology has come hand in hand with the potential to develop other types of tracers that will facilitate the identification of tumor cells and ureters, as well as different light beams to identify anatomical structures. These will lead to other types of systems to assess tissue perfusion without the use of tracers, such as hyperspectral imaging. Combined with the upcoming introduction of ICG quantification, these developments represent a real revolution in the surgical world. With the imminent implementation of these technological advances, a review of their clinical application in general surgery is timely, and this review serves that aim.

Rapid label-free detection of early-stage lung adenocarcinoma and tumor boundary via multiphoton microscopy

Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer-related deaths in China. Rapid and precise evaluation of tumor tissue during lung cancer surgery can reduce operative time and improve negative-margin assessment, thus increasing disease-free and overall survival rates. This study aimed to explore the potential of label-free multiphoton microscopy (MPM) for imaging adenocarcinoma tissues, detecting histopathological features, and distinguishing between normal and cancerous lung tissues. We showed that second harmonic generation (SHG) signals exhibit significant specificity for collagen fibers, enabling the quantification of collagen features in lung adenocarcinomas. In addition, we developed a collagen score that could be used to distinguish between normal and tumor areas at the tumor boundary, showing good classification performance. Our findings demonstrate that MPM imaging technology combined with an image-based collagen feature extraction method can rapidly and accurately detect early-stage lung adenocarcinoma tissues.

Autofluorescence Image-Guided Endoscopy in the Management of Upper Aerodigestive Tract Tumors

At this juncture, autofluorescence and narrow-band imaging have resurfaced in the medicine arena in parallel with current technology advancement. The emergence of newly developed optical instrumentation in addition to the discovery of new fluorescence biomolecules have contributed to a refined management of diseases and tumors, especially in the management of upper aerodigestive tract tumors. The advancement in multispectral imaging and micro-endoscopy has also escalated the trends further in the setting of the management of this tumor, in order to gain not only the best treatment outcomes but also facilitate early tumor diagnosis. This includes the usage of autofluorescence endoscopy for screening, diagnosis and treatment of this tumor. This is crucial, as microtumoral deposit at the periphery of the gross tumor can be only assessed via an enhanced endoscopy and even more precisely with autofluorescence endoscopic techniques. Overall, with this new technique, optimum management can be achieved for these patients. Hence, the treatment outcomes can be improved and patients are able to attain better prognosis and survival.

Endoscopic follow-up of low-grade precancerous bronchial lesions in high-risk patients: long-term results of the SELEPREBB randomised multicentre trial

BACKGROUND

3-9% of low-grade preinvasive bronchial lesions progress to cancer. This study assessed the usefulness of an intensive bronchoscopy surveillance strategy in patients with bronchial lesions up to moderate squamous dysplasia.

METHODS

SELEPREBB (ClinicalTrials.gov NCT00213603) was a randomised study conducted in 17 French centres. After baseline lung computed tomography (CT) and autofluorescence bronchoscopy (AFB) to exclude lung cancer and bronchial severe squamous dysplasia or carcinoma in situ (CIS), patients were assigned to standard surveillance (arm A) with CT and AFB at 36 months or to intensive surveillance (arm B) with AFB every 6 months. Further long-term data were obtained with a median follow-up of 4.7 years.

RESULTS

364 patients were randomised (A: 180, B: 184). 27 patients developed invasive lung cancer and two developed persistent CIS during the study, with no difference between arms (OR 0.63, 95% CI 0.20-1.96, p=0.42). Mild or moderate dysplasia at baseline bronchoscopy was a significant lung cancer risk factor both at 3 years (8 of 74 patients, OR 6.9, 95% CI 2.5-18.9, p<0.001) and at maximum follow-up (16 of 74 patients, OR 5.9, 95% CI 2.9-12.0, p<0.001). Smoking cessation was significantly associated with clearance of bronchial dysplasia on follow-up (OR 0.12, 95% CI 0.01-0.66, p=0.005) and with a reduced risk of lung cancer at 5 years (OR 0.15, 95% CI 0.003-0.99, p=0.04).

CONCLUSION

Patients with mild or moderate dysplasia are at very high risk for lung cancer at 5 years, with smoking cessation significantly reducing the risk. Whereas intensive bronchoscopy surveillance does not improve patient outcomes, the identification of bronchial dysplasia using initial bronchoscopy maybe useful for risk stratification strategies in lung cancer screening programmes.

Lung cancer: Premalignant biology and medical prevention

Lung cancer (both adenocarcinoma and squamous cell) progress through a series of pre-malignant histologic changes before the development of invasive disease. Each of these carcinogenic cascades is defined by genetic and epigenetic alterations in pulmonary epithelial cells. Additionally, alterations in the immune response, progenitor cell function, mutational burden, and microenvironmental mediated survival of mutated clones contribute to the risk of pre-malignant lesions progressing to cancer. Medical preventions studies have been completed and current and future trials are informed by the improved understanding of pre-malignancy. This will lead to precision chemoprevention trials based on lesional biology and histologic characteristics.

Detection of a pinhole-sized bronchoesophageal fistula under bronchoscopic autofluorescence imaging

Autofluorescence imaging (AFI) is a technique for detecting early‐stage lung cancer by amplifying the difference in autofluorescence of the bronchial mucosa. However, there are few reports detailing its other applications. Here, we report the case of a 54‐year‐old woman with stage IVa esophageal cancer who completed chemoradiation therapy, but developed a bronchoesophageal fistula at the left main bronchus and underwent fasting treatment. Computed tomography confirmed that the fistula had closed; however, she subsequently developed aspiration pneumonia and underwent bronchoscopy for confirmation. Although it was difficult to identify the site of the pinhole bronchoesophageal fistula under white light, AFI could easily identify the fistula and digestive mucus in light magenta. AFI may therefore be worth considering for the detection of pinhole bronchoesophageal fistulas.

Effectiveness of Velscope and Vizilite Plus Systems in Diagnostics of Oral Lesions

Aim: To compare the level of diagnostic coincidence between classical (standard) method and VELscope and ViziLite Plus systems in the diagnosis of different oral lesions.

Material and methods: 184 oral lesions were examined using classical method, VELscope and ViziLite Plus systems, and after that underwent a pathohistological examination for diagnosis proof. The percentage of diagnostic coincidence for various types of lesions was analyzed for the three methods compared.

