Vital staining with iodine solution in delineating the border of oral dysplastic lesions

Histopathological characteristics of an oral epithelial dysplasia model in rats showing a negative reaction to fluorescence visualization

Vital staining has long been used to delineate the horizontal margins for resection in oral squamous cell carcinoma and in oral epithelial dysplasia (OED). In recent years, fluorescence visualization (FV), a simple and non-invasive technique, has been used to identify resection margins. However, FV occasionally fails to detect OED. The purpose of this study is to investigate why lesions are not detected using FV and to evaluate their histopathology. The tongues of an OED rat model were examined using FV, and the obtained images were objectively evaluated by quantifying the fluorescence intensity (FI) through image analysis software. Hematoxylin-eosin and immunohistochemical staining were performed to characterize FV loss (FVL) and FV retention (FVR). Some OED lesions were recognized through FVR. In FVL, the CD31-positive rate was higher than in FVR, and the CD31-positive rate negatively correlated with FI. In contrast, a positive correlation was observed between FI and the thickness of the epithelial layer. Multiple regression analysis suggested that the CD31-positivity rate and epithelial thickness may be involved in FI. These findings suggest that the accuracy of FV detection is influenced by multiple factors, including angiogenesis and epithelial layer thickness. Therefore, a combination of various testing methods should be considered.

Clinical value of entire-circumferential intraoperative frozen section analysis for the complete resection of superficial squamous cell carcinoma of the tongue

OBJECTIVES

We aimed to evaluate the clinical value of an entire-circumferential intraoperative frozen section analysis (e-IFSA) for the complete resection of superficial squamous cell carcinoma (SCC) of the tongue.

MATERIALS AND METHODS

A total 276 specimens from 51 patients with pT1-2, N0, mucosal or submucosal invasion SCC were analyzed to evaluate the diagnostic accuracy of the e-IFSA and the added value of the e-IFSA to iodine staining. The e-IFSA results were compared with the final histologic results obtained using permanent sections. All specimens for the e-IFSA were taken over the entire circumference 5 mm outside from the iodine unstained areas. The outline of the main resected specimen after taking these outer mucosal specimens were defined as the surgical margins determined by iodine staining alone.

RESULTS

The e-IFSA results were in excellent agreement with final histological results (Cohen's kappa value: 0.85) and the e-IFSA showed high sensitivity (100%) and high negative predictive value (100%). The actual complete resection rate with an e-IFSA was 100% (51/51), and no patient required additional resection after surgery. In contrast, 10/51 patients (20%) patients showed residual atypical mucosal epithelium at or beyond the margin determined by iodine staining alone; this difference was statistically significant (P = 0.002). The 5-year local control rate and 5-year overall survival rate after this procedure were both 100%.

CONCLUSION

An e-IFSA has additional value when performed in conjunction with iodine staining. An e-IFSA would be useful for achieving complete resection of superficial SCC of the tongue.

Diagnostic efficiency of methylene blue and lugol's iodine double staining method in oral leukoplakia in detecting dysplasia

Objectives

Early detection of dysplasia in oral potentially malignant disorders (PMD) might facilitate screening for possible subsequent malignant transformation. Vital staining is a non-invasive clinical adjunct used for determining the biopsy site, which facilitates early detection of dysplastic changes in PMD. Some authors suggested that double staining method has superior results over staining with a single dye.

Aim

The aim of the study was to evaluate the accuracy of in vivo staining with methylene blue (MB) and Lugol's iodine (LI) double staining method in comparison with MB staining alone.

Materials and Methods

Fifty patients of oral leukoplakia were recruited for the study. After obtaining written informed consent from the patients, the lesions were stained consecutively with 5% MB and 3% LI. The pattern of dye retention of MB alone, followed by MB and LI was noted. Incisional biopsy from the lesion was taken based on the retention of MB and the absence of staining of LI or by clinical judgement in case both stains were not retained. The clinical uptake of the stains was correlated with the degree of dysplasia on histopathological examination.

