Detection of dysplasia and carcinoma in situ by ratio fluorometry

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.

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.

Preinvasive lesions of the bronchus

It has been proposed that invasive carcinoma of the bronchus develops through a transition from preinvasive lesions to overt malignancy. Newer diagnostic technologies have provided a more sensitive way to diagnose preinvasive lesions and a better understanding of the prevalence of such lesions. The natural history of preinvasive lesions has not been well defined; however, there is evidence that high-grade lesions are at a higher risk of progression to carcinoma. Molecular alterations have been described in preinvasive lesions and may help better predict which lesions will progress. Several noninvasive techniques are available for the treatment of high-grade lesions.

Has fluorescence spectroscopy come of age? A case series of oral precancers and cancers using white light, fluorescent light at 405 nm, and reflected light at 545 nm using the Trimira Identafi 3000

BACKGROUND

Optical spectroscopy devices are being developed and tested for the screening and diagnosis of cancer and precancer in multiple organ sites. The studies reported here used a prototype of a device that uses white light, green-amber light at 545 nm, and violet light at 405 nm. Given that oral neoplasia is rare, the need for a device that increases the sensitivity of comprehensive white light oral screening is evident. Such a device, in the hands of dentists, family practitioners, otorhinolaryngologists, general surgeons, obstetrician gynecologists, and internists, could greatly increase the number of patients who have lesions detected in the precancerous phase.

OBJECTIVES

The objective of this study was to present a case series of oral precancers and cancers that have been photographed during larger ongoing clinical trials.

METHODS

Over 300 patients were measured at 2 clinical sites that are comprehensive cancer centers and a faculty practice associated with a major dental school. Each site is conducting independent research on the sensitivity and specificity of several optical technologies for the diagnosis of oral neoplasia. The cases presented in this case series were taken from the larger database of images from the clinical trials using the aforementioned device. Optical spectroscopy was performed and biopsies obtained from all sites measured, representing abnormal and normal areas on comprehensive white light examination and after use of the fluorescence and reflectance spectroscopy device. The gold standard of test accuracy was the histologic report of biopsies read by the study histopathologists at each of the 3 study sites.

RESULTS

Comprehensive white light examination showed some lesions; however, the addition of a fluorescence image and a selected reflectance wavelength was helpful in identifying other characteristics of the lesions. The addition of the violet light-induced fluorescence excited at 405 nm provided an additional view of both the stromal neovasculature of the lesions and the stromal changes associated with lesion growth that were biologically indicative of stromal breakdown. The addition of 545 nm green-amber light reflectance increased the view of the keratinized image and allowed the abnormal surface vasculature to be more prominent.

CONCLUSIONS

Optical spectroscopy is a promising technology for the diagnosis of oral neoplasia. The conclusion of several ongoing clinical trials and an eventual randomized Phase III clinical trial will provide definitive findings that sensitivity is or is not increased over comprehensive white light examination.

Physician attitudes toward dissemination of optical spectroscopy devices for cervical cancer control: an industrial-academic collaborative study

BACKGROUND

Optical spectroscopy has been studied for biologic plausibility, technical efficacy, clinical effectiveness, patient satisfaction, and cost-effectiveness.

OBJECTIVE

We sought to identify health care provider attitudes or practices that might act as barriers or to the dissemination of this new technology.

METHODS

Through an academic-industrial partnership, we conducted a series of focus groups to examine physician barriers to optical diagnosis. The study was conducted in 2 stages. First, a pilot group of 10 physicians (8 obstetrician gynecologists and 2 family practitioners) was randomly selected from 8 regions of the United States and each physician was interviewed individually. Physicians were presented with the results of a large trial (N = 980) testing the accuracy of a spectroscopy-based device in the detection of cervical neoplasia. They were also shown a prototype of the device and were given a period of time to ask questions and receive answers regarding the device. They were also asked to provide feedback on a questionnaire that was then revised and presented to 3 larger focus groups (n = 13, 15, and 17 for a total N = 45). The larger focus groups were conducted during national scientific meetings with 20 obstetrician gynecologists and 25 primary care physicians (family practitioners and internists).

RESULTS

When asked about the dissemination potential of the new cervical screening technology, all study groups tended to rely on established clinical guidelines from their respective professional societies with regard to the screening and diagnosis of cervical cancer. In addition, study participants consistently agreed that real-time spectroscopy would be viewed positively by their patients. Participants were positive about the new technology's potential as an adjunct to colposcopy and agreed that the improved accuracy would result in reduced health care costs (due to decreased biopsies and decreased visits). Although all participants saw the potential of real-time diagnosis, there were many perceived barriers. These barriers included changes in scheduling and work-flow, liability, documentation, ease of use, length of training, device cost, and reimbursement by third-party payers.

CONCLUSIONS

Barriers exist to the dissemination of optical technologies into physician practice. These will need to be addressed before cervical screening and diagnosis programs can take advantage of spectroscopy-based instruments for cancer control.

