Autofluorescence imaging in the diagnosis of laryngeal cancer

Diagnostic Assessment (Imaging) and Staging of Laryngeal Cancer

Diagnosis of larynx cancer relies on a detailed history and physical and objective assessment with endoscopy and imaging. Endoscopy is needed to assess for vocal fold function that directly affects staging. Computed tomography and MRI can be used to assess for tumor extent in relation to intra- and extra-laryngeal structures, especially paraglottic and pre-epiglottic space involvement as well as cartilage invasion. Accurate staging is critical for subsequent treatment decision-making regarding larynx preservation.

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

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

Diagnostic value of autofluorescence laryngoscope in early laryngeal carcinoma and precancerous lesions: A systematic review and meta-analysis

OBJECTIVE

We aim to evaluate the diagnostic value of autofluorescence laryngoscope (AFL) in early laryngeal carcinoma and precancerous lesions. aWe also assess the value of AFL in diagnosis of early laryngeal carcinoma and precancerous lesions in comparison with that of white light laryngoscope (WL).

METHODS

The databases consisting of PubMed, Cochrane Library, Web of science and CNKI were systematically searched to find pertinent literatures of AFL in diagnosing early laryngeal carcinoma and precancerous lesions. We made a quality evaluation of every study we included using the modified Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). The pooled sensitivities, specificities were calculated using Meta-Disc 1.4. And we estimated the summary receiver operating characteristic curves (SROC) and area under the curves (AUC).

RESULTS

We finally included 23 studies. The results of AFL in diagnosing early laryngeal carcinoma and precancerous lesions showed higher sensitivity of 0.91 (95%CI: 0.89-0.93; χ²=43.78, p = 0.0025) and specificity of 0.80 (95%CI: 0.77-0.82; χ²=130.64, p = 0.000), and the weighted AUC of AFL was 0.948 ± 0.013 (95%CI: 0.921-0.974) and the diagnostic accuracy (Q*) was 0.887 ± 0.018. The sensitivity and specificity of WL were 0.74 (95%CI: 0.70-0.77; χ²=52.40, p = 0.000) and 0.89 (95%CI: 0.87-0.90; χ²=299.22, p = 0.000), and the weighted AUC of WL was 0.835 ± 0.029 (95%CI: 0.777-0.892) and the diagnostic accuracy (Q*) was 0.767 ± 0.027.

CONCLUSION

The meta-analysis and systematic review suggested that AFL had high diagnostic value in early laryngeal carcinoma and precancerous lesions, and its diagnostic value was higher than that of WL. These results indicated that AFL can provide good guidance for the early detection of laryngeal carcinoma and precancerous lesions.

Guidelines for the Surgical Management of Laryngeal Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to develop clinical practice guidelines for the surgical treatment of laryngeal cancer. This Task Force conducted a systematic search of the EMBASE, MEDLINE, Cochrane Library, and KoreaMed databases to identify relevant articles, using search terms selected according to the key questions. Evidence-based recommendations were then created on the basis of these articles. An external expert review and Delphi questionnaire were applied to reach consensus regarding the recommendations. The resulting guidelines focus on the surgical treatment of laryngeal cancer with the assumption that surgery is the selected treatment modality after a multidisciplinary discussion in any context. These guidelines do not, therefore, address non-surgical treatment such as radiation therapy or chemotherapy. The committee developed 62 evidence-based recommendations in 32 categories intended to assist clinicians during management of patients with laryngeal cancer and patients with laryngeal cancer, and counselors and health policy-makers.

[Noninvasive imaging using autofluorescence endoscopy: Value for the early detection of laryngeal cancer]

BACKGROUND

Autofluorescence endoscopy is able to delineate malignancy from normal tissue by color change. The objective of the present study was to assess the value of this noninvasive imaging method for the early detection of laryngeal cancer and its precursor lesions.

PATIENTS AND METHODS

In a prospective study, 152 patients with a laryngeal lesion who were undergoing microlaryngoscopy were investigated. Autofluorescence endoscopy was performed after conventional white light endoscopy, just before excisional biopsy was carried out for histologic verification.