Results: The results demonstrated the highest coincidence rate for lesions diagnosed with VELscope – 35 (83.3%), followed by those with classical method – 80 (80.8%), and those with the application of ViziLite – 33 (76.7%). In premalignant and malignant lesions, the highest percentage of diagnostic coincidence was reported using the classical method – 14 (93.3%), for non-malignant lesions using VELscope – 28 (84.8%), for inflammatory and reactive lesions using VELscope – 14 (82.4%) and for lesions associated with general disease and systemic medication again using VELscope – 11 (91.7%).

Conclusion: Non-invasive methods, tested in the study, have different diagnostic properties when differentiating particular clinical types of lesions. They are highly sensitive to changes in the oral mucosa but the final diagnosis must always be proved with biopsy.

Role of I-scan technique in screening for lung cancer in smokers with positive sputum cytology

Background

Lung cancer has a very poor prognosis and high mortality. Positive sputum for malignant and/or atypical cells warrants the need for fibreoptic bronchoscopy. White light bronchoscopy (WLB) is usually unable to detect preinvasive lesions; therefore, autofluorescence bronchoscopy (AFB) was introduced as a gold standard for detecting such lesions. The aim of this work was to investigate the role of I-scan as a screening tool for cancer in smoker patients showing positive sputum cytology.

Results

New suspicious findings under I-scan occurred in 11 patients (36.7%). The overall sensitivity of WLB alone to diagnose malignancy is 23.3%, in contrast to an added sensitivity of 50% when I-scan was combined with white light (p value < 0.05). The specificity of I-scan could not be assessed in the absence of control cases (true negatives). No major complications or deaths occurred. Haemorrhage and bronchospasm were the commonest minor complications.

Conclusions

The addition of I-scan to the routine white light examination can increase the overall sensitivity of bronchoscopic screening in cases of sputum suspicious for malignancy if put in experienced hand. The suggested increase in procedure duration due to the combined use of I-scan and white light bronchoscopy is not associated with life-threatening complications.

Feasibility of lung cancer screening in developing countries: challenges, opportunities and way forward

Lung cancer is the leading cause of all cancer deaths worldwide, comprising 18.4% of all cancer deaths. Low-dose computed tomography (LDCT) has shown mortality benefit in various trials and now a standard tool for lung cancer screening. Most researches have been carried out in developed countries where lung cancer incidence and mortality is very high. There is an increasing trend in lung cancer incidence in developing countries attributed to tobacco smoking and various environmental and occupational risk factors. Implementation of lung cancer screening is challenging, so organised lung cancer screening is practically non-existent. There are numerous challenges in implementing such programs ranging from infrastructure, trained human resources, referral algorithm to cost and psychological trauma due to over-diagnosis. Pulmonary tuberculosis and other chest infections are important issues to be addressed while planning for lung cancer screening in developing countries. Burden of these diseases is very high and can lead to over-diagnosis in view of cut off of lung nodule size in various studies. Assessment of high risk cases for lung cancer is difficult as various forms of smoking make quantification non-uniform and difficult. Lung cancer screening targets only high risk population unlike screening programs for other cancers where entire population is targeted. There is a need of lung cancer screening for high risk cases as it saves life. Tobacco control and smoking cessation remain the most important long term intervention to decrease morbidity and mortality from lung cancer in developing countries. There is no sufficient evidence supporting the introduction of population-based screening for lung cancer in public health services.

Bronchoscopy: Diagnostic and Therapeutic for Non-Small Cell Lung Cancer

The bronchoscope has gone through much advancement from its origin as a thin metal tube. It has become a highly sophisticated tool for clinicians. Both rigid and the flexible bronchoscopes are invaluable in the diagnosis and treatment of non-small cell lung cancer. Treatment of this disease process hinges on accurate diagnosis and lymph node staging. Technologies, such as endobronchial ultrasound, navigational bronchoscopy, and autofluorescence, have improved efficacy of endobronchial diagnosis and sample collection. If a patient is not a candidate for surgery and has a complication from a centrally located mass, the bronchoscope has been used to deliver palliative therapies.

Autofluorescence and white light imaging-guided endoscopic Raman and diffuse reflectance spectroscopy for in vivo nasopharyngeal cancer detection

Nasopharyngeal cancer (NPC) is an endemic with high incidence in Southern China and Southeast Asia countries. Screening for NPC under conventional white light imaging (WLI) nasopharyngoscope examination remains a great clinical challenge due to its poor sensitivity. Here, we developed an integrated 4-modality endoscopy system combining WLI, autofluorescence imaging (AFI), diffuse reflectance spectroscopy and Raman spectroscopy technologies for in vivo endoscopic cancer detection for the first time. A pilot clinical test of the system for NPC detection was conducted, in which 283 in vivo Raman and diffuse reflectance spectral data sets from 30 NPC patients and 30 healthy subjects were acquired under the guidance of AFI and WLI. Both high diagnostic sensitivity (98.6%) and high specificity (95.1%) for differentiating cancer from normal tissue sites were achieved using this system combined with principal component analysis-linear discriminant analysis diagnostic algorithm, demonstrating great potential for improving real-time, in vivo diagnosis of NPC at endoscopy.

Model-based quantitative optical biopsy in multilayer in vitro soft tissue models for whole field assessment of nonmelanoma skin cancer

Optical techniques such as fluorescence and diffuse reflectance spectroscopy are proven to have the potential to provide tissue discrimination during the development of malignancies and hence treated as potential tools for noninvasive optical biopsy in clinical diagnostics. Quantitative optical biopsy is challenging and hence the majority of the existing strategies are based on a qualitative assessment of the concerned tissue. Light-tissue interaction models as well as precise optical phantoms can greatly help in the former and here we present a pilot study to assess the optical properties of a multilayer tissue-specific optical phantom with the help of a database generated using multilayer-Monte Carlo (MCML) models. A set of optical models mimicking the properties of actual and diseased conditions of tissues associated with nonmelanoma skin cancer (NMSC) were devised and MCML simulations of fluorescence and diffuse reflectance were performed on these models to generate the spectral signature of identified biomarkers of NMSC such as hemoglobin, flavin adenine dinucleotide, and collagen. A model library was generated and with the extracted features from modeled spectra, classification of normal and NMSC conditions were tested using the [Formula: see text]-nearest neighbor (KNN) classifier. Using an in-house assembled scan-based automated bimodal spectral imaging system with reflectance and fluorescence modalities of operation, a layered, thin, tissue equivalent phantom, fabricated with controlled optical properties mimicking normal and NMSC conditions were tested. The spectral signatures corresponding to the NMSC biomarkers were acquired from this phantom and extracted features from the spectra were tested using the KNN classifier and classification accuracy of 100% was achieved. For further quantitative analysis, the experimental and simulated spectra were compared with respect to the light intensity at the emission peak or absorption dips, spectral line width, and average intensity over a range of wavelength of interest and observed to be analogous within specified and systematic error limits. This methodology is expected to give a better quantitative approach for estimation of tissue properties by correlating the experimental and simulated data.

