Detection and localization of early lung cancer by fluorescence bronchoscopy

Initial non-invasive in vivo sensing of the lung using time domain diffuse optics

The in vivo diagnosis and monitoring of pulmonary disorders (caused for example by emphysema, Covid-19, immature lung tissue in infants) could be effectively supported by the non-invasive sensing of the lung through light. With this purpose, we investigated the feasibility of probing the lung by means of time-resolved diffuse optics, leveraging the increased depth (a few centimeters) attained by photons collected after prolonged propagation time (a few nanoseconds). We present an initial study that includes measurements performed on 5 healthy volunteers during a breathing protocol, using a time-resolved broadband diffuse optical spectroscopy system. Those measurements were carried out across the spectral range of 600-1100 nm at a source-detector distance of 3 cm, and at 820 nm over a longer distance (7-9 cm). The preliminary analysis of the in vivo data with a simplified homogeneous model revealed a maximum probing depth of 2.6-3.9 cm, suitable for reaching the lung. Furthermore, we observed variations in signal associated with respiration, particularly evident at long photon propagation times. However, challenges stemming from both intra- and inter-subject variability, along with inconsistencies potentially arising from conflicting scattering and absorption effects on the collected signal, hindered a clear interpretation. Aspects that require further investigation for a more comprehensive understanding are outlined.

Advanced Optical Imaging-Guided Nanotheranostics towards Personalized Cancer Drug Delivery

Nanomedicine involves the use of nanotechnology for clinical applications and holds promise to improve treatments. Recent developments offer new hope for cancer detection, prevention and treatment; however, being a heterogenous disorder, cancer calls for a more targeted treatment approach. Personalized Medicine (PM) aims to revolutionize cancer therapy by matching the most effective treatment to individual patients. Nanotheranostics comprise a combination of therapy and diagnostic imaging incorporated in a nanosystem and are developed to fulfill the promise of PM by helping in the selection of treatments, the objective monitoring of response and the planning of follow-up therapy. Although well-established imaging techniques, such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Positron Emission Tomography (PET) and Single-Photon Emission Computed Tomography (SPECT), are primarily used in the development of theranostics, Optical Imaging (OI) offers some advantages, such as high sensitivity, spatial and temporal resolution and less invasiveness. Additionally, it allows for multiplexing, using multi-color imaging and DNA barcoding, which further aids in the development of personalized treatments. Recent advances have also given rise to techniques permitting better penetration, opening new doors for OI-guided nanotheranostics. In this review, we describe in detail these recent advances that may be used to design and develop efficient and specific nanotheranostics for personalized cancer drug delivery.

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.

Upregulation of glucosamine-phosphate N-acetyltransferase 1 is a promising diagnostic and predictive indicator for poor survival in patients with lung adenocarcinoma

Lung adenocarcinoma, a type of non-small cell lung cancer, is the leading cause of cancer death worldwide. Great efforts have been made to identify the underlying mechanism of adenocarcinoma, especially in relation to oncogenes. The present study by integrating computational analysis with western blotting, aimed to understand the role of the upregulation of glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) in carcinogenesis. In the present study, publicly available gene expression profiles and clinical data were downloaded from The Cancer Genome Atlas to determine the role of GNPNAT1 in lung adenocarcinoma (LUAD). In addition, the association between LUAD susceptibility and GNPNAT1 upregulation were analyzed using Wilcoxon signed-rank test and logistic regression analysis. In LUAD, GNPNAT1 upregulation was significantly associated with disease stage [odds ratio (OR)=2.92, stage III vs. stage I], vital status (dead vs. alive, OR=1.89), cancer status (tumor status vs. tumor-free status, OR=1.85) and N classification (yes vs. no, OR=1.75). Cox regression analysis and the Kaplan-Meier method were utilized to evaluate the association between GNPNAT1 expression and overall survival (OS) time in patients with LUAD. The results demonstrated that patients with increased GNPNAT1 expression levels exhibited a reduced survival rate compared with those with decreased expression levels (P=8.9×10⁻⁵). In addition, Cox regression analysis revealed that GNPNAT1 upregulation was significantly associated with poor OS time [hazard ratio (HR): 1.07; 95% confidence interval (CI): 1.04–1.10; P<0.001]. The gene set enrichment analysis revealed that ‘cell cycle’, ‘oocyte meiosis’, ‘pyrimidine mediated metabolism’, ‘ubiquitin mediated proteolysis’, ‘one carbon pool by folate’, ‘mismatch repair progesterone-mediated oocyte maturation’ and ‘basal transcription factors purine metabolism’ were differentially enriched in the GNPNAT1 high-expression samples compared with GNPNAT1 low-expression samples. The aforementioned pathways are involved in the pathogenesis of LUAD. The findings of the present study suggested that GNPNAT1 upregulation may be considered as a promising diagnostic and prognostic biomarker in patients with LUAD. In addition, the aforementioned pathways may be pivotal pathways perturbed by the abnormal expression of GNPNAT1 in LUAD. The findings of the present study demonstrated the therapeutic value of the regulation of GNPNAT1 in lung adenocarcinoma.