Accuracy of optical spectroscopy for the detection of cervical intraepithelial neoplasia without colposcopic tissue information; a step toward automation for low resource settings

Optical spectroscopy has been proposed as an accurate and low-cost alternative for detection of cervical intraepithelial neoplasia. We previously published an algorithm using optical spectroscopy as an adjunct to colposcopy and found good accuracy (sensitivity=1.00 [95% confidence interval (CI)=0.92 to 1.00], specificity=0.71 [95% CI=0.62 to 0.79]). Those results used measurements taken by expert colposcopists as well as the colposcopy diagnosis. In this study, we trained and tested an algorithm for the detection of cervical intraepithelial neoplasia (i.e., identifying those patients who had histology reading CIN 2 or worse) that did not include the colposcopic diagnosis. Furthermore, we explored the interaction between spectroscopy and colposcopy, examining the importance of probe placement expertise. The colposcopic diagnosis-independent spectroscopy algorithm had a sensitivity of 0.98 (95% CI=0.89 to 1.00) and a specificity of 0.62 (95% CI=0.52 to 0.71). The difference in the partial area under the ROC curves between spectroscopy with and without the colposcopic diagnosis was statistically significant at the patient level (p=0.05) but not the site level (p=0.13). The results suggest that the device has high accuracy over a wide range of provider accuracy and hence could plausibly be implemented by providers with limited training.

Color fluorescence ratio for detection of bronchial dysplasia and carcinoma in situ

BACKGROUND

Autofluorescence bronchoscopy is more sensitive than conventional bronchoscopy for detecting early airway mucosal lesions. Decreased specificity can lead to excessive biopsy and increased procedural time. Onco-LIFE, a device that combines fluorescence and reflectance imaging, allows numeric representation by expressing red-to-green ratio (R/G ratio) within the region of interest. The aim of the study was to determine if color fluorescence ratio (R/G ratio) added to autofluorescence bronchoscopy could provide an objective means to guide biopsy.

METHODS

Subjects at risk for lung cancer were recruited at two centers: VU University Medical Centre (Amsterdam) and BC Cancer Agency (Canada). R/G ratio for each site appearing normal or abnormal was measured before biopsy. R/G ratios were correlated with pathology, and a receiver operating characteristic curve of R/G ratio for high-grade and moderate dysplasia was done. Following analysis of the training data set obtained from two centers, a prospective validation study was done.

RESULTS

Three thousand three hundred sixty-two adequate biopsies from 738 subjects with their corresponding R/G ratios were analyzed. R/G ratio 0.54 conferred 85% sensitivity and 80% specificity for the detection of high-grade and moderate dysplasia, area under the curve was 0.90, and 95% confidence interval was 0.88 to 0.92. In another 70 different sites that were assessed, kappa measurements of agreement of R/G ratios with visual scores and pathology were 0.66 (P < 0.0001) and 0.61 (P < 0.0001), respectively. R/G ratio combined with visual score improved specificity to 88% (95% confidence interval, 0.73-0.96) for high-grade and moderate dysplasia.

CONCLUSION

Color fluorescence ratio can objectively guide the bronchoscopist in selecting sites for biopsy with good pathologic correlation.

Intrinsic fluorescence spectroscopy for endoscopic detection and localization of the endobronchial cancerous lesions

Fluorescence spectroscopy contains diagnostic information about the lung biochemistry and morphology, including tissue optical properties and fluorophores. However, the fluorophore information is generally masked by the optical properties of the tissue, which complicates the evaluation of their role in lung-cancer detection. In this work, we have developed a method for extracting the intrinsic fluorescence spectra from the endoscopic measurements of the combined fluorescence and reflectance spectra. Principle components and classification analysis was performed to evaluate the diagnostic potential of the extracted intrinsic fluorescence spectra from in vivo combined fluorescence and reflectance spectral measurements. We evaluated the diagnostic sensitivity and specificity of both the intrinsic fluorescence and the fluorescence spectra. The results showed that the intrinsic fluorescence spectra contain significant diagnostic information that had been masked by the lung optical properties. We have also found that the intrinsic fluorescence has improved the specificity for endobronchial-cancer detection, although with a slight decrease in the detection sensitivity, when compared to the fluorescence spectra. This may indicate that intrinsic fluorescence analysis could be used to improve the diagnostic specificity of fluorescence spectroscopy and imaging.