Case series about ex vivo identification of squamous cell carcinomas by laser-induced autofluorescence and Fourier transform infrared spectroscopy

An ex vivo case series aimed at identification of normal laryngeal tissue from laryngeal epidermoid squamous keratinized carcinoma by measuring laser-induced autofluorescence (LIAF) and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectra is presented. The case series results were obtained for paired samples extracted from three patients (exclusion: macroscopic changes of normal vocal cord observed during surgery; surgical intervention on vocal cord, treated only with chemotherapy or radiotherapy for carcinoma; inclusion: men, aged 57-68, non-smokers). For LIAF analysis, a 375-nm picosecond pulsed laser diode with 31 MHz pulse repetition rate, 100 ps full-time width at half-maximum, and average power 0.49 μW was used. LIAF and FTIR-ATR spectra show noticeable differences between normal and malignant tissues. LIAF spectra differed in shape of emitted band, peak position, and band relative intensity of the two kinds of samples, evidencing hypsochromic shift and mean fluorescence intensity decrease of (75.42 ± 3)% in malignant tissue with respect to the normal one. The lack of 1745 cm^-1 band in FTIR-ATR spectra for malignant tissues could be considered an important indicative of the presence of this kind of tissue; moreover, it resulted a greater contribution of lipids and proteins in normal tissue and of collagen in malignant tissue. Penetration depth of the evanescent wave was about 2 μm at an angle of 42°. The two spectroscopic methods are complementary, are applicable for real-time measurements, and may enhance cancer detection and diagnostics. Results presented in this study evidence the potential of the two methods for future in vivo studies.

Real-time endoscopic Raman spectroscopy for in vivo early lung cancer detection

Currently the most sensitive method for localizing lung cancers in central airways is autofluorescence bronchoscopy (AFB) in combination with white light bronchoscopy (WLB). The diagnostic accuracy of WLB + AFB for high grade dysplasia (HGD) and carcinoma in situ is variable depending on physician's experience. When WLB + AFB are operated at high diagnostic sensitivity, the associated diagnostic specificity is low. Raman spectroscopy probes molecular vibrations and gives highly specific, fingerprint-like spectral features and has high accuracy for tissue pathology classification. In this study we present the use of a real-time endoscopy Raman spectroscopy system to improve the specificity. A spectrum is acquired within 1 second and clinical data are obtained from 280 tissue sites (72 HGDs/malignant lesions, 208 benign lesions/normal sites) in 80 patients. Using multivariate analyses and waveband selection methods on the Raman spectra, we have demonstrated that HGD and malignant lung lesions can be detected with high sensitivity (90%) and good specificity (65%).

The role of bronchoscopy in the diagnosis of early lung cancer: a review

Lung cancer is the leading cause of cancer-related deaths worldwide with an overall 5-year survival rate of 17% after diagnoses. Indeed many patients tend to have a very poor prognosis, due to being diagnosed at an advanced stage. Conversely patients who are diagnosed at an early stage have a 5-year survival >70%, indicating that early detection of lung cancer is crucial to improve survival. Although flexible bronchoscopy is a relatively non-invasive procedure for patients suspected of having lung cancer, only 29% of carcinoma in situ (CIS) and 69% of microinvasive tumors were detectable using white light bronchoscopy (WLB) alone. As a result, in the past two decades, new bronchoscopic techniques have been developed to increase the yield and diagnostic accuracy, such as autofluorescence bronchoscopy (AFB), narrow band imaging (NBI) and high magnification bronchovideoscopy (HMB). However, due to the low specificity and the limitation to detect only proximal bronchial tree, new probe-based technologies have been introduced: radial endobronchial ultrasound (R-EBUS), optical coherence tomography (OCT), confocal laser endomicroscopy (CLE) and laser Raman spectroscopy (LRS). To date, although tissue biopsy remains the gold standard for diagnosing malignant/premalignant airway disease and some techniques are still investigational, bronchoscopic technologies can be considered the safest and most accurate tools to evaluate both central and distal airway mucosa.

White light, autofluorescence and narrow-band imaging bronchoscopy for diagnosing airway pre-cancerous and early cancer lesions: a systematic review and meta-analysis

BACKGROUND

We aimed to summarize the diagnostic accuracy of white light bronchoscopy (WLB) and advanced techniques for airway pre-cancerous lesions and early cancer, such as autofluorescence bronchoscopy (AFB), AFB combined with WLB (AFB + WLB) and narrow-band imaging (NBI) bronchoscopy.

METHODS

We searched for eligible studies in seven electronic databases from their date of inception to Mar 20, 2015. In eligible studies, detected lesions should be confirmed by histopathology. We extracted and calculated the 2×2 data based on the pathological criteria of lung tumor, including high-grade lesions from moderate dysplasia (MOD) to invasive carcinoma (INV). Random-effect model was used to pool sensitivity, specificity, diagnostic odds ratio (DOR) and the area under the receiver-operating characteristic curve (AUC).

RESULTS

In 53 eligible studies (39 WLB, 39 AFB, 17 AFB + WLB, 6 NBI), diagnostic performance for high-grade lesions was analyzed based on twelve studies (10 WLB, 7 AFB, 7 AFB + WLB, 1 NBI), involving with totally 2,880 patients and 8,830 biopsy specimens. The sensitivity, specificity, DOR and AUC of WLB were 51% (95% CI, 34-68%), 86% (95% CI, 73-84%), 6 (95% CI, 3-13) and 77% (95% CI, 73-81%). Those of AFB and AFB + WLB were 93% (95% CI, 77-98%) and 86% (95% CI, 75-97%), 52% (95% CI, 37-67%) and 71% (95% CI, 56-87%), 15 (95% CI, 4-57) and 16 (95% CI, 6-41), and 76% (95% CI, 72-79%) and 82% (95% CI, 78-85%), respectively. NBI presented 100% sensitivity and 43% specificity.