The promises and challenges of early non-small cell lung cancer detection: patient perceptions, low-dose CT screening, bronchoscopy and biomarkers

Lung cancer survival statistics are sobering with survival ranking among the poorest of all cancers despite the addition of targeted therapies and immunotherapies. However, improvements in tools for early detection hold promise. The Nederlands–Leuvens Longkanker Screenings Onderzoek (NELSON) trial recently corroborated the findings from the previous National Lung Screening Trial low‐dose Computerised Tomography (NLST) screening trial in reducing lung cancer mortality. Biomarker research and development is increasing at pace as the molecular life histories of lung cancers become further unravelled. Low‐dose CT screening (LDCT) is effective but targets only those at the highest risk and is burdensome on healthcare. An optimally designed CT screening programme at best will only detect a low proportion of overall lung cancers as only those at very high‐risk meet screening criteria. Biomarkers that help risk stratify suitable patients for LDCT screening, and those that assist in determining which LDCT detected nodules are likely to represent malignant disease are needed. Some biomarkers have been proposed as standalone lung cancer diagnosis tools. Bronchoscopy technology is improving, with better capacity to identify and obtain samples from early lung cancers. Clinicians need to be aware of each early lung cancer detection method’s inherent limitations. We anticipate that the future of early lung cancer diagnosis will involve a synergistic, multimodal approach, combining several early detection methods.

Comparison of autofluorescence and white-light bronchoscopies performed with the Evis Lucera Spectrum for the detection of bronchial cancers: a meta-analysis

Background

Many recent studies have reported that autofluorescence bronchoscopy (AFB) has a superior sensitivity and decreased specificity in the diagnosis of bronchial cancers when compared with white-light bronchoscopy (WLB). We specifically analyzed the diagnostic performances of autofluorescence imaging video bronchoscopy (AFI) performed with the Evis Lucera Spectrum from Olympus, which is a relatively novel approach in detecting and delineating bronchial cancers, and compared it to the older WLB method.

Methods

We searched the PubMed, Embase, Web of Science, and CNKI databases from inception to July 12^th, 2018 for trials in which patients were diagnosed with lung cancer via concurrent or combined use of AFI and WLB. The included studies were required to have a histologic diagnosis as the gold standard comparison, and a sufficient amount of data was extracted to assess the diagnostic capacity. A 2×2 table was constructed, and the area under the receiver-operating characteristic curve (AUC) of AFI and WLB was estimated by using a stochastic model for diagnostic meta-analysis using STATA software.

Results

A total of 10 articles were eligible for the meta analysis, comprising 1,830 patients with complete data included in the analysis. AFI showed a superior sensitivity of 0.92 (95% CI, 0.88-0.95) over WLB's 0.70 (95% CI, 0.58-0.80) with P<0.01, and a comparable specificity of 0.67 (95% CI, 0.51-0.80) compared with WLB's 0.78 (95% CI, 0.68-0.86) with P=0.056. Egger's test P value (0.225) demonstrated that there was no publication bias.

Conclusions

Our research showed that in the evaluation of bronchial cancers, AFI was superior to conventional WLB. With its higher sensitivity, AFI could be valuable for avoiding misdiagnosis.

Sequential screening for lung cancer in a high-risk group: randomised controlled trial: LungSEARCH: a randomised controlled trial of Surveillance using sputum and imaging for the EARly detection of lung Cancer in a High-risk group

BACKGROUND

Low-dose computed tomography (LDCT) screening detects early-stage lung cancer and reduces mortality. We proposed a sequential approach targeted to a high-risk group as a potentially efficient screening strategy.

METHODS

LungSEARCH was a national multicentre randomised trial. Current/ex-smokers with mild/moderate chronic obstructive pulmonary disease (COPD) were allocated (1:1) to have 5 years surveillance or not. Screened participants provided annual sputum samples for cytology and cytometry, and if abnormal were offered annual LDCT and autofluorescence bronchoscopy (AFB). Those with normal sputum provided annual samples. The primary end-point was the percentage of lung cancers diagnosed at stage I/II (nonsmall cell) or limited disease (small cell).

RESULTS

1568 participants were randomised during 2007-2011 from 10 UK centres. 85.2% of those screened provided an adequate baseline sputum sample. There were 42 lung cancers among 785 screened individuals and 36 lung cancers among 783 controls. 54.8% (23 out of 42) of screened individuals versus 45.2% (14 out of 31) of controls with known staging were diagnosed with early-stage disease (one-sided p=0.24). Relative risk was 1.21 (95% CI 0.75-1.95) or 0.82 (95% CI 0.52-1.31) for early-stage or advanced cancers, respectively. Overall sensitivity for sputum (in those randomised to surveillance) was low (40.5%) with a cumulative false-positive rate (FPR) of 32.8%. 55% of cancers had normal sputum results throughout. Among sputum-positive individuals who had AFB, sensitivity was 45.5% and cumulative FPR was 39.5%; the corresponding measures for those who had LDCT were 100% and 16.1%, respectively.

CONCLUSIONS

Our sequential strategy, using sputum cytology/cytometry to select high-risk individuals for AFB and LDCT, did not lead to a clear stage shift and did not improve the efficiency of lung cancer screening.