Results

Out of 50 subjects, MB was retained in 47 cases (94%), while 3 cases (6%) failed to retain the dye. However, out of 47 cases, 20 cases had dark blue stain and were considered as MB positive, while the rest 27 cases had pale blue stain and were considered to be negative for MB staining. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy (DA) of MB staining were 57.82%, 100%, 100%, 26.53% and 46%, respectively. After applying both stains, i.e., double staining method, the outline of the lesion was better defined. Out of 50 PMD cases, 3 patients retained only LI and showed no dysplasia. Out of 47 cases which showed dysplasia, 27 cases showed pale blue retention of MB (-) and also were negative for LI. The rest 20 cases were positive for MB but negative for LI. The sensitivity, specificity, PPV and NPV with double staining technique were 100%.

Conclusion

The accuracy and reliability of double staining method was superior to MB staining.

Clinical Relevance

Increased accuracy of double staining method aids in better detection of dysplasia and is of great help to the clinician in deciding the nature of PMD in question.

Usefulness of fluorescence visualization-guided surgery for early-stage tongue squamous cell carcinoma compared to iodine vital staining

BACKGROUND

In the most cases of oral squamous cell carcinoma (OSCC), oral epithelial dysplasia (OED) is found adjacent to the primary tumor. The delineation of surgical margins for OSCC is critical to minimize the risk for local recurrence. The aim of this study is to demonstrate that the fluorescence visualization (FV)- device can delineated the lesion visualizes OED of adjacent primary tumors by histopathologically comparison to conventional iodine vital staining.

MATERIAL AND METHODS

The study involved 40 patients with superficial tongue squamous cell carcinoma treated from July 2016 to July 2018 at the Oral Cancer Center, Tokyo Dental College.

RESULTS

Cytokeratin 13 (CK13) expression rate in the area of fluorescence visualization loss (FVL) was significantly lower than that in the area of fluorescence visualization retention (FVR). In addition, CK17, Ki-67, and p53 expression rates were significantly higher in FVL than FVR. There was no significant difference in the delineation rate or area between FVL and iodine-unstained area. High-grade dysplasia was observed most frequently at the FV and iodine-unstained boundary, but no significant pathological differences were found.

CONCLUSION

We strongly suggest the FV-guided surgery is a useful method for accurate resection in early-stage tongue squamous cell carcinoma.

Current Practice and Emerging Molecular Imaging Technologies in Oral Cancer Screening

Oral cancer is one of the most common cancers globally. Survival rates for patients are directly correlated with stage of diagnosis; despite this knowledge, 60% of individuals are presenting with late-stage disease. Currently, the initial evaluation of a questionable lesion is performed by a conventional visual examination with white light. If a lesion is deemed suspicious, a biopsy is taken for diagnosis. However, not all lesions present suspicious under visual white light examination, and there is limited specificity in differentiating between benign and malignant transformations. Several vital dyes, light-based detection systems, and cytology evaluation methods have been formulated to aid in the visualization process, but their lack of specific biomarkers resulted in high false-positive rates and thus limits their reliability as screening and guidance tools. In this review, we will analyze the current methodologies and demonstrate the need for specific intraoral imaging agents to aid in screening and diagnosis to identify patients earlier. Several novel molecular imaging agents will be presented as, by result of their molecular targeting, they aim to have high specificity for tumor pathways and can support in identifying dysplastic/cancerous lesions and guiding visualization of biopsy sites. Imaging agents that are easy to use, inexpensive, noninvasive, and specific can be utilized to increase the number of patients who are screened and monitored in a variety of different environments, with the ultimate goal of increasing early detection.

Clinical Application of the IllumiScan Fluorescence Visualization Device in Detecting Oral Mucosal Lesions

Objective: Fluorescence visualization devices are screening devices that can be used to examine lesions of the oral mucosa non-invasively. We observed oral squamous cell carcinoma (OSCC) and leukoplakia using the IllumiScan (Shofu, Kyoto, Japan) fluorescence visualization device and examined its usefulness and characteristics.

Methods: We investigated 31 OSCC and nine leukoplakia in patients who were examined using the IllumiScan and treated in our department from January 2017 to February 2018. Images taken with the IllumiScan were analyzed using image analysis software. We also examined the lesions using narrowband imaging (NBI). Additionally, the IllumiScan and NBI images and the non-stained areas of iodine staining method (IOM) were visually evaluated.