CONCLUSIONS

With higher sensitivity, advanced bronchoscopy could be valuable to avoid missed diagnosis. Combining strategy of AFB and WLB may contribute preferable diagnosis rather than their alone use for high-grade lesions. Studies of NBI warrants further investigation for precancerous lesions.

A Randomized Phase IIb Trial of myo-Inositol in Smokers with Bronchial Dysplasia

Previous preclinical studies and a phase I clinical trial suggested that myo-inositol may be a safe and effective lung cancer chemopreventive agent. We conducted a randomized, double blind, placebo-controlled phase IIb study to determine the chemopreventive effects of myo-inositol in smokers with bronchial dysplasia. Smokers with ≥1 site of dysplasia identified by autofluorescence bronchoscopy-directed biopsy were randomly assigned to receive oral placebo or myo-inositol, 9 g once a day for 2 weeks, and then twice a day for 6 months. The primary endpoint was change in dysplasia rate after 6 months of intervention on a per-participant basis. Other trial endpoints reported herein include Ki-67 labeling index, blood and bronchoalveolar lavage fluid (BAL) levels of proinflammatory, oxidant/antioxidant biomarkers, and an airway epithelial gene expression signature for PI3K activity. Seventy-four (n = 38 myo-inositol and n = 36 placebo) participants with a baseline and 6-month bronchoscopy were included in all efficacy analyses. The complete response and the progressive disease rates were 26.3% versus 13.9% and 47.4% versus 33.3%, respectively, in the myo-inositol and placebo arms (P = 0.76). Compared with placebo, myo-inositol intervention significantly reduced IL6 levels in BAL over 6 months (P = 0.03). Among those with a complete response in the myo-inositol arm, there was a significant decrease in a gene expression signature reflective of PI3K activation within the cytologically normal bronchial airway epithelium (P = 0.002). The heterogeneous response to myo-inositol suggests a targeted therapy approach based on molecular alterations is needed in future clinical trials to determine the efficacy of myo-inositol as a chemopreventive agent. Cancer Prev Res; 9(12); 906-14. ©2016 AACR.

Endoscopic high-resolution autofluorescence imaging and OCT of pulmonary vascular networks

High-resolution imaging from within airways may allow new methods for studying lung disease. In this work, we report an endoscopic imaging system capable of high-resolution autofluorescence imaging (AFI) and optical coherence tomography (OCT) in peripheral airways using a 0.9 mm diameter double-clad fiber (DCF) catheter. In this system, AFI excitation light is coupled into the core of the DCF, enabling tightly focused excitation light while maintaining efficient collection of autofluorescence emission through the large diameter inner cladding of the DCF. We demonstrate the ability of this imaging system to visualize pulmonary vasculature as small as 12 μm in vivo.

Accuracy of autofluorescence in diagnosing oral squamous cell carcinoma and oral potentially malignant disorders: a comparative study with aero-digestive lesions

Presently, various studies had investigated the accuracy of autofluorescence in diagnosing oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD) with diverse conclusions. This study aimed to assess its accuracy for OSCC and OPMD and to investigate its applicability in general dental practice. After a comprehensive literature search, a meta-analysis was conducted to calculate the pooled diagnostic indexes of autofluorescence for premalignant lesions (PML) and malignant lesions (ML) of the oral cavity, lung, esophagus, stomach and colorectum and to compute indexes regarding the detection of OSCC aided by algorithms. Besides, a u test was performed. Twenty-four studies detecting OSCC and OPMD in 2761 lesions were included. This demonstrated that the overall accuracy of autofluorescence for OSCC and OPMD was superior to PML and ML of the lung, esophagus and stomach, slightly inferior to the colorectum. Additionally, the sensitivity and specificity for OSCC and OPMD were 0.89 and 0.8, respectively. Furthermore, the specificity could be remarkably improved by additional algorithms. With relatively high accuracy, autofluorescence could be potentially applied as an adjunct for early diagnosis of OSCC and OPMD. Moreover, approaches such as algorithms could enhance its specificity to ensure its efficacy in primary care.

Detection of Pre-Invasive Lung Cancer: Technical Aspects of the LIFE Project

Lung cancer is the leading cause of cancer deaths in both men and women in the United States. The LIFE (Light Induced Fluorescence Endoscopy) Project was initiated at the University of North Carolina Medical Center in November, 1999, for the dual purposes of (1) detecting pre-invasive lung cancer in high-risk patients and (2) studying the molecular biology of pre-invasive lesions of the bronchus for possible development of molecular biomarkers. Of the 47 patients enrolled, all were current or former tobacco smokers, except for 1. Fluorescence endoscopy was utilized, in addition to white light bronchoscopy, to increase the detection of intraepithelial lesions. Adjacent biopsies were submitted for permanent and frozen sections, respectively, from four predetermined sites as well as from any abnormal areas. The snap-frozen specimens were cryostat sectioned, and the mucosal epithelial cells laser capture microdissected for DNA analysis. The great majority of specimens yielded sufficiently abundant and intact DNA to accomplish the molecular objectives. Histologic concordance of adjacent permanent and frozen sections was equivalent to the concordance of adjacent permanent sections, suggesting that frozen section diagnosis was adequate for the research purpose of correlating histology with molecular analysis.

Low Prevalence of High-Grade Lesions Detected With Autofluorescence Bronchoscopy in the Setting of Lung Cancer Screening in the Pan-Canadian Lung Cancer Screening Study

BACKGROUND

Lung cancer screening with low-dose CT (LDCT) scan has been demonstrated to reduce lung cancer mortality. Preliminary reports suggested that up to 20% of lung cancers may be CT scan occult but detectable by autofluorescence bronchoscopy (AFB). We evaluated the prevalence of CT scan occult, invasive, and high-grade preinvasive lesions in high-risk participants undergoing screening for lung cancer.