RESULTS

In the early detection of laryngeal cancer and its precursor lesions, autofluorescence endoscopy showed a significantly higher sensitivity (98 vs. 88%) and accuracy (97 vs. 90%) than white light endoscopy alone, whereas the specificity (97 vs. 93%) was essentially equal in both methods.

CONCLUSION

Autofluorescence endoscopy qualifies as a simple screening procedure for rapid detection of suspicious lesions and assessment of their horizontal extension. This allows for guided biopsy or tumor resection, and can also be used in oncological follow-up.

Effectiveness of narrow band imaging in the detection of premalignant and malignant lesions of the larynx: validation of a new endoscopic clinical classification

BACKGROUND

The purpose of this study was to assess the value of narrow band imaging (NBI) endoscopy in the diagnosis of pharyngolaryngeal lesions and to demonstrate the validity of a new NBI-based classification of their vascular pattern.

METHODS

From 2009 to 2011, 248 patients with pharyngolaryngeal lesions underwent NBI-endoscopic evaluation. NBI findings were classified into 5 types according to the Ni classification and were compared with histopathological reports. Sensitivity, specificity, accuracy, and positive predictive value (PPV) and negative predictive value (NPV) were calculated.

RESULTS

Sensitivity, specificity, accuracy, PPV, and NPV were 97.4%, 84.6%, 92.7%, 91.6%, and 95.1%, respectively. Ninety-eight percent of histologically malignant lesions corresponded to type V endoscopic pattern, whereas 84.8% of the non-neoplastic lesions corresponded to a type I to IV pattern.

CONCLUSION

The NBI ability to detect changes in the mucosal microvasculature can be useful for distinguishing nonmalignant from malignant lesions. An internationally accepted NBI-endoscopic classification may contribute to the further definition of the diagnostic validity of this technique.

[Advances in endoscopic diagnosis of dysplasia and carcinoma of the larynx]

To improve the preoperative and intraoperative diagnosis of laryngeal cancer and its precursors, various endoscopic imaging techniques have been developed in recent years. These techniques differ markedly in their specific applications and goals. Precisely distinguishing among normal mucosa, dysplasia and invasive carcinoma with these procedures is necessary. Furthermore, the exact identification of tumor margins should be possible. The long-term goal is the development of optical biopsy. Since so far there have only been small studies regarding the evaluation of the presented methods, it is necessary to establish multi-center trials with large sample sizes to accurately estimate the value of these endoscopic imaging techniques.

Optical and molecular techniques to identify tumor margins within the larynx

Failure to remove tumor cells from the larynx significantly increases the risk of local recurrence following surgical excision. Healthy tissue must be preserved to optimize long-term vocal and swallowing function. It is essential to accurately distinguish between healthy mucosa, dysplasia, and invasive carcinoma. Optical and molecular examining technologies have been developed to improve tumor margin identification in vivo. We aimed to review the efficacy of these technologies. Published articles were identified using MEDLINE, EMBASE, and Cochrane central register of controlled trials (CENTRAL). Randomized clinical trials are required to establish the benefit to patients and cost to the health service of using 5-aminolevulinic acid (ALA)-induced fluorescent imaging, contact endoscopy, and optical coherence tomography (OCT). Furthermore, primary research is required to validate other techniques, such as confocal endomicroscopy and Raman spectroscopy, and to develop their clinical applications in the larynx.

Contact endoscopy as a novel technique in the detection and diagnosis of mucosal lesions in the head and neck: a brief review