The diagnostic value of narrow-band imaging for early and invasive lung cancer: a meta-analysis

This study aimed to compare the ability of narrow-band imaging to detect early and invasive lung cancer with that of conventional pathological analysis and white-light bronchoscopy. We searched the PubMed, EMBASE, Sinomed, and China National Knowledge Infrastructure databases for relevant studies. Meta-disc software was used to perform data analysis, meta-regression analysis, sensitivity analysis, and heterogeneity testing, and STATA software was used to determine if publication bias was present, as well as to calculate the relative risks for the sensitivity and specificity of narrow-band imaging vs those of white-light bronchoscopy for the detection of early and invasive lung cancer. A random-effects model was used to assess the diagnostic efficacy of the above modalities in cases in which a high degree of between-study heterogeneity was noted with respect to their diagnostic efficacies. The database search identified six studies including 578 patients. The pooled sensitivity and specificity of narrow-band imaging were 86% (95% confidence interval: 83-88%) and 81% (95% confidence interval: 77-84%), respectively, and the pooled sensitivity and specificity of white-light bronchoscopy were 70% (95% confidence interval: 66-74%) and 66% (95% confidence interval: 62-70%), respectively. The pooled relative risks for the sensitivity and specificity of narrow-band imaging vs the sensitivity and specificity of white-light bronchoscopy for the detection of early and invasive lung cancer were 1.33 (95% confidence interval: 1.07-1.67) and 1.09 (95% confidence interval: 0.84-1.42), respectively, and sensitivity analysis showed that narrow-band imaging exhibited good diagnostic efficacy with respect to detecting early and invasive lung cancer and that the results of the study were stable. Narrow-band imaging was superior to white light bronchoscopy with respect to detecting early and invasive lung cancer; however, the specificities of the two modalities did not differ significantly.

Rapid diagnosis and intraoperative margin assessment of human lung cancer with fluorescence lifetime imaging microscopy

A method of rapidly differentiating lung tumor from healthy tissue is extraordinarily needed for both the diagnosis and the intraoperative margin assessment. We assessed the ability of fluorescence lifetime imaging microscopy (FLIM) for differentiating human lung cancer and normal tissues with the autofluorescence, and also elucidated the mechanism in tissue studies and cell studies. A 15-patient testing group was used to compare FLIM results with traditional histopathology diagnosis. Based on the endogenous fluorescence lifetimes of the testing group, a criterion line was proposed to distinguish normal and cancerous tissues. Then by blinded examined 41 sections from the validation group of other 16 patients, the sensitivity and specificity of FLIM were determined. The cellular metabolism was studied with specific perturbations of oxidative phosphorylation and glycolysis in cell studies. The fluorescence lifetime of cancerous lung tissues is consistently lower than normal tissues, and this is due to the both decrease of reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) lifetimes. A criterion line of lifetime at 1920 ps can be given for differentiating human lung cancer and normal tissues.The sensitivity and specificity of FLIM for lung cancer diagnosis were determined as 92.9% and 92.3%. These findings suggest that NADH and FAD can be used to rapidly diagnose lung cancer. FLIM is a rapid, accurate and highly sensitive technique in the judgment during lung cancer surgery and it can be potential in earlier cancer detection.

Clinical Correlation between Real-Time Endocytoscopy, Confocal Endomicroscopy, and Histopathology in the Central Airways

BACKGROUND

Lung cancer is one of the commonest malignancies with a worldwide incidence of 1.6 million cases each year. Although the main aetiological factor has been identified (cigarette smoking), the progression of lung cancer from early changes such as dysplasia through to cancer is still not fully understood. Furthermore, current research techniques are reliant on obtaining tissue biopsies, a process that alters the natural history of the very process under investigation. Hence, there is a need for developing optical biopsy techniques.

OBJECTIVES

To prospectively evaluate the feasibility of endocytoscopy and confocal endomicroscopy in the detection of malignant and pre-malignant changes in the airways.

METHODS

Findings with endocytoscopy and endomicroscopy were compared with conventional biopsies obtained from the same areas in 25 patients undergoing bronchoscopy for evaluation of endobronchial abnormalities and in 5 healthy control subjects.

RESULTS

Endocytoscopy was technically more difficult, and interpretable images were only obtained in 21 of the patients evaluated, and hence, complete information including histopathological information was available in 21 patients. Endocytoscopy appeared to correlate with the histopathological findings on tissue biopsy, and was able to distinguish normal epithelium from dysplasia and carcinoma. Confocal endomicroscopy was a more reliable technique with adequate visual information obtained in all patients examined but was unable to distinguish between dysplasia and carcinoma.

CONCLUSION

This feasibility study suggests that endocytoscopy may have the potential to fulfil the role of optical biopsy in the evaluation of the pathogenesis of lung cancer.

RGB and HSV quantitative analysis of autofluorescence bronchoscopy used for characterization and identification of bronchopulmonary cancer

Autofluorescence bronchoscopy (AFB) shows good sensitivity in detecting dysplasia and bronchopulmonary cancer. However, the poor specificity of AFB would lead to excessive biopsy. The aim of the study is to establish a more effective quantitative method (optimal identification index and reference value) for characterizing the AFB images within the region of interest and discuss AFB's significance in the diagnosis of central‐type lung cancer. A total of 218 suspected lung cancer patients were enrolled in this study. A quantitative analysis based on color space (red, green, blue[RGB] and HSV system) was conducted and the result was compared with the final diagnosis obtained by the pathology of biopsy. Cases were divided into different groups according to the pathological diagnosis of normal bronchial mucosa, inflammation, low‐grade preinvasive (LGD), high‐grade preinvasive (HGD), and invasive cancer. Quantitative analyses in multi‐color spaces for the lesions showed by AFB images were conducted by software MATLAB. Finally, there is statistical significance among the different groups in some parameter in RGB and HSV system. So, both RGB and HSV quantitative analysis of autofluorescence bronchoscopy are useful to define benign and malignant diseases, which can objectively guide the bronchoscopist in selecting sites for biopsy with good pathologic correlation.