METHODS

The first 1,300 participants from seven centers in the Pan-Canadian Early Detection of Lung Cancer Study who had ≥ 2% lung cancer risk over 5 years were invited to have an AFB in addition to a LDCT scan. We determined the prevalence of CT scan and AFB abnormalities and analyzed the association between selected predictor variables and preinvasive lesions plus invasive cancer.

RESULTS

A total of 776 endobronchial biopsies were performed in 333 of 1,300 (25.6%) participants. Dysplastic or higher-grade lesions were detected in 5.3% of the participants (n = 68; mild dysplasia: n = 36, moderate dysplasia: n = 25, severe dysplasia: n = 3, carcinoma in situ [CIS]: n = 1, and carcinoma: n = 4). Only one typical carcinoid tumor and one CIS lesion were detected by AFB alone, for a rate of CT scan occult cancer of 0.15% (95% CI, 0.0%-0.6%). Fifty-six prevalence lung cancers were detected by LDCT scan (4.3%). The only independent risk factors for finding of dysplasia or CIS on AFB were smoking duration (OR, 1.05; 95% CI, 1.02-1.07) and FEV₁ percent predicted (OR, 0.99; 95% CI, 0.98-0.99).

CONCLUSIONS

The addition of AFB to LDCT scan in a high lung cancer risk cohort detected too few CT occult cancers (0.15%) to justify its incorporation into a lung cancer screening program.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00751660; URL: www.clinicaltrials.gov.

Topical MMP beacon enabled fluorescence-guided resection of oral carcinoma

Each year almost 300,000 individuals worldwide are diagnosed with oral cancer, more than 90% of these being oral carcinoma [N. Engl. J. Med.328, 1841993]. Surgical resection is the standard of care, but accurate delineation of the tumor boundaries is challenging, resulting in either under-resection with risk of local recurrence or over-resection with increased functional loss and negative impact on quality of life. This study evaluates, in two pre-clinical in vivo tumor models, the potential of fluorescence-guided resection using molecular beacons activated by metalloproteinases, which are frequently upregulated in human oral cancer. In both models there was rapid (<15 min) beacon activation upon local application, allowing clear fluoresecence imaging in vivo and confirmed by ex vivo fluorescence microscopy and HPLC, with minimal activation in normal oral tissues. Although the tissue penetration was limited using topical application, these findings support further development of this approach towards translation to first-in-human trials.

Persistence of Bronchial Dysplasia Is Associated with Development of Invasive Squamous Cell Carcinoma

Bronchial dysplasia (BD), a presumed precursor of pulmonary squamous cell carcinoma (SCC), rarely progresses to invasive cancer. A high-risk cohort at the University of Colorado provided an opportunity to directly sample airway epithelium at mapped sites on successive bronchoscopies. We have hypothesized that persistent dysplastic lesions showing a similar or higher level of dysplasia on follow-up biopsy, are associated with increased risk for the development of SCC. Endoscopic biopsies from 188 high-risk subjects were histologically classified according to the current WHO classification for BD using a numeric histology score ranging from 1 to 8 representing normal bronchial mucosa through invasive lung cancer. Differences in follow-up histology scores were compared between sites classified by clinical, histologic, and immunohistochemical variables. Subjects with a higher frequency of sites that persist or progress to high-grade dysplasia (≥37.5% persist/progress, N = 35 versus <37.5% persist/progress, N = 114) show a significant association with development of incident invasive SCC (adjusted HR, 7.84; 95% confidence interval, 1.56-39.39), and those with incident lung SCC have adjusted mean follow-up histology scores 1.55 U higher than in subjects without lung cancer. Current smoking, elevated Ki67 growth fraction, histologic features of angiogenic squamous dysplasia (ASD) and higher histology score in baseline biopsies are significantly associated with increased follow-up histology scores. These results show that persistent BD is associated with the development of invasive SCC. Furthermore, increased expression of Ki67, the presence of angiogenic change and degree of baseline atypia are associated with persistence of BD.

A Phase I Study of Light Dose for Photodynamic Therapy Using 2-[1-Hexyloxyethyl]-2 Devinyl Pyropheophorbide-a for the Treatment of Non-Small Cell Carcinoma In Situ or Non-Small Cell Microinvasive Bronchogenic Carcinoma: A Dose Ranging Study

INTRODUCTION

We report a phase I trial of photodynamic therapy (PDT) of carcinoma in situ (CIS) and microinvasive cancer (MIC) of the central airways with the photosensitizer (PS) 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH). HPPH has the advantage of minimal general phototoxicity over the commonly used photosensitizer porfimer sodium (Photofrin; Pinnacle Biologics, Chicago, IL).

METHODS

The objectives of this study were (1) to determine the maximally tolerated light dose at a fixed photosensitizer dose and (2) to gain initial insight into the effectiveness of this treatment approach. Seventeen patients with 21 CIS/MIC lesions were treated with HPPH with light dose escalation starting from 75 J/cm2 and increasing to 85, 95,125, and 150 J/cm2 respectively. Follow-up bronchoscopy for response assessment was performed at 1 and 6 months, respectively.

RESULTS

The rate of pathological complete response (CR) was 82.4% (14 of 17 evaluable lesions; 14 patients) at 1 month and 72.7% (8/11 evaluable lesions; 8 patients) at 6 months. Only four patients developed mild skin erythema. One of the three patients in the 150 J/cm2 light dose group experienced a serious adverse event. This patient had respiratory distress caused by mucus plugging, which precipitated cardiac ischemia. Two additional patients treated subsequently at this light dose had no adverse events. The sixth patient in this dose group was not recruited and the study was terminated because of delays in HPPH supply. However, given the observed serious adverse event, it is recommended that the light dose does not exceed 125 J/cm2.

CONCLUSIONS

PDT with HPPH can be safely used for the treatment of CIS/MIC of the airways, with potential effectiveness comparable to that reported for porfimer sodium in earlier studies.