Background. There are a variety of described noninvasive optical detection techniques for evaluation of head and neck mucosal lesions. Contact endoscopy is a promising method of in vivo microscopic examination whereby a rigid telescope is placed on a previously dye-stained mucosa allowing evaluation of the superficial cell layers of the epithelium. This technique produces real-time, magnified images of cellular architecture of surface mucosa comparable to histology without the need for biopsy. In this review, we will briefly summarize the efficacy of CE in the detection of precancerous and cancerous mucosal lesions and its potential as a novel technique in early diagnosis, monitoring, and preoperative assessment of mucosal lesions of the head and neck. Methods. PUBMED, MEDLINE, and COCHRANE search revealed five prospective articles on contact endoscopy for the diagnosis of mucosal lesions in the head and neck. Results. The literature search yielded five prospective studies examining contact endoscopy for the diagnosis of benign versus malignant head and neck mucosal lesions. These reported a sensitivity and specificity of 77-100%, specificity of 66-100% and an accuracy of 72-92%. Conclusion. Contact endoscopy is a promising optical technology that may be a useful adjunct in the evaluation and diagnosis of benign and malignant head and neck mucosal lesions. Future prospective randomized double-blind studies of this detection method are required.

Value of autofluorescence bronchoscopy in patients with laryngeal cancer

BACKGROUND

Patients with squamous cell carcinoma of the head and neck constitute a high risk group for synchronous and metachronous tumours.

OBJECTIVE

This study aimed to investigate the usefulness of white light and autofluorescence bronchoscopy in the evaluation of pre-malignant and early neoplastic lesions in patients with laryngeal cancer, who are at high risk of concomitant lung cancer.

METHODS

This prospective, cross-sectional study included 30 patients who had undergone total laryngectomy for squamous cell carcinoma of the larynx. The tracheobronchial system was investigated for the presence of pre-malignant and malignant lesions, using a combination of white light and autofluorescence bronchoscopy. Biopsies were obtained from areas with a pathological appearance, and histopathological studies were performed.

RESULTS

All patients had a permanent tracheostomy. Light and autofluorescence bronchoscopy indicated that the tracheobronchial system was normal in 11 patients. A total of 27 biopsies was taken from the remaining 19 patients, and revealed invasive squamous cell carcinoma in one patient and pre-malignant changes in six.

CONCLUSION

Bronchoscopy is a valuable and practical tool for screening patients at high risk of lung cancer, and requires minimal intervention especially in patients with a permanent tracheostomy. Of the various bronchoscopic techniques becoming available, autofluorescence bronchoscopy shows promise for the detection of pre-invasive malignant changes of the tracheobronchial system in patients previously operated upon for laryngeal cancer.

Early detection in head and neck cancer - current state and future perspectives

Survival and quality of life in head and neck cancer are directly linked to the size of the primary tumor at first detection. In order to achieve substantial gain at these issues, both, primary prevention and secondary prevention, which is early detection of malignant lesions at a small size, have to be improved. So far, there is not only a lack in the necessary infrastructure not only in Germany, but rather worldwide, but additionally the techniques developed so far for early detection have a significance and specificity too low as to warrant safe implementation for screening programs. However, the advancements recently achieved in endoscopy and in quantitative analysis of hypocellular specimens open new perspectives for secondary prevention. Chromoendoscopy and narrow band imaging (NBI) pinpoint suspicious lesions more easily, confocal endomicroscopy and optical coherence tomography obtain optical sections through those lesions, and hyperspectral imaging classifies lesions according to characteristic spectral signatures. These techniques therefore obtain optical biopsies. Once a "bloody" biopsy has been taken, the plethora of parameters that can be quantified objectively has been increased and could be the basis for an objective and quantitative classification of epithelial lesions (multiparametric cytometry, quantitative histology). Finally, cytomics and proteomics approaches, and lab-on-the-chip technology might help to identify patients at high-risk. Sensitivity and specificity of these approaches have to be validated, yet, and some techniques have to be adapted for the specific conditions for early detection of head and neck cancer. On this background it has to be stated that it is still a long way to go until a population based screening for head and neck cancer is available. The recent results of screening for cancer of the prostate and breast highlight the difficulties implemented in such a task.

Fluorescent molecular imaging and dosimetry tools in photodynamic therapy

Measurement of fluorescence and phosphorescence in vivo is readily used to quantify the concentration of specific species that are relevant to photodynamic therapy. However, the tools to make the data quantitatively accurate vary considerably between different applications. Sampling of the signal can be done with point samples, such as specialized fiber probes or from bulk regions with either imaging or sampling, and then in broad region image-guided manner. Each of these methods is described below, the application to imaging photosensitizer uptake is discussed, and developing methods to image molecular responses to therapy are outlined.