Application of Quantitative Autofluorescence Bronchoscopy Image Analysis Method in Identifying Bronchopulmonary Cancer

Autofluorescence bronchoscopy shows good sensitivity and poor specificity in detecting dysplasia and cancer of the bronchus. Through quantitative analysis on the target area of autofluorescence bronchoscopy image, determine the optimal identification index and reference value for identifying different types of diseases and explore the value of autofluorescence bronchoscopy in diagnosis of lung cancer. Patients with 1 or more preinvasive bronchial lesions were enrolled and followed up by white-light bronchoscope and autofluorescence bronchoscopy. Color space quantitative image analysis was conducted on the lesion shown in the autofluorescence image using MATLAB image measurement software. A retrospective analysis was conducted on 218 cases with 1208 biopsies. One hundred seventy-three cases were diagnosed as positive, which included 151 true-positive cases and 22 false-positive cases. White-light bronchoscope associated with autofluorescence bronchoscopy was able to differentiate between benign and malignant lesion with a high sensitivity, specificity, positive predictive value, and negative predictive value (92.1%, 59.3%, 87.3%, and 71.1%, respectively). Taking 1.485 as the cutoff value of receiver operating characteristic of red-to-green value to differentiate benign and malignant diseases, the diagnostic sensitivity reached 82.3% and the specificity reached 80.5%. U values could differentiate invasive carcinoma and other groups well. Quantitative image analysis method of autofluorescence bronchoscopy provided effective scientific basis for the diagnosis of lung cancer and precancerous lesions.

[Quantization Methodology of Autofluorescence Bronchoscopy Image in the YUV System]

背景与目的

通过对不同病理类型的自荧光气管镜（autofluorescence bronchoscope, AFB）图像目标区域的YUV定量分析，确定区分不同疾病类型的最佳判别指标，探讨AFB在中央型支气管肺癌诊断中的价值。

方法

对研究对象进行白光气管镜+AFB检查，二者在镜下存在异常者行活检。并对荧光图像显示病变部位通过MATLAB图像测量软件进行YUV定量分析。根据正常支气管粘膜、炎症、低级别上皮样瘤变、高级别上皮样瘤变、浸润性癌的病理结果分组。研究各组与YUV值间的关系，所得数据采用SPSS 11.5软件进行统计学处理。

结果

Y值在浸润性癌和LGD组间存在统计学差异（P=0.040），在浸润性癌和炎症组也存在明显统计学差异（P < 0.001）。其他的各组间无统计学差异。U值在浸润性癌和HGD、LGD、炎症、正常支气管粘膜组之间存在统计学差异（P < 0.050），能较好鉴别正常粘膜及恶性病变。V值在浸润性癌和LGD组（P=0.003）、炎症组（P < 0.001）、正常支气管粘膜组（P < 0.001）存在统计学差异，能有效鉴别浸润性癌及良性疾病。V值在正常支气管粘膜组与HGD组（P=0.001）、炎症组（P=0.004）间比较也具有统计学差异。

结论

利用YUV色彩空间系统针对支气管和肺良恶性疾病鉴别有一定临床应用价值，为临床气管镜诊断肺癌及癌前病变提供有效科学依据。

Is it useful to combine sputum cytology and low-dose spiral computed tomography for early detection of lung cancer in formerly asbestos-exposed power industry workers?

Background

Low-dose spiral computed tomography (LDSCT) in comparison to conventional chest X-ray proved to be a highly sensitive method of diagnosing early stage lung cancer. However, centrally located early stage lung tumours remain a diagnostic challenge. We determined the practicability and efficacy of early detection of lung cancer when combining LDSCT and sputum cytology.

Methods

Of a cohort of 4446 formerly asbestos exposed power industry workers, we examined a subgroup of 187 (4.2%) high risk participants for lung cancer at least once with both LDSCT and sputum cytology. After the examination period the participants were followed-up for more than three years.

Results

The examinations resulted in the diagnosis of lung cancer in 12 participants (6.4%). Six were in clinical stage I. We found 10 non-small cell lung carcinomas and one small cell lung carcinoma. Sputum specimens showed suspicious pathological findings in seven cases and in 11 cases the results of LDSCT indicated malignancies. The overall sensitivity and specificity of sputum cytology was 58.0% and 98% with positive (PPV) and negative (NPV) predictive values of 70% and 97%. For LDSCT we calculated the sensitivity and specificity of 92% and 97%. The PPV and NPV were 65% and 99% respectively.

Conclusions

Our results confirmed that in surveillance programmes a combination of sputum cytology and LDSCT is well feasible and accepted by the participants. Sputum examination alone is not effective enough for the detection of lung cancer, especially at early stage. Even in well- defined risk groups highly exposed to asbestos, we cannot recommend the use of combined LDSCT and sputum cytology examinations as long as no survival benefit has been proved for the combination of both methods. For ensuring low rates of false-positive and false-negative results, programme planners must closely cooperate with experienced medical practitioners and pathologists in a well-functioning interdisciplinary network.

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.

Comparison of autofluorescence imaging bronchoscopy and white light bronchoscopy for detection of lung cancers and precancerous lesions

BACKGROUND

The purpose of this paper was to compare the sensitivity, specificity, and overall diagnostic performance of autofluorescence imaging bronchoscopy (AFI) versus white light bronchoscopy (WLB) in the detection of lung cancers and precancerous lesions by meta-analysis.