Autofluorescence (safe) bronchoscopy and p21/ki-67 immunostaining related to carcinogenesis

Archival biopsy materials from 20 randomly selected asymptomatic volunteers from the Czech uranium miners (CZ UM) risk group (n=98) were examined for p21 and ki-67 immunostatning. There were 16 areas with normal respiratory epithelium and 22 areas with bronchial intra-epithelial neoplasia (IEN). Normal and IEN areas were identified by autofluorescence (System Autofluorescence Endoscopy, SAFE-1000) and monitored during 1998-2002. The majority of specimens from areas with normal autofluorescence intensity with ciliated columnar bronchial epithelium showed strong predominantly cytoplasmic p21 positivity. The SAFE monitoring divided areas of decreased autofluorescence intensity with early stage IEN lesions into two groups. Persistent lesions (P)-showing a spectrum of p21 cytoplasmic staining ranging from negative or isolated negativity to weak or moderate positivity combined with higher proliferative capacity proved by ki-67 nuclear staining. Disappearing lesions (D)-showing strong cytoplasmic p21 positivity and negative ki-67 staining. The IEN lesions were classified into three groups based on p21/ki-67 immunostaining: proliferative lesions at risk (R) with low or without p21 plasma immunostaining combined with high ki-67 nuclear reactivity; ambiguous lesions (A) including cases combining strong p21 cytoplasmic positivity with high ki-67 nuclear reactivity or p21 cytoplasmic negativity with ki-67 negativity staining patterns; the quiescent lesion group (Q) was characterized by strong p21 cytoplasmic positivity and negative ki-67 immunostaining.

Lung cancer screening: history, current perspectives, and future directions

Lung cancer has remained the leading cause of death worldwide among all cancers. The dismal 5-year survival rate of 16% is in part due to the lack of symptoms during early stages and lack of an effective screening test until recently. Chest X-ray and sputum cytology were studied extensively as potential screening tests for lung cancer and were conclusively proven to be of no value. Subsequently, a number of studies compared computed tomography (CT) with the chest X-ray. These studies did identify lung cancer in earlier stages. However, they were not designed to prove a reduction in mortality. Later trials have focused on low-dose CT (LDCT) as a screening tool. The largest US trial - the National Lung Screening Trial (NLST) - enrolled approximately 54,000 patients and revealed a 20% reduction in mortality. While a role for LDCT in lung cancer screening has been established, the issues of high false positive rates, radiation risk, and cost effectiveness still need to be addressed. The guidelines of the international organizations that now include LDCT in lung cancer screening are reviewed. Other methods that may improve earlier detection such as positron emission tomography, autofluorescence bronchoscopy, and molecular biomarkers are also discussed.

Endoscopic Doppler optical coherence tomography and autofluorescence imaging of peripheral pulmonary nodules and vasculature

We present the first endoscopic Doppler optical coherence tomography and co-registered autofluorescence imaging (DOCT-AFI) of peripheral pulmonary nodules and vascular networks in vivo using a small 0.9 mm diameter catheter. Using exemplary images from volumetric data sets collected from 31 patients during flexible bronchoscopy, we demonstrate how DOCT and AFI offer complementary information that may increase the ability to locate and characterize pulmonary nodules. AFI offers a sensitive visual presentation for the rapid identification of suspicious airway sites, while co-registered OCT provides detailed structural information to assess the airway morphology. We demonstrate the ability of AFI to visualize vascular networks in vivo and validate this finding using Doppler and structural OCT. Given the advantages of higher resolution, smaller probe size, and ability to visualize vasculature, DOCT-AFI has the potential to increase diagnostic accuracy and minimize bleeding to guide biopsy of pulmonary nodules compared to radial endobronchial ultrasound, the current standard of care.

Real-time in vivo cancer diagnosis using Raman spectroscopy

Raman spectroscopy has becoming a practical tool for rapid in vivo tissue diagnosis. This paper provides an overview on the latest development of real-time in vivo Raman systems for cancer detection. Instrumentation, data handling, as well as oncology applications of Raman techniques were covered. Optic fiber probes designs for Raman spectroscopy were discussed. Spectral data pre-processing, feature extraction, and classification between normal/benign and malignant tissues were surveyed. Applications of Raman techniques for clinical diagnosis for different types of cancers, including skin cancer, lung cancer, stomach cancer, oesophageal cancer, colorectal cancer, cervical cancer, and breast cancer, were summarized. Schematic of a real-time Raman spectrometer for skin cancer detection. Without correction, the image captured on CCD camera for a straight entrance slit has a curvature. By arranging the optic fiber array in reverse orientation, the curvature could be effectively corrected.

Biomarkers for screening of lung cancer and pre-neoplastic lesions in a high risk Chilean population

BACKGROUND

The mortality of lung cancer (LC), increases each year in the world, in spite of any advances, in development of new drugs to advance stages of LC. The high incidence of LC has been associated with smoking habit, genetic diversity and environmental pollution. Antofagasta region has been reported to have the highest LC mortality rate in Chile and its inhabitants were exposed to arsenic in their drinking water in concentrations as high as 870 μg/L. Non-invasive techniques such as biomarkers (Automatic Quantitative Cytometry: AQC and DR70) and Auto Fluorescence Bronchoscopy (AFB) might be potentially useful as a supplementary diagnostic approach and early detection. Early detection is one of the most important factors to intervene and prevent cancer progression in LC. This is a work of an ongoing prospective bimodality cancer surveillance study in high risk LC volunteers. Enrolment was done in subjects from Antofagasta and Metropolitan regions. In addition, we enrolled subjects who were suspected of having lung cancer. AQC, DR70 and AFB were used as tools in the detection of pre-neoplastic (PNL) and neoplastic lesions (NL).

RESULTS

Half of the samples, classified as suspicious by AFB, were confirmed as metaplasia or dysplasia by histopathology. For LC, DR70 showed a higher sensitivity (95.8%) and specificity (91.9%) than AQC. However, for PNL AQC showed a higher sensitivity (91.9%) than DR70 (27.3%), although both with low PPV values. As a pre screener, both biomarkers might be employed as complementary tools to detect LC, especially as serially combined tests, with a sensitivity of 60% and a PPV of 65.2%. Additionally, the use of parallel combined tests might support the detection of PNL (sensitivity 91.2%; PPV 49.1%).

CONCLUSION

This work adds information on cellular and molecular biomarkers to complement imaging techniques for early detection of LC in Latin America that might contribute to formulate policies concerning screening of LC. Supported by INNOVA-CORFO, Chile.