Bronchial Intraepithelial Neoplasia/Early Central Airways Lung Cancer

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

In vivo assessment and evaluation of lung tissue morphologic and physiological changes from non-contact endoscopic reflectance spectroscopy for improving lung cancer detection

We present a method for lung cancer detection exploiting reflectance spectra measured in vivo during endoscopic imaging of the lung. The measured reflectance spectra were analyzed using a specially developed light-transport model to obtain quantitative information about cancer-related, physiological, and morphologic changes in the superficial bronchial mucosa layers. The light-transport model allowed us to obtain the absorption coefficient (mua) and further to derive the micro-vascular blood volume fraction in tissue and the tissue blood oxygen saturation. The model also allowed us to obtain the scattering coefficient (mus) and the anisotropy coefficient (g) and further to derive the tissue scattering micro-particle volume fraction and size distribution. The specular component of the reflectance signal and the instrument response were accounted for during the analysis. The method was validated using 100 reflectance spectra measured in vivo in a noncontact fashion from 22 lung patients (50 normal tissue/benign lesion sites and 50 malignant lesion sites). The classification between normal tissue/benign lesions and malignant lesions was further investigated using the derived quantitative parameters and discriminant function analysis. The results demonstrated significant differences between the normal tissue/benign lesions and the malignant lesions in terms of tissue blood volume fraction, blood oxygen saturation, tissue scatterer volume fractions, and size distribution. The results also showed that the malignant lung lesions can be differentiated from normal tissue/benign lesions with both diagnostic sensitivity and specificity of better than 80%.

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.

Autofluorescence Bronchoscopy and Endobronchial Ultrasound: A Practical Review

Endobronchial ultrasound (EBUS) and autofluorescence bronchoscopy (AFB) are the two technologies to have the largest impact on diagnostic bronchoscopy in the last forty years. The AFB utilizes inherent tissue properties to identify preinvasive lesions of the central airways. The EBUS can accurately define airway invasion versus compression from tumors, guide transbronchial needle aspiration of hilar and mediastinal lymph nodes, and predict, based on ultrasound morphology, whether peripheral nodules are benign or malignant. It is also extremely useful for determining the proximal and distal extent of tumors in and around the airway, and aid in surgical planning. This article will review the principles and clinical applications of these two technologies.

Fluorescent bronchoscopy: contribution for lung cancer screening?

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

New methods for early diagnosis of lung cancer

The recent promising results with low-dose CT have stimulated the revival of the scientific discussion on screening for early lung cancer and mark the end of a significant period with lack of progress. At the same time positron emission tomography has quickly shown its value as a staging tool. Also new endobronchial techniques such as autofluorescence bronchoscopy and endobronchial ultrasonography have shown remarkably increased sensitivity when used by experienced hands. Cytopathological risk markers in sputum are being developed and it is expected that combinations of these new diagnostic methods will help to increase the identification of asymptomatic lung cancer patients and turn into better survival figures.

Fluorescein electronic endoscopy: a novel method for detection of early stage gastric cancer not evident to routine endoscopy

BACKGROUND

Fluorescence endoscopy with fluorescein sodium in the stomach was evaluated by using a newly developed fluorescence electronic endoscopic system.

METHODS

Sixteen patients with early stage gastric cancer diagnosed by white light endoscopy and chromoendoscopy underwent fluorescein electronic endoscopy before surgery. The resection specimens underwent thorough histopathologic evaluation.

RESULTS

About 10 seconds after intravenous injection of fluorescein, fluorescence appeared and immediately spread throughout the gastric surface. A few minutes later, differentiated early stage gastric cancers with more abundant stroma than surrounding normal mucosa exhibited significantly stronger fluorescence, and those with less stroma exhibited weaker fluorescence than the surrounding normal mucosa. Undifferentiated early stage gastric cancers, in which the stroma became wider because foveolae were collapsed from malignant invasion, expressed stronger fluorescence intensity. In all cases, the borders of early stage gastric cancers were clearly demonstrated. Among the 16 patients, 6 accompanying flat lesions and 1 tiny lesion not evident by routine endoscopy were detected. The extent of the cancers, as determined by fluorescence endoscopy, were similar to those determined histopathologically.

CONCLUSIONS

Fluorescein electronic endoscopy is useful in determining the extent within the mucosa of gastric cancers when this is obscure by standard endoscopic observation, and for detecting extremely early stage cancer that is not evident by conventional endoscopic observation.

Fluorescence spectroscopy as a biomarker in a cell culture and in a nonhuman primate model for ovarian cancer chemopreventive agents

OBJECTIVE

The objective of this study was to compare the effects of chemopreventive agents on natural fluorescence emission of ovarian cells in a cell culture and in a primate model as a feasibility trial to monitor drug activity.

METHODS

Fluorescence emission spectra were collected from normal (NOE) and immortalized ovarian surface epithelial cells at 290, 360, and 450 nm excitation. Redox potentials were calculated and compared to % apoptosis and cell survival. Fluorescence emission spectra were collected from 18 female rhesus macaques receiving fenretinide [N-(-hydroxyphenyl)retinamide (4-HPR)] orally and/or oral contraceptive pills (OCP) or no medication. Fluorescence intensities and redox ratios were compared using a two-tailed Student's t test.