METHODS

We performed a literature search using the PubMed and EMBASE databases to identify studies published between March 1991 and March 2012. Article selection, quality assessment, and data extraction were then performed. The pooled sensitivity, specificity, diagnostic odds ratio, and area under the curve of the summary receiver operating characteristic for AFI versus WLB were calculated using Stata version 12.0 software.

RESULTS

Six studies were included in the meta-analysis. The pooled sensitivity of AFI and WLB was 0.89 (95% confidence interval [CI] 0.81-0.94) and 0.67 (95% CI 0.46-0.83) and the pooled specificity of AFI and WLB was 0.64 (95% CI 0.37-0.84) and 0.84 (95% CI 0.74-0.91), respectively. The diagnostic odds ratio for AFI and WLB was 14.5 (95% CI 3.76-55.63) and 10.9 (95% CI 3.12-38.21), and the area under the curve for AFI and WLB was 0.89 (95% CI 0.86-0.92) and 0.85 (95% CI 0.81-0.88), respectively. The pooled positive and negative likelihood ratios were 2.5 (95% CI 1.21-4.97) and 0.17 (95% CI 0.08-0.36) for AFI, and the corresponding values for WLB were 4.3 (95% CI 2.13-8.52) and 0.39 (95% CI 0.21-0.73). The pooled positive likelihood ratio for AFI and WLB was not higher than 10, and the pooled negative likelihood ratio for AFI and WLB was not lower than 0.1.

CONCLUSION

The sensitivity of AFI is higher than that of WLB, while the specificity of AFI is lower than that of WLB. The overall diagnostic performance of AFI is slightly better than that of WLB in detecting lung cancers and precancerous lesions. AFI should find its place in routine bronchoscopic examination and may improve the diagnostic outcome on endoscopy.

Advances in molecular imaging: targeted optical contrast agents for cancer diagnostics

Over the last three decades, our understanding of the molecular changes associated with cancer development and progression has advanced greatly. This has led to new cancer therapeutics targeted against specific molecular pathways; such therapies show great promise to reduce mortality, in part by enabling physicians to tailor therapy for patients based on a molecular profile of their tumor. Unfortunately, the tools for definitive cancer diagnosis - light microscopic examination of biopsied tissue stained with nonspecific dyes - remain focused on the analysis of tissue ex vivo. There is an important need for new clinical tools to support the molecular diagnosis of cancer. Optical molecular imaging is emerging as a technique to help meet this need. Targeted, optically active contrast agents can specifically label extra- and intracellular biomarkers of cancer. Optical images can be acquired in real time with high spatial resolution to image-specific molecular targets, while still providing morphologic context. This article reviews recent advances in optical molecular imaging, highlighting the advances in technology required to improve early cancer detection, guide selection of targeted therapy and rapidly evaluate therapeutic efficacy.

Multiphoton microscopy and microspectroscopy for diagnostics of inflammatory and neoplastic lung

Limitations of current medical procedures for detecting early lung cancers inspire the need for new diagnostic imaging modalities for the direct microscopic visualization of lung nodules. Multiphoton microscopy (MPM) provides for subcellular resolution imaging of intrinsic fluorescence from unprocessed tissue with minimal optical attenuation and photodamage. We demonstrate that MPM detects morphological and spectral features of lung tissue and differentiates between normal, inflammatory and neoplastic lung. Ex vivo MPM imaging of intrinsic two-photon excited fluorescence was performed on mouse and canine neoplastic, inflammatory and tumor-free lung sites. Results showed that MPM detected microanatomical differences between tumor-free and neoplastic lung tissue similar to standard histopathology but without the need for tissue processing. Furthermore, inflammatory sites displayed a distinct red-shifted fluorescence compared to neoplasms in both mouse and canine lung, and adenocarcinomas displayed a less pronounced fluorescence emission in the 500 to 550 nm region compared to adenomas in mouse models of lung cancer. These spectral distinctions were also confirmed by two-photon excited fluorescence microspectroscopy. We demonstrate the feasibility of applying MPM imaging of intrinsic fluorescence for the differentiation of lung neoplasms, inflammatory and tumor-free lung, which motivates the application of multiphoton endoscopy for the in situ imaging of lung nodules.

Fluorescence lifetime techniques in medical applications

This article presents an overview of time-resolved (lifetime) fluorescence techniques used in biomedical diagnostics. In particular, we review the development of time-resolved fluorescence spectroscopy (TRFS) and fluorescence lifetime imaging (FLIM) instrumentation and associated methodologies which allow in vivo characterization and diagnosis of biological tissues. Emphasis is placed on the translational research potential of these techniques and on evaluating whether intrinsic fluorescence signals provide useful contrast for the diagnosis of human diseases including cancer (gastrointestinal tract, lung, head and neck, and brain), skin and eye diseases, and atherosclerotic cardiovascular disease.

[Advances in early diagnosis of lung cancer]

Lung cancer is the most common cause of cancer death worldwide. Early diagnosis and early treatment are of great importance. Chest X-ray, spinal CT, bronchoscopy and sputum cytology have long been used as screening or diagnostic modalities for early detection of lung cancer. However, these methods have limitations in sensitivity, specificity or utility in some degree. In recent years, researchers all over the world have done lots of work on finding and identifying biomarkers for the early diagnosis of lung cancer. In this paper, recent developments in this field are reviewed.

Collagen XXIII: a potential biomarker for the detection of primary and recurrent non-small cell lung cancer

BACKGROUND

Collagen XXIII is a transmembrane collagen previously shown to be upregulated in metastatic prostate cancer. The purpose of this study was to determine the protein expression of collagen XXIII in tumor tissues from a variety of cancers and to assess the utility of collagen XXIII as a biomarker for non-small cell lung cancer (NSCLC).