Advances in laryngeal imaging

Imaging and image analysis became an important issue in laryngeal diagnostics. Various techniques, such as videostroboscopy, videokymography, digital kymography, or ultrasonography are available and are used in research and clinical practice. This paper reviews recent advances in imaging for laryngeal diagnostics.

[Diagnosis of laryngeal carcinoma]

DIAGNOSTICAL PROBLEMS OF LARYNGEAL CARCINOMA: Carcinoma of the larynx is still a prognostic serious disease associated with high mortality. Survival rates for these tumors vary and depend on the presence of early symptoms, anatomic accessibility and lymphatic supply. Despite advances in therapy and novel surgical and non-surgical approaches, early diagnosis remains the best predictor of survival.

STRATEGY AND NOVEL DIAGNOSTICAL PROCEDURES

This article reviews the diagnosis for laryngeal carcinoma in an effort to heighten the clinical and endoscopic recognition of these lesions, providing also global overview of clinical conventional and recent endoscopic diagnostic tools for squamous cell type of carcinoma of the larynx. Screening of asymptomatic individuals would detect tumors at an early enough stage to patients' benefit.

CONCLUSION

The progress in the elucidation of the molecular genetic changes in these tumors should soon bring novel diagnostic procedures into the clinical practise. The review higlights the important advances of endoscopic, radilogical and molecular methods in detection of the tumor which may help clinicians to diagnose tumors as early as possible. TNM staging, biopsy and histopathological grading remain the gold standard for diagnosis of laryngeal carcinoma. A great number of novel endoscopical methods are only supplementary tools to microlaryngoscopy. Some of the most significant biological markers might be integrated with the evaluation of behavioural factors, clinical and histopathological examinations for a new clinicomolecular approach to laryngeal cancer.

Using the patient's questionnaire data to screen laryngeal disorders

This paper is concerned with soft computing techniques for screening laryngeal disorders based on patient's questionnaire data. By applying the genetic search, the most important questionnaire statements are determined and a support vector machine (SVM) classifier is designed for categorizing the questionnaire data into the healthy, nodular and diffuse classes. To explore the obtained automated decisions, the curvilinear component analysis (CCA) in the space of decisions as well as questionnaire statements is applied. When testing the developed tools on the set of data collected from 180 patients, the classification accuracy of 85.0% was obtained. Bearing in mind the subjective nature of the data, the obtained classification accuracy is rather encouraging. The CCA allows obtaining ordered two-dimensional maps of the data in various spaces and facilitates the exploration of automated decisions provided by the system and determination of relevant groups of patients for various comparisons.

The role of flexible autofluorescence laryngoscopy in the diagnosis of malignant lesions of the larynx

CONCLUSION

Autofluorescent endoscopy (AFE) combined with microlaryngoscopy (MLS) gives a more accurate diagnosis of laryngeal pathology and can be further refined to minimize the need for MLS under general anaesthesia.

OBJECTIVE

The aim of the present study was to evaluate the diagnostic potential and limitations of autofluorescent flexible laryngoscopy in comparison to MLS.

PATIENTS AND METHODS

We examined 40 patients using the Pentax SAFE 1000 system. All patients then underwent direct MLS and biopsy under general anaesthesia. Biopsies were taken from areas that were visually suspicious and then from areas that showed disturbed autofluorescent signals.

RESULTS

The overall sensitivity of AFE for various pathologies was 90.625%, while the sensitivity of MLS was 75%. Combining the findings of AFL and MLS we had a 100% diagnostic yield.