A high-efficiency fiber-based imaging system for co-registered autofluorescence and optical coherence tomography

We present a power-efficient fiber-based imaging system capable of co-registered autofluorescence imaging and optical coherence tomography (AF/OCT). The system employs a custom fiber optic rotary joint (FORJ) with an embedded dichroic mirror to efficiently combine the OCT and AF pathways. This three-port wavelength multiplexing FORJ setup has a throughput of more than 83% for collected AF emission, significantly more efficient compared to previously reported fiber-based methods. A custom 900 µm diameter catheter ‒ consisting of a rotating lens assembly, double-clad fiber (DCF), and torque cable in a stationary plastic tube ‒ was fabricated to allow AF/OCT imaging of small airways in vivo. We demonstrate the performance of this system ex vivo in resected porcine airway specimens and in vivo in human on fingers, in the oral cavity, and in peripheral airways.

Photodynamic therapy (PDT) for lung cancer: the Yorkshire Laser Centre experience

BACKGROUND

The Yorkshire Laser Centre team have been engaged in photodynamic therapy (PDT) since 1990. In this article we review our experience in bronchoscopic PDT for lung cancer and outline our current indications and results.

METHODS

160 patients in 2 groups entered into a prospective study: Group A (N=144) were symptomatic with advanced inoperable disease and with presence of >50% bronchial obstruction. Group E (N=16) with early stage cancer and presence of superficial lesion confined to bronchial tree. All patients had standard investigation and work-up bronchoscopy and biopsy confirmation of cancer by cyto-histology. PDT method was intravenous administration of 2mg/kg BW of Photofrin (Porfimer Sodium) followed by bronchoscopic illumination of 630nm laser light.

RESULTS

There was no treatment-related mortality. Nine patients (5.6%) presented with skin photosensitivity reaction and another eight with respiratory complication. Group A: Symptom relief was achieved in all. This was matched by significant improvement in bronchial opening (58.1%). Survival was 9.6 months (mean) and 5 months (median), respectively. This was greater in patients with better performance status and lower stage of disease. Group E: Every patient had a complete response to treatment, some after two treatments. Survival in this group was 75.4 months (mean) and 69 months (median).

CONCLUSIONS

Bronchoscopic PDT is indicated in both advanced and early stage lung cancer. In the former it provides symptomatic relief in all and survival benefit in some; in the latter it achieves long survival and potential cure.

Cell migration leads to spatially distinct but clonally related airway cancer precursors

BACKGROUND

Squamous cell carcinoma of the lung is a common cancer with 95% mortality at 5 years. These cancers arise from preinvasive lesions, which have a natural history of development progressing through increasing severity of dysplasia to carcinoma in situ (CIS), and in some cases, ending in transformation to invasive carcinoma. Synchronous preinvasive lesions identified at autopsy have been previously shown to be clonally related.

METHODS

Using autofluorescence bronchoscopy that allows visual observation of preinvasive lesions within the upper airways, together with molecular profiling of biopsies using gene sequencing and loss-of-heterozygosity analysis from both preinvasive lesions and from intervening normal tissue, we have monitored individual lesions longitudinally and documented their visual, histological and molecular relationship.

RESULTS

We demonstrate that rather than forming a contiguous field of abnormal tissue, clonal CIS lesions can develop at multiple anatomically discrete sites over time. Further, we demonstrate that patients with CIS in the trachea have invariably had previous lesions that have migrated proximally, and in one case, into the other lung over a period of 12 years.

CONCLUSIONS

Molecular information from these unique biopsies provides for the first time evidence that field cancerisation of the upper airways can occur through cell migration rather than via local contiguous cellular expansion as previously thought. Our findings urge a clinical strategy of ablating high-grade premalignant airway lesions with subsequent attentive surveillance for recurrence in the bronchial tree.

Coregistered autofluorescence-optical coherence tomography imaging of human lung sections

Autofluorescence (AF) imaging can provide valuable information about the structural and metabolic state of tissue that can be useful for elucidating physiological and pathological processes. Optical coherence tomography (OCT) provides high resolution detailed information about tissue morphology. We present coregistered AF-OCT imaging of human lung sections. Adjacent hematoxylin and eosin stained histological sections are used to identify tissue structures observed in the OCT images. Segmentation of these structures in the OCT images allowed determination of relative AF intensities of human lung components. Since the AF imaging was performed on tissue sections perpendicular to the airway axis, the results show the AF signal originating from the airway wall components free from the effects of scattering and absorption by overlying layers as is the case during endoscopic imaging. Cartilage and dense connective tissue (DCT) are found to be the dominant fluorescing components with the average cartilage AF intensity about four times greater than that of DCT. The epithelium, lamina propria, and loose connective tissue near basement membrane generate an order of magnitude smaller AF signal than the cartilage fluorescence.

Thin-film tunable filters for hyperspectral fluorescence microscopy

Hyperspectral imaging is a powerful tool that acquires data from many spectral bands, forming a contiguous spectrum. Hyperspectral imaging was originally developed for remote sensing applications; however, hyperspectral techniques have since been applied to biological fluorescence imaging applications, such as fluorescence microscopy and small animal fluorescence imaging. The spectral filtering method largely determines the sensitivity and specificity of any hyperspectral imaging system. There are several types of spectral filtering hardware available for microscopy systems, most commonly acousto-optic tunable filters (AOTFs) and liquid crystal tunable filters (LCTFs). These filtering technologies have advantages and disadvantages. Here, we present a novel tunable filter for hyperspectral imaging-the thin-film tunable filter (TFTF). The TFTF presents several advantages over AOTFs and LCTFs, most notably, a high percentage transmission and a high out-of-band optical density (OD). We present a comparison of a TFTF-based hyperspectral microscopy system and a commercially available AOTF-based system. We have characterized the light transmission, wavelength calibration, and OD of both systems, and have then evaluated the capability of each system for discriminating between green fluorescent protein and highly autofluorescent lung tissue. Our results suggest that TFTFs are an alternative approach for hyperspectral filtering that offers improved transmission and out-of-band blocking. These characteristics make TFTFs well suited for other biomedical imaging devices, such as ophthalmoscopes or endoscopes.