METHODS

A multicancer tissue microarray was used for the immunohistochemical examination of collagen XXIII protein expression in a variety of cancers. Subsequently, collagen XXIII expression was analyzed in three separate cohorts using tissue microarrays with representative tumor and control lung tissues from NSCLC patients. In addition, NSCLC patient urine samples were analyzed for the presence of collagen XXIII through Western blot.

RESULTS

Collagen XXIII was present in tissue samples from a variety of cancers. Within lung cancer tissues, collagen XXIII staining was enriched in NSCLC subtypes. Collagen XXIII was present in 294 of 333 (88%) lung adenocarcinomas and 97 of 133 (73%) squamous cell carcinomas. In urine, collagen XXIII was present in 23 of 29 (79%) NSCLC patient samples but only in 15 of 54 (28%) control samples. High collagen XXIII staining intensity correlated with shorter recurrence-free survival in NSCLC patients.

CONCLUSIONS

We show the capability of collagen XXIII as a tissue and urinary biomarker for NSCLC, in which positivity in tissue or urine significantly correlates with the presence of NSCLC and high staining intensity is a significant recurrence predictor.

IMPACT

Inclusion of collagen XXIII in a tissue- or urine-based cancer biomarker panel could inform NSCLC patient treatment decisions.

Natural history of bronchial preinvasive lesions

Preinvasive bronchial lesions defined as dysplasia and carcinoma in situ (CIS) have been considered as precursors of squamous cell carcinoma of the lung. The risk and rate of progression of preinvasive lesions to invasive squamous cell carcinoma as well as the mechanism of progression or regression are incompletely understood. While the evidence for the multistage, stepwise progression model is weak with relatively few documented lesions that progress through various grades of dysplasia to CIS and then to invasive carcinoma, the concept of field carcinogenesis is strongly supported. The presence of high-grade dysplasia or CIS is a risk marker for lung cancer both in the central airways and peripheral lung. Genetic alterations such as loss of heterozygosity in chromosome 3p or chromosomal aneusomy as well as host factors such as the inflammatory load and levels of anti-inflammatory proteins in the lung influence the progression or regression of preinvasive lesions. CIS is different than severe dysplasia at the molecular level and has different clinical outcome. Molecular analysis of dysplastic lesions that progress to CIS or invasive cancer and rare lesions that progress rapidly from hyperplasia or metaplasia to CIS or invasive cancer will shed light on the key molecular determinants driving development to an invasive phenotype versus those associated with tobacco smoke damage.

Transcriptome profiles of carcinoma-in-situ and invasive non-small cell lung cancer as revealed by SAGE

Background

Non-small cell lung cancer (NSCLC) presents as a progressive disease spanning precancerous, preinvasive, locally invasive, and metastatic lesions. Identification of biological pathways reflective of these progressive stages, and aberrantly expressed genes associated with these pathways, would conceivably enhance therapeutic approaches to this devastating disease.

Methodology/Principal Findings

Through the construction and analysis of SAGE libraries, we have determined transcriptome profiles for preinvasive carcinoma-in-situ (CIS) and invasive squamous cell carcinoma (SCC) of the lung, and compared these with expression profiles generated from both bronchial epithelium, and precancerous metaplastic and dysplastic lesions using Ingenuity Pathway Analysis. Expression of genes associated with epidermal development, and loss of expression of genes associated with mucociliary biology, are predominant features of CIS, largely shared with precancerous lesions. Additionally, expression of genes associated with xenobiotic metabolism/detoxification is a notable feature of CIS, and is largely maintained in invasive cancer. Genes related to tissue fibrosis and acute phase immune response are characteristic of the invasive SCC phenotype. Moreover, the data presented here suggests that tissue remodeling/fibrosis is initiated at the early stages of CIS. Additionally, this study indicates that alteration in copy-number status represents a plausible mechanism for differential gene expression in CIS and invasive SCC.

Conclusions/Significance

This study is the first report of large-scale expression profiling of CIS of the lung. Unbiased expression profiling of these preinvasive and invasive lesions provides a platform for further investigations into the molecular genetic events relevant to early stages of squamous NSCLC development. Additionally, up-regulated genes detected at extreme differences between CIS and invasive cancer may have potential to serve as biomarkers for early detection.

Chemoprevention of lung cancer

Lung cancer is the leading cause of cancer death in the United States, and the majority of diagnoses are made in former smokers. While avoidance of tobacco abuse and smoking cessation clearly will have the greatest impact on lung cancer development, effective chemoprevention could prove to be more effective than treatment of established disease. Chemoprevention is the use of dietary or pharmaceutical agents to reverse or inhibit the carcinogenic process and has been successfully applied to common malignancies other than lung. Despite previous studies in lung cancer chemoprevention failing to identify effective agents, our ability to determine higher risk populations and the understanding of lung tumor and pre-malignant biology continues to advance. Additional biomarkers of risk continue to be investigated and validated. The World Health Organization/International Association for the Study of Lung Cancer classification for lung cancer now recognizes distinct histologic lesions that can be reproducibly graded as precursors of non-small cell lung cancer. For example, carcinogenesis in the bronchial epithelium starts with normal epithelium and progresses through hyperplasia, metaplasia, dysplasia, and carcinoma in situ to invasive squamous cell cancer. Similar precursor lesions exist for adenocarcinoma, and these pre-malignant lesions are targeted by chemopreventive agents in current and future trials. At this time, chemopreventive agents can only be recommended as part of well-designed clinical trials, and multiple trials are currently in progress and additional trials are in the planning stages. This review will discuss the principles of chemoprevention, summarize the completed trials, and discuss ongoing and potential future trials with a focus on targeted pathways.