Results: The average luminance of OSCC in the keratinized mucosa was significantly lower than that of OSCC in non-keratinized mucosa. The average luminance of OSCC was significantly lower than that of leukoplakia. Even in keratinized mucosa where IOM is impossible to use, the OSCC lesion exhibited fluorescence visualization loss.

Conclusion: The application of the fluorescence visualization device to the oral mucosa may be useful for distinguishing between cancer and normal areas and can be used to detect OSCC in the keratinized mucosa. The use of the IllumiScan in combination with other conventional screening methods may lead to a better diagnosis.

Difference in glycogen metabolism (glycogen synthesis and glycolysis) between normal and dysplastic/malignant oral epithelium

BACKGROUND

The purpose of this study was to investigate a difference in glycogen metabolism (glycogen synthesis and glycolysis) between the iodine stained (normal non-keartinized) and the unstained (dysplasctic/malignant) oral epithelium.

METHODS

Twenty-one frozen tissue samples of iodine-stained and unstained mucosal tissue were obtained from 21 OSCC patients. Serial frozen sections were cut and examined with the hematoxylin-eosin and periodic acid-Schiff methods and immunohistochemical (IHC) staining for Ki67, P53, molecules associated with glycogenesis (i.e., glycogen synthase (GS) and phospho-glycogen synthase (PGS)), and molecules associated with glycogenolysis (i.e., glycogen phosphorylase isoenzyme BB (GPBB) examine the glycogen metabolism in OSCC. Additionally, in vitro study, the expression levels of GS and GPBB in the cultured cells were analyzed by immunofluorescent staining, Western blot analysis, and the real-time quantitative polymerase chain reaction (PCR).

RESULTS

There was no significant difference in GS and PGS immunoactivity between iodine stained and unstained area. On the other hand, significantly greater GPBB immunoreactivity was observed in the basal and parabasal layers of iodine-unstained epithelium, where higher positivity for p53 and Ki67 was also showed. Additionally, western blot analysis, immunofluorescent staining, and real-time quantitative PCR revealed that the oral squamous cancer cells exhibited greater expression of GPBB than normal epithelial cells.

CONCLUSIONS

The results of this study showed that GPBB expression, which resulted in up-regulation of glycogenolysis, is enhanced in oral dysplastic/malignant epithelium compared with non-keartinized normal epithelium, in spite of the fact that glycogenesis continues in both of them. Premalignant and malignant epithelial cells consume greater quantities of energy due to their increased proliferation, and hence, exhaust their glycogen stores, which resulting in negative stain reaction with iodine solution.

Clinical relevance of the utilization of vital Lugol's iodine staining in detection and diagnosis of oral cancer and dysplasia

OBJECTIVES

The aim of this study is to assess the clinical relevance of the utilization of vital Lugol's iodine staining in detection of oral cancer and dysplastic lesions as well as demarcation of the extent of these lesions.

MATERIALS AND METHODS

A prospective, cross-sectional, hospital-based study was performed in Khartoum Teaching Dental Hospital, Sudan. Suspicious oral epithelial lesions indicating incisional biopsy were stained with 10 % Lugol's iodine solution and were clinically designated as "negative" for dysplasia or neoplasia when no unstained lesion (USL) area was observed, or as "positive" when a USL area is observed. Incisional biopsies involving both the unstained portion and the stained portion were obtained and histologically evaluated for definitive diagnosis.

RESULTS

Forty-five biopsies were obtained from 28 patients. Histopathological examination of the specimens confirmed some degree of dysplasia or neoplasia in all clinically positive specimens with oral squamous cell carcinoma (OSCC) being the most common definitive diagnosis (17 patients, 60.7 %). Clinical relevance level of vital Lugol's iodine staining in detecting oral cancer and dysplasia was found to be 90.9 % (SE = 0.05, P = 0.05).

CONCLUSION

The findings of this study showed that Lugol's iodine is an easy, safe, and effective method of visualizing oral epithelial lesions and differentiating epithelial carcinoma and dysplasia from other benign mucosal lesions. Despite certain limitations, its use is of great value in detection and diagnosis of oral cancer and dysplasia.

CLINICAL RELEVANCE

Lugol's iodine staining can effectively be used in detection of the dysplastic and malignant superficial lesions of the oral epithelium.