RESULTS

Apoptosis and cell survival correlated with fluorescence emission consistent with metabolically active proteins [flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide (NAD(P)H)] and the resulting redox ratio in cells grown with 4-HPR. The 4-HPR consistently inhibited cell survival in a dose dependent manner. Degree of correlation varied between different cell lines. In primates receiving 4-HPR, fluorescence emission was increased at 450 nm excitation, 550 nm emission consistent with FAD presence, whereas those receiving OCP showed decreased emission at 350 nm excitation, 450 nm emission consistent with decreased NAD(P)H presence. Redox ratios were increased by both drugs.

CONCLUSIONS

Fluorescence intensity and redox ratio appear to be altered by 4-HPR treatment in vivo and in cell culture and by OCP in vivo. Fluorescence intensity may be useful to monitor chemopreventive agents in clinical trials.

Methods and devices for the management of term and preterm labor

In this review, we outline studies showing that the uterus (myometrium) and cervix pass through a conditioning step in preparation for labor. This step is not easily identifiable with present methods designed to assess the uterus or cervix. In the uterus, this seemingly irreversible step consists of changes in the electrical properties that make muscle more excitable and responsive and produce forceful contractions. In the cervix, the step consists of softening of the connective tissue components. Progesterone and nitric oxide appear to have important roles in these processes. The progress of labor can be assessed noninvasively using electromyographic (EMG) signals from the uterus (the driving force for contractility) recorded from the abdominal surface. Uterine EMG bursts detected in this manner characterize uterine contractile events during human and animal pregnancy. A low uterine EMG activity, measured transabdominally throughout most of pregnancy, rises dramatically during labor. EMG activity also increases substantially during preterm labor in humans and rats and may be predictive of preterm labor. A quantitative method for assessing the cervix is also described. A collascope estimates cervical collagen content from a fluorescent signal generated when collagen crosslinks are illuminated with an excitation light of about 340 nm. The system has proved useful in rats and humans at various stages of pregnancy and indicates that cervical softening occurs progressively in the last one-third of pregnancy. In rats, collascope readings correlate with resistance measurements made in the isolated cervix, which may help to assess cervical function during pregnancy and indicate controls and treatments.

Autofluorescence characteristics of immortalized and carcinogen-transformed human bronchial epithelial cells

Tissue autofluorescence has been explored as a potential method of noninvasive pre-neoplasia (pre-malignancy) detection in the lung. Here, we report the first studies of intrinsic cellular autofluorescence from SV40 immortalized and distinct tobacco-carcinogen-transformed (malignant) human bronchial epithelial cells. These cell lines are useful models for studies seeking to distinguish between normal and pre-neoplastic human bronchial epithelial cells. The cells were characterized via spectrofluorimetry and confocal fluorescence microscopy. Spectrofluorimetry revealed that tryptophan was the dominant fluorophore. No change in tryptophan emission intensity was observed between immortalized and carcinogen-transformed cells. Confocal autofluorescence microscopy was performed using a highly sensitive, spectrometer-coupled instrument capable of limiting emission detection to specific wavelength ranges. These studies revealed two additional endogenous fluorophores, whose excitation and emission characteristics were consistent with nicotinamide adenine dinucleotide (NADH) and flavins. In immortalized human bronchial epithelial cells, the fluorescence of these species was localized to cytoplasmic granules. In contrast, the carcinogen-transformed cells showed an appreciable decrease in the fluorescence intensity of both NADH and flavins and the punctate, spatial localization of the autofluorescence was lost. The observed autofluorescence decrease was potentially the result of changes in the redox state of the fluorophores. The random cytoplasmic fluorescence pattern found in carcinogen-transformed cells may be attributed to changes in the mitochondrial morphology. The implications of these results to pre-neoplasia detection in the lung are discussed.

New diagnostic methods for esophageal carcinoma

The increasingly severe problem of esophageal carcinoma on world public health merits the application of new endoscopic methods to assist in early detection and screening. Older methods, such as tissue staining, combined with magnification endoscopy, have shown promising results, while newer techniques capitalize on measurements that discriminate benign from malignant cells based on a wide array of different attributes, ranging from the molecular to the macroscopic level. Instrumentation based on laser-induced fluorescence spectroscopy, ratio fluorescence imaging, elastic scattering spectroscopy, Raman spectroscopy, and optical coherence tomography is presently being tested and compared with standard endoscopic techniques. Using pathologic interpretation of pinch biopsies as the "gold standard," these techniques have shown the ability to identify dysplastic or malignant regions of tissue that would not be visible to the unassisted endoscopist and offer increased sensitivity for detection compared to rigorous random biopsy protocols. The rapid speed of the instruments allows the provision of information to the endoscopist almost instantaneously, potentially allowing therapeutic decisions to be conducted within the confines of the same endoscopic procedure, thereby achieving gains in efficiency and reductions in overall cost. Large, multicenter trials will be necessary to determine the sensitivity and specificity of individual and combined techniques, as well as their ability to favorably influence the early detection, management, and overall outcome of this disease.

A pilot study of autofluorescent endoscopy for the in vivo detection of laryngeal cancer

OBJECTIVES

To determine the advantage of autofluorescent endoscopy for the identification of laryngeal cancer.