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.

New imaging approaches for understanding lung cancer response to treatment

The survival rate for lung cancer patients has barely improved over the past 30 years. New evaluation benchmarks for cancer response are needed to test therapy agents in a cost-effective and timely manner. From recent work, it is evident that primary lung cancers are very complex structures containing not only cancerous cells but also fibrotic and inflammatory cells and necrotic tissue. A greater understanding of the three-dimensional structure of primary lung cancer is emerging, allowing for the first time an appreciation of how this biomass is represented in medical imaging data. It is only through a greater understanding of the lung cancer biomass that we can define rational and early-response measures, including specific cellular responses such as cancer cell death or growth inhibition. In doing so, we can define response metrics that will shorten new drug discovery times and reduce costs, allowing for the evaluation of many more agents with therapeutic potential.

In vivo optical coherence tomography imaging of preinvasive bronchial lesions

PURPOSE

Optical coherence tomography (OCT) is an optical imaging method that can visualize cellular and extracellular structures at and below tissue surface. The objective of the study was to determine if OCT could characterize preneoplastic changes in the bronchial epithelium identified by autofluorescence bronchoscopy.

EXPERIMENTAL DESIGN

A 1.5-mm fiberoptic probe was inserted via a bronchoscope into the airways of 138 volunteer heavy smokers participating in a chemoprevention trial and 10 patients with lung cancer to evaluate areas that were found to be normal or abnormal on autofluorescence bronchoscopy. Radial scanning of the airways was done to generate OCT images in real time. Following OCT imaging, the same sites were biopsied for pathologic correlation.

RESULTS

A total of 281 OCT images and the corresponding bronchial biopsies were obtained. The histopathology of these areas includes 145 normal/hyperplasia, 61 metaplasia, 39 mild dysplasia, 10 moderate dysplasia, 6 severe dysplasia, 7 carcinoma in situ, and 13 invasive carcinomas. Quantitative measurement of the epithelial thickness showed that invasive carcinoma was significantly different than carcinoma in situ (P=0.004) and dysplasia was significantly different than metaplasia or hyperplasia (P=0.002). In addition, nuclei of the cells corresponding to histologic results became more discernible in lesions that were moderate dysplasia or worse compared with lower-grade lesions.

CONCLUSION

Preliminary data suggest that autofluorescence bronchoscopy-guided OCT imaging of bronchial lesions is technically feasible. OCT may be a promising nonbiopsy tool for in vivo imaging of preneoplastic bronchial lesions to study their natural history and the effect of chemopreventive intervention.

Integrated CT/bronchoscopy in the central airways: preliminary results

RATIONALE AND OBJECTIVES

Many imaging modalities and methodologies exist for evaluating the pulmonary airways. Individually, each modality provides insight to the state of the airways; however, alone they do not necessarily provide a comprehensive description. The goal of this work is to integrate complementary medical imaging datasets to form a synergistic description of the airways.

MATERIALS AND METHODS

Two digital bronchoscopic techniques were used to evaluate the pulmonary mucosa. A digital color bronchoscopic system was used to detect mucosal color alterations, and a fluorescence detection system was used to assess the microvasculature of the bronchial mucosa. Study participants were also imaged with a multidetector row computed tomographic (MDCT) scanner. Virtual bronchoscopic and image registration techniques were exploited to combine three-dimensional surface renderings, extracted from the MDCT data, together with the two-dimensional digital bronchoscopic images. Validation of the fusion process was performed on a rubber phantom of an adult airway with 4 embedded metal beads.

RESULTS

The fusion of the MDCT extracted airway tree and the digital bronchoscopic datasets were presented for three study participants. In addition, the detected accuracy of the registration method to reliably align the MDCT and bronchoscopic image datasets was determined to be 1.98 mm in the phantom airway model.

CONCLUSION

We have demonstrated that merging of three distinct digital datasets to provide a single synergistic description of the airways is possible. This is a pilot project in the field of eidomics, the process of combining digital image datasets and image-based processes together. We anticipate that in the future eidomics will provide a universal and predictive imaging language that will change health care delivery.

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.

In-vivo kinetics of inhaled 5-aminolevulinic acid-induced protoporphyrin IX fluorescence in bronchial tissue

BACKGROUND

In the diagnosis of early-stage lung cancer photosensitizer-enhanced fluorescence bronchoscopy with inhaled 5-aminolevolinic acid (5-ALA) increases sensitivity when compared to white-light bronchoscopy. This investigation was to evaluate the in vivo tissue pharmacokinetics of inhaled 5-ALA within the bronchial mucosa in order to define the time optimum for its application prior to bronchoscopy.

METHODS

Patients with known or suspected bronchial carcinoma were randomized to receive 200 mg 5-ALA via inhalation 1, 2, 3, 4 or 6 hours before flexible fluorescence bronchoscopy was performed. Macroscopically suspicious areas as well as areas with visually detected porphyrin fluorescence and normal control sites were measured spectroscopically. Biopsies for histopathology were obtained from suspicious areas as well as from adjacent normal areas.