DNA copy number aberrations in endobronchial lesions: a validated predictor for cancer

We recently identified a DNA copy number aberration (CNA)-based classifier, including changes at 3p26.3-p11.1, 3q26.2-29, and 6p25.3-24.3, as a risk predictor for cancer in individuals presenting with endobronchial squamous metaplasia. The current study was set out to validate the prediction accuracy of this classifier in an independent series of endobronchial squamous metaplastic and dysplastic lesions. The study included 36 high-risk subjects who had endobronchial lesions of various histological grades that were identified and biopsied by autofluorescence bronchoscopy and were subjected to arrayCGH in a nested case-control design. Of the 36 patients, 12 had a carcinoma in situ or invasive carcinoma at the same site at follow-up (median 11 months, range 4-24), while 24 controls remained cancer free (78 months, range 21-142). The previously defined CNA-based classifier demonstrated 92% (95% CI 77% to 98%) accuracy for cancer (in situ) prediction. All nine subjects with CNA-based classifier-positive endobronchial lesions at baseline experienced cancer outcome, whereas all 24 controls and 3 cases were classified as being low risk. In conclusion, CNAs prove to be a highly accurate biomarker for assessing the progression risk of endobronchial squamous metaplastic and dysplastic lesions. This classifier could assist in selecting subjects with endobronchial lesions who might benefit from more aggressive therapeutic intervention or surveillance.

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.

Detection and minimally invasive treatment of early squamous lung cancer

Non-small cell lung cancer (NSCLC) is the most common cause of cancer deaths worldwide. The majority of patents presenting with NSCLC have advanced disease, which precludes curative treatment. Early detection and treatment might result in the identification of more patients with early central lung cancer and improve survival. In addition, the study of early lung cancer improves understanding of lung carcinogenesis and might also reveal new treatment targets for advanced lung cancer. Bronchoscopic investigation of the central airways can reveal both early central lung cancer in situ (stage 0) and other preinvasive lesions such as dysplasia. In the current review we discuss the detection of early squamous lung cancer, the natural history of preinvasive lesions and whether biomarkers can be used to predict progression to cancer. Finally we will review the staging and management of preinvasive lung cancer lesions and the different therapeutic modalities that are available.

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.

Can quantifying free-circulating DNA in plasma be used to identify subjects with high-grade pre-invasive endobronchial lesions?

Increased concentrations of free-circulating plasma DNA (cpDNA) are observed in patients with invasive cancer, including lung cancer. Whether cpDNA levels are elevated in subjects with high-grade pre-invasive lesions of lung squamous cell carcinoma (SqCC) and whether its detection may be of value for identifying subjects at the highest risk of developing lung SqCC is currently unknown. The present study assessed cpDNA levels in subjects with high- and low-grade pre-invasive squamous endobronchial lesions relative to patients with clinically overt lung SqCC and healthy controls using real-time quantitative PCR methodology. The median cpDNA levels of the patients with invasive lung SqCC (n=16) were significantly higher compared with those of the healthy controls (n=16; P<0.01), whereas the cpDNA levels in the subjects with pre-invasive lesions (n=20) did not differ from those of the controls (P=0.29). The cpDNA levels in subjects with high-grade pre-invasive lesions were highly similar to those diagnosed with low-grade pre-invasive lesions (P=0.85). Our data suggest that cpDNA levels are not increased during the pre-invasive stages of lung squamous carcinogenesis.

Randomized phase II trial of sulindac for lung cancer chemoprevention

INTRODUCTION

Sulindac represents a promising candidate agent for lung cancer chemoprevention, but clinical trial data have not been previously reported. We conducted a randomized, phase II chemoprevention trial involving current or former cigarette smokers (≥30 pack-years) utilizing the multi-center, inter-disciplinary infrastructure of the Cancer Prevention Network (CPN).

METHODS

At least 1 bronchial dysplastic lesion identified by fluorescence bronchoscopy was required for randomization. Intervention assignments were sulindac 150mg bid or an identical placebo bid for 6 months. Trial endpoints included changes in histologic grade of dysplasia (per-participant as primary endpoint and per lesion as secondary endpoint), number of dysplastic lesions (per-participant), and Ki67 labeling index.

RESULTS

Slower than anticipated recruitment led to trial closure after randomizing participants (n=31 and n=30 in the sulindac and placebo arms, respectively). Pre- and post-intervention fluorescence bronchoscopy data were available for 53/61 (87%) randomized, eligible participants. The median (range) of dysplastic lesions at baseline was 2 (1-12) in the sulindac arm and 2 (1-7) in the placebo arm. Change in dysplasia was categorized as regression:stable:progression for 15:3:8 (58%:12%:31%) subjects in the sulindac arm and 15:2:10 (56%:7%:37%) subjects in the placebo arm; these distributions were not statistically different (p=0.85). Median Ki67 expression (% cells stained positive) was significantly reduced in both the placebo (30 versus 5; p=0.0005) and sulindac (30 versus 10; p=0.0003) arms, but the difference between arms was not statistically significant (p=0.92).

CONCLUSIONS

Data from this multi-center, phase II squamous cell lung cancer chemoprevention trial do not demonstrate sufficient benefits from sulindac 150mg bid for 6 months to warrant additional phase III testing. Investigation of pathway-focused agents is necessary for lung cancer chemoprevention.

Diagnostic value of autofluorescence bronchoscopy in lung cancer

The role of autofluorescence bronchoscopy (AFB) was primarily investigated in regard to the detection of precancerous lesions of bronchial mucosa. Most of the results confirmed higher sensitivity for the detection of precancerous bronchial lesions, when compared to white light bronchoscopy (WLB) alone. However, it is commonly known that the specificity of AFB remains low. Our findings agree in terms of the detection of premalignant bronchial lesions and early lung cancer, but regarding the detection of synchronous lesions or in the evaluation of lung cancer extension, the specificity of AFB is significantly higher. There is still an ongoing debate in the scientific community whether or not autofluorescence should be used as a screening tool for lung cancer. Results of the majority of published series did not support the general use of AFB as a screening tool for lung cancer; however, these results suggest its use in groups of patients with a high risk of lung cancer. Despite this, some authors still do not recommend its use even in high-risk cases. In recent years, the indications for AFB have been widening and this tool may find its place in routine bronchoscopy. With new indications for AFB, such as the evaluation of tumor extension or follow up after surgical resection, bronchoscopists may make use of this tool more often. A sharp learning curve and a clear distinction between healthy and pathologically altered mucosa make this technology acceptable for inexperienced bronchoscopists. We also investigate new hardware and software improvements in AFB. The addition of backscattered light analysis, ultraviolet spectra, fluorescence-reflectance or dual digital systems could improve the diagnostic yield of this technology.

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.