STUDY DESIGN

This is a prospective, multicenter clinical study. We investigated whether autofluorescent endoscopy using the Lung Imaging Fluorescent Endoscopy (LIFE)-Lung System (Xillix, Olympus) is capable of identifying early cancer of the larynx, especially in comparison with conventional white-light endoscopy and microscopic laryngoscopy. Benign lesions as well as microinvasive and invasive squamous cell carcinoma of the larynx were investigated. For logistic reasons and because of the pilot character of this study, the number of patients was limited.

METHODS

Sixteen patients having 24 laryngeal lesions of both benign or malignant character were subsequently examined by autofluorescent endoscopy, white-light endoscopy, and microscopic laryngoscopy. Based on optical appearance, and for each method separately, the lesions were classified as malignant or not. The visual results were documented and histologically verified.

RESULTS

The sensitivity of autofluorescent endoscopy for laryngeal cancer detection was more than 90% and therefore higher than that of white-light endoscopy and microscopic laryngoscopy. However, as far as laryngeal cancer is concerned, the specificity of autofluorescent endoscopy was very low. Many of the false-positive results were due to inflammation, hypervascularization, and edema.

CONCLUSION

Autofluorescent endoscopy is advantageous only in the hands of an experienced ENT specialist. Although it does not replace the combination of white-light endoscopy and a critical evaluation of the clinical symptoms of the individual disease, it can profitably complement them. Autofluorescent endoscopy can help in determining whether microscopic laryngoscopy performed with general anesthesia should be recommended urgently to the patient. Microscopic laryngoscopy remains the best method for the identification of malignant lesions, if it is combined with obtaining taking multiple biopsy specimens. Confirmation of the results of this pilot study with a larger series of patients is desirable.

Prevention of cervix cancer

Cervix carcinoma is an important health problem world-wide, being the second most common cancer among women, ranking first in many developing countries. A number of important epidemiological risk factors have been identified as contributing to the development of CIN and invasive cervix carcinoma. Of key importance is infection with human papillomavirus (HPV), which is the primary risk factor. There are evolving primary and secondary preventive strategies that could further reduce the burden from cervical carcinoma. The possible primary preventive strategies include risk reduction, diet or dietary supplements, HPV vaccines, and other chemopreventive agents. The possible advances in secondary preventive strategies include new technologies for Pap smears, HPV typing triage, and other adjuvant screening procedures. The impact of these strategies will depend upon evidence to support their use along with the characteristics of the population and environment in which they are used.

Fluorescence spectroscopy of neoplastic and non-neoplastic tissues

Fast and non-invasive, diagnostic techniques based on fluorescence spectroscopy have the potential to link the biochemical and morphologic properties of tissues to individual patient care. One of the most widely explored applications of fluorescence spectroscopy is the detection of endoscopically invisible, early neoplastic growth in epithelial tissue sites. Currently, there are no effective diagnostic techniques for these early tissue transformations. If fluorescence spectroscopy can be applied successfully as a diagnostic technique in this clinical context, it may increase the potential for curative treatment, and thus, reduce complications and health care costs. Steady-state, fluorescence measurements from small tissue regions as well as relatively large tissue fields have been performed. To a much lesser extent, time-resolved, fluorescence measurements have also been explored for tissue characterization. Furthermore, sources of both intrinsic (endogenous fluorophores) and extrinsic fluorescence (exogenous fluorophores) have been considered. The goal of the current report is to provide a comprehensive review on steady-state and time-resolved, fluorescence measurements of neoplastic and non-neoplastic, biologic systems of varying degrees of complexity. First, the principles and methodology of fluorescence spectroscopy are discussed. Next, the endogenous fluorescence properties of cells, frozen tissue sections and excised and intact bulk tissues are presented; fluorescence measurements from both animal and human tissue models are discussed. This is concluded with future perspectives.

Detection of bronchial preneoplastic lesions and early lung cancer with fluorescence bronchoscopy: a study about its ambulatory feasibility under local anaesthesis

BACKGROUND

Autofluorescence bronchoscopy (AB) enhances the bronchoscopist's ability to diagnose bronchial preneoplastic lesions and early cancer. We undertook a study to assess its feasibility and performance under local anaesthesia on a real ambulatory mode.

METHODS

Thirty-four consecutive patients at very high risk for lung cancer were prospectively studied by AB under local anaesthesia, without any sedation. Lidocaine doses, time, oxygen saturation, peak expiratory flow (PEF) and the number of cough episodes were measured. Continuous assessment of the respiratory sensation was obtained with a visual analog scale. A total of 172 biopsies were performed in abnormal and normal areas.