RESULTS

Fluorescence bronchoscopy performed in 19 patients reveals a sensitivity for malignant and premalignant changes (moderate dysplasia) which is almost twice as high as that of white-light bronchoscopy, whereas specificity is reduced. This is due to false-positive inflammatory lesions which also frequently show increased porphyrin fluorescence. Malignant and premalignant alterations produced fluorescence values that are up to 5 times higher than those of normal tissue. According to the pharmacokinetics of porphyrin fluorescence measured by spectroscopy, the optimum time range for 5-ALA application is 80-270 min prior to fluorescence bronchoscopy, with an optimum at 160 min.

CONCLUSION

According to our results we propose inhalation of 5-ALA 160 min prior to fluorescence bronchoscopy, suggesting that this time difference provides the best tumor/normal tissue fluorescence ratio.

Detection of pre-invasive endobronchial tumors with D-light/autofluorescence system

Autofluorescence bronchoscopy (AFB) is one of the newly developed diagnostic tools to detect the pre-cancerous lesions in the bronchial tissue. The utility of DLight/AFB in the detection of pre-cancerous lesions was compared to the standard white light bronchoscopy (WLB). In 113 patients (male 106, female 7), who visited hospital for evaluation of lung cancer, WLB and AFB were done and 364 biopsy specimens were obtained from November 2001 to August 2002. The bronchoscopic findings on WLB and AFB were compared to the pathological findings. The pathologic diagnoses of the specimens were as follows: normal in 96; hyperplasia in 69; metaplasia in 32; mild dysplasia in 13, moderate dysplasia in 6, severe dysplasia in 4; carcinoma in situ in 6; invasive carcinoma in 57. The relative sensitivity of adjunctive AFB to WLB vs. WLB alone was 1.5 in moderate dysplasia or worse lesions, and 3.2 in intraepithelial neoplasia. The specificity of adjunctive AFB and WLB alone were 0.91 and 0.5, respectively. The adjunctive AFB to the standard WLB increased the detection rate of the localized pre-invasive lesions. However, there was high rate of false positive in AFB.

Oral premalignancy: new methods of detection and treatment

Oral carcinogenesis proceeds through a stepwise accumulation of genetic damage over time. Because the oral cavity is easy to examine and risk factors for oral cancer are known, there is great opportunity to improve patient outcomes through diagnosis and treatment of pre-malignant lesions before the development of invasive oral carcinoma. This review provides a summary of developments in detection and diagnosis of oral premalignant lesions and innovative approaches to management of early oral neoplasia. These technological and therapeutic advances are much needed to improve the poor outcomes associated with oral cancer due to our inability to diagnose and treat this disease at an early, curable stage.

Genetic alteration and gene expression modulation during cancer progression

Cancer progresses through a series of histopathological stages. Progression is thought to be driven by the accumulation of genetic alterations and consequently gene expression pattern changes. The identification of genes and pathways involved will not only enhance our understanding of the biology of this process, it will also provide new targets for early diagnosis and facilitate treatment design. Genomic approaches have proven to be effective in detecting chromosomal alterations and identifying genes disrupted in cancer. Gene expression profiling has led to the subclassification of tumors. In this article, we will describe the current technologies used in cancer gene discovery, the model systems used to validate the significance of the genes and pathways, and some of the genes and pathways implicated in the progression of preneoplastic and early stage cancer.

Lung cancer . 3: Fluorescence bronchoscopy: clinical dilemmas and research opportunities

Recent developments in the detection of pre-invasive lesions of the large airways by fluorescence bronchoscopy are reviewed and the clinical and biological implications discussed.

Subepithelial vascular patterns in bronchial dysplasias using a high magnification bronchovideoscope

BACKGROUND

We have developed a method of high magnification bronchovideoscopy that enables improved observation of subepithelial vascular patterns of the bronchial mucosa. A study was undertaken to investigate the value of high magnification bronchovideoscopy in the detailed examination of dysplasia in the bronchial mucosa of patients with abnormal mucosal fluorescence.

METHODS

Thirty one patients with sputum cytology specimens suspicious or positive for malignancy were entered into the study. Conventional white light examination was first performed under local anaesthesia and fluorescence bronchoscopy was also carried out using a light induced fluorescence endoscopy (LIFE) lung system. A high magnification bronchovideoscope (XBF 200HM2) was then used to examine the microvascular network in the bronchial mucosa at sites of normal and abnormal fluorescence and the images obtained were compared with pathological diagnoses from bronchial biopsy specimens. Vascular area ratios were calculated using image analysing apparatus.

RESULTS

Vascular networks with regular patterns were observed at 20 of 22 abnormal fluorescence sites in biopsy specimens from patients with bronchitis. However, vascular networks with increased vessel growth and complex networks of tortuous vessels of various sizes were observed in 15 of 21 abnormal fluorescence sites in dysplasia specimens. There was a significant difference between bronchitis and dysplasia specimens (OR=25, 95% CI 5.5 to 113, p<0.0001). Mean vascular area ratios from 16 normal bronchial epithelium specimens with normal fluorescence, and 22 bronchitis and 21 dysplasia specimens with abnormal fluorescence were 0.054 (95% CI 0.039 to 0.07), 0.095 (95% CI 0.072 to 0.118), and 0.173 (95% CI 0.143 to 0.203), respectively. The results indicate a statistically significant increase in vascular area in the three groups (p<0.0001).

CONCLUSION

Areas of increased vessel growth and complex networks of tortuous vessels in the bronchial mucosa detected using a high magnification bronchovideoscope at sites of abnormal fluorescence may enable discrimination between bronchitis and dysplasia.