Management of laryngeal dysplasia: a review

Laryngeal dysplasia is a common clinical concern. Despite major advancements in otolaryngology, a significant number of patients with the condition progress to invasive carcinoma. In the recent years, new diagnostic techniques such as autofluorescence and contact endoscopy have been applied to increase the accuracy of the laryngeal biopsies. Moreover, significant efforts have been made to correlate the histopathological appearance of the dysplastic samples to their clinical course. So far, a wide range of therapeutic strategies for different grades of dysplasia has been suggested by authors; however, there is a lack of outcome reviews. In the current review, the outcome of different therapeutic strategies for severe dysplasia and carcinoma in situ has been compared with statistical analysis. The paper also summarises the current knowledge of the alternative management methods as well as current areas of research in the chemoprevention of the condition. (1) Significant efforts have been made to develop new techniques to improve the accuracy of microlaryngoscopic assessment of laryngeal premalignancy. Comparative studies are required using microlaryngoscopy against the new techniques to evaluate their clinical utility. (2) The meta-analysis suggests a better local control rate with radiotherapy compared to other standard methods of management of dysplasia; however, functional impairment and complications associated with each of the standard treatments should be further evaluated.

Biophotonic and Other Physical Methods for Characterizing Oral Mucosa

This article discusses biophotonic and other physical methods for characterizing oral mucosa.

Formulation and implementation of a phase-resolved fluorescence technique for latent-fingerprint imaging: theoretical and experimental analysis

A theoretical and experimental study of the imaging of latent fingerprints by a phase-resolved fluorescence technique along with associated signal-processing analysis is described. The system configuration is optimized by incorporation of a novel approach of homodyne-assisted even-step phase shifting in a signal-processing concept. The excitation laser source and gain of the detection device, which are modulated at megahertz frequency followed by sensitive signal-processing concepts, are employed to separate the fingerprint fluorescence from background fluorescence. Experiments are carried out with fingerprints deposited upon different types of substrate surfaces. Later, a quantitative image-quality assessment is carried out, which confirms the improvement in the quality of the phase-resolved fingerprint image. Imaging of older fingerprints with better contrast is also carried out with the proposed novel technique.

Management of advanced premalignant laryngeal lesions

PURPOSE OF REVIEW

Laryngeal carcinogenesis is a multistep process with premalignant lesions progressing to invasive carcinoma over a period of years. The approach to these advanced premalignant lesions has always been early diagnosis and treatment to prevent further progression. Unfortunately, with the current means of diagnosis and a lack of consensus regarding treatment of these lesions, the incidence of advanced laryngeal malignancies continues to rise. The purpose of this article is to review the most recent contributions to the literature regarding diagnosis and management of advanced laryngeal premalignant lesions.

RECENT FINDINGS

The current literature focuses on several new diagnostic procedures to improve early detection of high-risk laryngeal lesions. These procedures include autofluorescence endoscopy, compact endoscopy, and topical 5-aminolevulinic acid. One large long-term study suggests an aggressive surgical approach in the treatment of advanced laryngeal premalignancies to decrease the incidence of malignant transformation. The preliminary results of chemoprevention trials as well as potential new biomarkers are discussed.

SUMMARY

There are several new promising procedures that may have an impact on the early diagnosis of laryngeal precursor lesions. In addition, we are gaining knowledge about the molecular events occurring along the continuum of laryngeal carcinogenesis. This will hopefully allow the identification of additional biomarkers and future targets for chemoprevention.

Panendoscopy and synchronous second primary tumors in head and neck cancer patients

Endoscopy techniques are used to diagnose and to determine the extent and exact location of malignancies in the head and neck region, bronchial tree and esophagus. Panendoscopy is used to find the primary tumor in the case of metastatic disease from unknown primaries or to detect a simultaneous second primary tumor at the time of diagnosis of a malignancy in the upper aerodigestive tract (UADT). The value of panendoscopy has been debated lately because of the relatively small proportion of malignant findings and because of the lack of convincing data concerning its effect on survival rates. However, despite the relatively low proportion of positive findings, their significance is often crucial for the individual patient. The significant number of late metachronous, second primaries, especially in the lungs, also emphasizes the importance of follow-up endoscopies. This study consists of 203 consecutive patients with squamous cell cancer (SCC) of the upper aerodigestive tract who underwent panendoscopy in Turku University Central Hospital as part of the initial diagnostic workup from 1992-1999. Eight patients with synchronous second primaries were found to represent a prevalence of 3.9%, and in addition, 19 patients with metachronous tumors were diagnosed. In the case reports we illustrate the importance of some of these findings.