RESULTS

The procedure was long-lasting (mean +/- SD: 26.6 +/- 6.0 min), required high total doses of Lidocaine (660 +/- 107 mg) without any significant side effect, and was associated with significant decreases in O2 saturation from 98.5 +/- 1.4 to 96.1 +/- 2.5% and in PEF from 380 +/- 96 to 310 +/- 78 l/min. However, the cough counts were moderate and the majority of patients reported no respiratory discomfort. 62 hyperplasia, metaplasia, dysplasia and carcinoma in situ (CIS) were detected and the relative sensitivity of AB +/- white-light bronchoscopy (WLB) versus WLB alone was 3.75 for intraepithelial lesions corresponding to moderate dysplasia or worse.

CONCLUSIONS

AB, a procedure that increases our ability to recognize preneoplastic lesions and early lung cancer, can be performed under local anaesthesia, without systemic sedation in patients at very high risk for lung cancer.

Instrumentation for the diagnosis of term and preterm labour

The problems associated with labor during pregnancy are among the most important health issues facing physicians. Understanding the role of the uterus and cervix in labor and developing methods to control their function is essential to solving problems relating to labor. At the moment, only crude, inaccurate and subjective methods are used to assess changes in the uterus and cervix that occur in preparation for or during labor. In the past several years, we have developed noninvasive methods to quantitatively evaluate the uterus and cervix based respectively on recording of uterine electrical signals from the abdominal surface (uterine EMG) and measurement of light-induced cervical collagen fluorescence (LIF) with an optical device (Collascope). The methods are rapid and allow assessment of uterine contractility and cervical ripening. Studies in rats and humans indicate that uterine and cervical function can be successfully monitored during pregnancy using these approaches and that these techniques might be used in a variety of conditions associated with labor to better define management. The potential benefits of the proposed instrumentation and methods include a reducing the rate of preterm delivery, improving maternal and perinatal outcome, monitoring treatment, decreasing cesarean section rate and improving research methods to understand uterine and cervical function.

In vivo identification of colonic dysplasia using fluorescence endoscopic imaging

BACKGROUND

Previous in vitro studies showed that autofluorescence images of colonic mucosa collected endoscopically can be used to detect dysplasia with high sensitivity. This method is extended to the collection of fluorescence images of adenomatous polyps in vivo.

METHODS

Fluorescence images were collected during colonoscopy in 30 patients. A total of 12 adenomatous and 6 hyperplastic polyps were identified. A fiberoptic excitation probe, located in the instrument channel of the colonoscope, delivered 300 mW of near-ultraviolet light at lambdaex = 351 and 364 nm. Mucosal fluorescence in the spectral bandwidth between 400 and 700 nm was imaged, processed, and displayed with various likelihoods of associated dysplasia.

RESULTS

Adenomatous polyps exhibited decreased fluorescence intensity compared with adjacent mucosa with normal appearance. With the fluorescence threshold set to 80% of the average intensity of normal mucosa, a sensitivity of 83% for dysplasia identification was achieved. All hyperplastic polyps were correctly identified as being non-dysplastic. Optimal identification of dysplastic regions was obtained with the colonoscope oriented at a near-normal angle of incidence to the polyps. At higher angles of incidence, artifacts caused by illumination shadows were introduced.

CONCLUSIONS

The dysplasia associated with adenomatous polyps can be identified in vivo by fluorescence imaging with high sensitivity, thus demonstrating the potential to guide endoscopic procurement of biopsy specimens.

Mathematical model of fluorescence endoscopic image formation

We present a mathematical model that describes the spatial distribution of photons in fluorescence endoscopic images, resulting in expressions for image signal-to-noise ratio and resolution. This model was applied to quantitative analysis of fluorescence images collected from human colonic mucosa with a fiber-optic and an electronic endoscope. It provides a tool for the design of fluorescence endoscopic imaging systems and for extraction of quantitative information about image features. The results apply generally to endoscopic imaging of remote structures in biological and industrial settings, in which light of weak intensity such as fluorescence as well as reflected white light is used.

Recent advances in the use of lasers in otolaryngology

The laser (Light Amplification by Stimulated Emission of Radiation) has been used in Otolaryngology for over 20 years and is by now an accepted part of the armamentarium. A tremendous amount of work is being done in refining existing techniques and developing new ones, and this review discusses some of the recent advances.

Diagnosis of head and neck precancerous lesions in an animal model using fluorescence spectroscopy

Laser-induced fluorescence (LIF) of tissues depends on their biochemical and histomorphologic characteristics. LIF spectroscopic properties of 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced precancerous and early cancerous lesions in a hamster buccal pouch mucosa model were studied. Fluorescence spectra from neoplastic lesions showed a characteristic fluorescence peak in the red region of the visible spectrum centered between 630 and 640 nm when excited with 410-nm light. Using this as a diagnostic criterion, 45 of 49 lesions studied were correctly diagnosed, including early dysplastic lesions. Follow-up study of four dysplastic lesions over 2 weeks revealed an increase in red fluorescence intensity. The findings of these experiments suggest that LIF spectroscopy may be a valuable noninvasive technique not only for early diagnosis of head and neck cancer, but also to probe a possible biochemical surrogate biomarker in the follow-up of suspected lesions.