Investigation of normal and malignant laryngeal tissue by autofluorescence imaging technique

OBJECTIVE

During oncogenesis significant changes in tissue properties occur that result in alteration of fluorescence characteristics of the tissue. The differences in autofluorescence between normal and malignant tissues offer new possibilities in detecting epithelial pathological lesions.

AIM

The aim of our study was to determine the usefulness of autofluorescence technique in diagnostic of laryngeal tumors.

MATERIAL AND METHODS

Fluorescence in larynxes from 10 laryngectomized cancer patients was induced by excitation light at 360-450 nm wavelength. As a light source, mercury lamp and laser (404 nm) were used. The CCD camera captured the fluorescent light emitted. Normal epithelium and cancer tissue were also analyzed on fluorescence microscopy.

RESULTS

Laryngeal carcinoma tissues when excited with ultraviolet or blue light generate attenuated or absent autofluorescence in the green light band compare with normal epithelium where strong signal around 505 nm was detected. Average value of maximal autofluorescence intensities was 26.2V (range 18-35) and 4.4V (range 2-8) in healthy and cancerously changed mucosa respectively. Spectral analysis revealed that autofluorescence signal from unchanged mucosa (around 505 nm) was significantly higher compared to cancer tissue (P=0.005).

CONCLUSIONS

It seems that autofluorescence imaging may be a supplementary tool in diagnosis of laryngeal tumors.

Luminescent lanthanide chelate contrast agents and detection of lesions in the hamster oral cancer model

Lanthanide chelates are a somewhat unique class of molecules that have proven to be useful in the biomedical field due to their extremely large Stokes' shift and long fluorescent lifetimes. The ability of these molecules to produce fluorescence in the low- or zero-back-ground regime makes this class of molecules excellent candidates for use as contrast agents for a wide variety of applications in biological settings. Here we present the preparation, spectroscopic characterization, and application of a new terbium chelate contrast agent, based on the 1,4,7,10-tetraazacyclododecane macrocycle (cyclen), for detection of early-stage malignant lesions in the Syrian hamster cheek pouch. Tb-P(CTMB) delivers bright blue-green luminescence when excited with low photon fluxes of UV light. As a pilot study, the DMBA-treated Golden Hamster Cheek pouch epithelial cancer model was employed and Tb-P(CTMB) was used as a topical agent for the visual detection of diseased tissue. In this preliminary study the agent tended to associate with early-stage malignant lesions, suggesting that Tb-P(CTMB) could be used as a contrast agent to aid in identifying early-stage oral cancer lesions.

Autofluorescent diagnostics in laryngeal pathology

Autofluorescent diagnostics are based on the ability of oxidized flavin mononucleotide (FMN) in normal cells to emit green fluorescence when exposed to blue light. Neoplastic cells have significantly lower concentrations of FMN and do not emit green fluorescence. Autofluorescent endoscopy is designed for early, accurate and minimally invasive diagnostics for laryngeal pathology. This procedure has the ability to give information about the nature of laryngeal lesions without the devastation of tissue and has important advantages over standard biopsy. In our investigation we used the System of AutoFluorescent Endoscopy (SAFE 1000) designed by Pentax. We examined 38 patients using the SAFE 1000 system, and then all of the patients underwent laryngomicroscopy (LMS). In LMS, a biopsy was taken, and the diagnostic sensitivity of these two methods was compared according to the pathohistologic diagnosis. For statistical evaluation we used Fisher's exact test. We found that autofluorescent endoscopy has greater sensitivity in the detection of precancerous and malignant conditions in the larynx than standard laryngomicroscopy. We believe that autofluorescent endoscopy in addition to laryngomicroscopy gives a more accurate diagnosis of laryngeal pathology than laryngomicroscopy alone.

Autofluorescence endoscopy in the diagnosis of early laryngeal cancer and its precursor lesions

OBJECTIVES

Because early detection and preoperative assessment of laryngeal cancer and its precursor lesions are essential for curative and function-preserving surgical treatment, autofluorescence endoscopy has been developed to gain more information about the biologic character of these lesions. The aim of the present study is to investigate a high, representative number of patients and to evaluate the diagnostic potential and the limitations of this method.