Autofluorescence characteristics of oral mucosa

BACKGROUND

The fluorescence characteristics of tissues depend upon their biochemical composition and histomorphological architecture, both of which undergo a change during malignant transformation. These changes are detectable as an alteration in the fluorescence spectral profile of the tissues.

METHODS

Biopsy specimens from clinically suspicious lesions and normal-appearing oral mucosa were obtained from patients. Fluorescence spectroscopic measurements were obtained to study the differences between normal and dysplastic tissues and to determine the most appropriate excitation wavelength(s) for exploiting these differences.

RESULTS

Fluorescence spectra from a total of 12 histologically normal (healthy mucosa or benign lesions) and ten abnormal (dysplastic or malignant) tissue samples were compared. Significant spectral differences were seen between the two groups. These differences were most marked at the excitation wavelength of 410 nm. Using this wavelength, fluorescence correctly diagnosed 20 of 22 samples studied.

CONCLUSIONS

This technique accurately differentiates normal from abnormal tissues in vitro and has the potential applications for in vivo use as a noninvasive diagnostic tool.

Cervical precancer detection using a multivariate statistical algorithm based on laser-induced fluorescence spectra at multiple excitation wavelengths

A portable fluorimeter was developed and utilized to acquire fluorescence spectra from 381 cervical sites in 95 patients at 337, 380 and 460 nm excitation immediately prior to colposcopy. A multivariate statistical algorithm was used to extract clinically useful information from tissue spectra acquired in vivo. Two full-parameter algorithms were developed using tissue fluorescence emission spectra at all three excitation wavelengths (161 excitation-emission wavelength pairs) for cervical precancer (squamous intraepithelial lesion [SIL]) detection: a screening algorithm that discriminates between SIL and non-SIL with a sensitivity of 82 +/- 1.4% and specificity of 68 +/- 0.0%, and a diagnostic algorithm that differentiates high-grade SIL from non-high-grade SIL with a sensitivity and specificity of 79 +/- 2% and 78 +/- 6%, respectively. Multivariate statistical analysis was also employed to reduce the number of fluorescence excitation-emission wavelength pairs needed to redevelop algorithms that demonstrate a minimum decrease in classification accuracy. Two reduced-parameter algorithms that employ fluorescence intensities at only 15 excitation-emission wavelength pairs were developed: the screening algorithm differentiates SIL from non-SIL with a sensitivity of 84 +/- 1.5% and specificity of 65 +/- 2% and the diagnostic algorithm discriminates high-grade SIL from non-high-grade SIL with a sensitivity and specificity of 78 +/- 0.7% and 74 +/- 2%, respectively. Both the full-parameter and reduced-parameter screening algorithms discriminate between SIL and non-SIL with a similar specificity (+/-5%) and a substantially improved sensitivity relative to Pap smear screening. A comparison of the full-parameter and reduced-parameter diagnostic algorithms to colposcopy in expert hands indicates that all three have a very similar sensitivity and specificity for differentiating high-grade SIL from non-high-grade SIL.

Native cellular fluorescence identifies terminal squamous differentiation of normal oral epithelial cells in culture: a potential chemoprevention biomarker

Native cellular fluorescence (NCF) is being investigated as an intermediate endpoint biomarker for chemoprevention. Oral epithelial cells were cultured under three conditions to identify a spectral pattern for epithelial differentiation: cells maintained in serum-free keratinocyte growth medium were the least differentiated (KGM cells); cells switched to DMEM/F12 plus 10% FCS were intermediate in differentiation (DMEM/F12/FCS cells); DMEM/F12/FCS cells switched to serum-free DMEM/F12 plus 0.8 M NaCl to induce cornified envelopes were the most differentiated (DMEM/F12/NaCl cells). The differentiation status was characterized using immunohistochemistry and electron microscopy. NCF analysis was able to distinguish terminally differentiated epithelial cells (DMEM/F12/NaCl) from those less differentiated cells (KGM, DMEM/F12/FCS) in several emission (lambda ex 340 nm, lambda em 360-660 nm; lambda ex 365 nm, lambda em 400-700 nm; lambda ex 420 nm, lambda em 440-800 nm) and excitation scans (lambda ex 200-360 nm; lambda em 380 nm, lambda ex 240-430 nm; lambda em 450 nm, lambda ex 250-460 nm, lambda em 480 nm; lambda ex 270-500 nm, lambda em 520 nm). The ability to discriminate terminal differentiation in this in vitro model supports the concept of using NCF as an intermediate biomarker to monitor in vivo mucosal differentiation.

Development of a multivariate statistical algorithm to analyze human cervical tissue fluorescence spectra acquired in vivo

BACKGROUND AND OBJECTIVE

A general multivariate statistical algorithm has been developed to analyze the diagnostic content of cervical tissue fluorescence spectra acquired in vivo.

MATERIALS AND METHODS

The primary steps of the algorithm are to: (1) preprocess the data to reduce inter-patient and intra-patient variation of tissue spectra within a diagnostic category, without a priori information, (2) dimensionally reduce the preprocessed fluorescence emission spectrum with minimal information loss and use it to select the minimum number of the original emission variables of the fluorescence spectrum required to achieve classification with negligible decrease in predictive ability, and (3) assign a posterior probability to the diagnosis of each sample, so that samples with relative uncertain diagnosis can be reevaluated by a clinician. The algorithm was tested retrospectively and prospectively on cervical tissue spectra acquired from 476 sites from 92 patients at 337 nm excitation.

RESULTS

The algorithm based on the entire fluorescence spectrum differentiates squamous intraepithelial lesions (SILs) from normal squamous epithelia and inflammation with an average sensitivity and specificity of 88% +/- 1.4 and 70% +/- 1, respectively. The average sensitivity and specificity of the identical algorithm based on intensity selected at only two emission wavelengths is 88% +/- 1.4 and 71% +/- 1.4, respectively.

CONCLUSION

The multivariate statistical algorithm based on both types of spectral inputs at 337 nm excitation has a similar sensitivity and significantly improved specificity relative to colposcopy in expert hands.

In vivo diagnosis of cervical intraepithelial neoplasia using 337-nm-excited laser-induced fluorescence

Laser-induced fluorescence at 337-nm excitation was used in vivo to differentiate neoplastic [cervical intraepithelial neoplasia (CIN)], nonneoplastic abnormal (inflammation and human papilloma viral infection), and normal cervical tissues. A colposcope (low-magnification microscope used to view the cervix with reflected light) was used to identify 66 normal and 49 abnormal (5 inflammation, 21 human papilloma virus infection, and 23 CIN) sites on the cervix in 28 patients. These sites were then interrogated spectroscopically. A two-stage algorithm was developed to diagnose CIN. The first stage differentiated histologically abnormal tissues from colposcopically normal tissues with a sensitivity, specificity, and positive predictive value of 92%, 90%, and 88%, respectively. The second stage differentiated preneoplastic and neoplastic tissues from nonneoplastic abnormal tissues with a sensitivity, specificity, and positive predictive value of 87%, 73%, and 74%, respectively. Spectroscopic differences were consistent with a decrease in the absolute contribution of collagen fluorescence, an increase in the absolute contribution of oxyhemoglobin attenuation, and an increase in the relative contribution of reduced nicotinamide dinucleotide phosphate [NAD(P)H] fluorescence as tissue progresses from normal to abnormal in the same patient. These results suggest that in vivo fluorescence spectroscopy of the cervix can be used to diagnose CIN at colposcopy.

Small cell lung cancer: etiology, biology, clinical features, staging, and treatment

Lung cancer is the leading cause of cancer death in the United States. Small cell lung cancer (SCLC) accounts for 20% to 25% of all bronchogenic carcinoma and is associated with the poorest 5-year survival of all histologic types. SCLC differs in its etiologic, pathologic, biologic, and clinical features from non-SCLC, and these differences have translated to distinct approaches to its prevention and treatment. Compared with other histologic types of lung cancer, exposures to tobacco smoke, ionizing radiation, and chloromethyl ethers pose a substantially greater risk for development of SCLC. The histologic classification of SCLC has been revised to include three categories: (1) small cell carcinoma, (2) mixed small cell/large cell, and (3) combined small cell carcinoma. Ultrastructurally, SCLC displays a number of neuroendocrine features in common with pulmonary neuroendocrine cells, including dense core vesicles or neurosecretory granules. These dense core vesicles are associated with a variety of secretory products, cell surface antigens, and enzymes. The biology of SCLC is complex. The activation of a number of dominant proto-oncogenes and the inactivation of tumor suppressor genes in SCLC have been described. Dominant proto-oncogenes that have been found to be amplified or overexpressed in SCLC include the myc family, c-myb, c-kit, c-jun, and c-src. Altered expression of two tumor suppressor genes in SCLC, p53 and the retinoblastoma gene product, has been demonstrated. Cytogenetic and molecular evidence for chromosomal loss of 3p, 5q, 9p, 11p, 13q, and 17p in SCLC has intensified the search for other tumor suppressor genes with potential import in this malignancy. Bombesin/gastrin-releasing peptide, insulin-like growth factor I, and transferrin have been identified as autocrine growth factors in SCLC, with a number of other peptides under active investigation. Several mechanisms of drug resistance in SCLC have been described, including gene amplification, the recently described overexpression of multi-drug resistance-related protein (MRP), and the expression of P-glycoprotein. The classic SCLC staging system has been supplanted by a revised TNM staging system where limited disease and extensive disease are equivalent to the TNM stages I through III and stage IV, respectively. Therapeutically, recent strategies have attained small improvements in survival but significant reductions in the toxicities of chemotherapeutic regimens. Presently, the overall 5-year survival for SCLC is 5% to 10%, with limited disease associated with a significantly higher survival rate.(ABSTRACT TRUNCATED AT 400 WORDS)