METHODS

In a prospective study, 127 patients were investigated during microlaryngoscopy. A total of 111 patients were suspected of having precancerous or cancerous lesions, 12 had benign lesions, and 4 patients had normal epithelium. Autofluorescence was induced by filtered blue light (380-460 nm) of a xenon short arc lamp and processed by a CCD camera system (D-light-AF system; Storz, Tuttlingen, Germany). Autofluorescence endoscopic images were immediately assessed for diagnosis, correlated to the dysplasia grading system and compared with the histopathologic findings.

RESULTS

Normal laryngeal mucosa displayed a typical green fluorescence signal. Moderate and high epithelial dysplasia, carcinoma in situ, and invasive carcinoma showed a diminished green fluorescence. False-negative results (n = 2) were the result of extreme hyperkeratosis. False positive cases (n = 8) either showed mild dysplasia with inflammatory reactions or scarring of the vocal folds. In 105 of 111 cases (94.6%), we found concordant results (sensitivity, 97.3%; specificity, 83.8%).

CONCLUSION

Autofluorescence endoscopy facilitates the detection and delineation of precancerous lesions, carcinoma in situ, and microinvasive cancer of the larynx more accurately than clinical observation alone. Scarring, marked hyperkeratosis, and inflammation can limit the predictive value of the method.

A comparative study of normal inspection, autofluorescence and 5-ALA-induced PPIX fluorescence for oral cancer diagnosis

Fluorescence diagnosis aims to improve the management of oral cancer via early detection of the malignant lesions and better delimitation of the tumor margins. This paper presents a comparative study of normal inspection, combined fluorescence diagnosis (CFD) and its 2 main components, autofluorescence and 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PPIX) fluorescence. Biopsy-controlled fluorescence imaging and spectral analysis were performed on a total of 85 patients with suspected or histologically proven oral carcinoma both before and after topical administration of 5-ALA (200 mg 5-ALA dissolved in 50 ml of H(2)0). Fluorescence excitation was accomplished using filtered light of a xenon short arc lamp (lambda = 375-440 nm). As for CFD, a "streetlight" contrast (red to green) was readily found between malignant and healthy tissue on the acquired images. In terms of tumor localization and delimitation properties, CFD was clearly favorable over either normal inspection or its 2 components in fluorescence imaging. The performance of CFD was found to be impeded by tumor keratinization but to be independent of either tumor staging, grading or localization. In spectral analysis, cancerous tissue showed significantly higher PPIX fluorescence intensities and lower autofluorescence intensities than normal mucosa. There is a great potential for CFD in early detection of oral neoplasms and exact delimitation of the tumors' superficial margins and an advantage over white light inspection and each of its 2 main components. The method is noninvasive, safe and easily reproducible.

Autofluorescence endoscopy: feasibility of detection of GI neoplasms unapparent to white light endoscopy with an evolving technology

BACKGROUND

Case studies are presented of fluorescence endoscopy in the upper and lower GI tract to illustrate the ability to detect early-stage lesions that were not observable with white light endoscopy or those in which the assessment of the stage or extension of the lesion were equivocal.

METHODS

A new fluorescence imaging system was used in which blue light excites the naturally-occurring fluorescence of tissues (autofluorescence). The system produces real-time, false-color images that combine green and red fluorescence intensities. In general, abnormal lesions are seen to have an increase in the red-to-green fluorescence intensity compared with surrounding tissue. This system was evaluated in patients at 4 participating institutions, concurrently with standard white light endoscopy, with or without dye staining.

RESULTS

Selected cases are presented in which fluorescence imaging identified specific lesions including focal high-grade dysplasia in Barrett's mucosa, signet ring carcinoma of the stomach, and flat adenoma in the colon.

CONCLUSIONS

The capability of autofluorescence endoscopy to detect the presence and extent of occult malignant and premalignant GI lesions has been demonstrated. The future development and evaluation of this technology are discussed.