Iodine penetration and glycogen distribution in vital staining of oral mucosa with iodine solution

OBJECTIVE

To assess and compare iodine penetration and glycogen distribution in a vital staining of oral mucosa with iodine solution.

STUDY DESIGN

Twenty samples were obtained including both iodine-stained and -unstained mucosa. Intraepithelial iodine was examined using frozen sections. Glycogen distribution was assessed by periodic acid-Schiff staining and transmission electron microscopy.

RESULTS

Iodine accumulation was observed mainly superficially and in the upper and middle thirds of prickle cell layers, with glycogen in almost the whole epithelium except for the para- and basal cell layers. The pattern of iodine and glycogen distribution was classified into 3 types (full-, surround-, and scatter-type). The iodine color was mainly derived from the cells with full- and surround-type distributed glycogen in the upper half of the oral epithelium.

CONCLUSIONS

The results of this study suggested that iodine penetrated into nonkeratinized oral epithelium and reacted mainly with intraepithelial glycogen homogeneously distributed in the cytoplasm.

Effectiveness of vital staining with iodine solution in reducing local recurrence after resection of dysplastic or malignant oral mucosa

The purpose of this retrospective study was to assess the effect of vital staining with iodine solution in reducing local recurrence after resection of dysplastic or malignant oral mucosa. The historical control group had dysplastic or malignant mucosal lesions resected solely on the evidence of direct inspection and palpation. In the vital staining group tissue was resected only after vital staining with iodine solution. Seven of 25 patients in the conventional group developed recurrent dysplastic or cancerous oral mucosa around the primary site, while no patient among 23 reported recurrence in the vital staining group (p<0.01). Kaplan-Meier assessment showed that the 5-year primary control rate was 100% in the vital staining group and 75% in the conventional group. Although this retrospective study has some limitations, the results suggest that vital staining with iodine may be useful in reducing the incidence of recurrence of dysplastic or cancerous epithelium at a primary site. Further well-controlled study is essential.

Oral premalignant lesions: from the pathological viewpoint

Under the widely used World Health Organization (WHO) classification for the pathological diagnosis of oral premalignant lesions, dysplasia, which is graded as mild, moderate or severe, and carcinoma in situ (CIS), which is a non-invasive carcinoma, are classified as precursor lesions of oral squamous cell carcinoma. Since the first edition (Wahi et al. International histological classification of tumours no. 4, WHO, Geneva, 1971), the criterion for CIS--that all epithelial layers are replaced by atypical cells--has remained unchanged. However, this dysplasia-carcinoma sequence theory was introduced from the viewpoint of pathological changes in the uterine cervix: in contrast, almost all premalignant lesions and CIS of the oral mucosa show superficial maturation and differentiation. Based on this recognition, the squamous intraepithelial neoplasia (SIN) classification and Ljubljana classification were included in WHO's latest edition published in 2005. Although the WHO classification is commonly used in Japan, recent developments in oral oncology have promoted modifications of the classification used in this country. In 2005, the Working Group of the Japan Society for Oral Tumours advocated iodine staining and proposed a modified SIN system, and in 2007, the Working Committee of the Japanese Society for Oral Pathology (JSOP) reported a new CIS (JSOP) definition that included differentiated-type CIS. In 2010, based on these studies, a new entity--oral intraepithelial neoplasia (OIN)--was included in the first edition of General Rules for Clinical and Pathological Studies on Oral Cancer. In this review, we focus on the OIN/CIS (JSOP) new classification of premalignant lesions in oral mucosa, which further advances the concept of SIN.

Use of Lugol's iodine in the resection of oral and oropharyngeal squamous cell carcinoma

We evaluated the use of Lugol's iodine in achieving surgical margins free from dysplasia, carcinoma in situ, and invasive carcinoma by an observational study of two series of 50 consecutive patients having resection of oral and oropharyngeal squamous cell carcinoma (SCC) between November 2004 and March 2007. The standard group had resection of the primary tumour with a macroscopic 1cm margin and removal of adjacent visibly abnormal mucosa. The Lugol's iodine group had identical treatment with resection of any adjacent mucosa that did not stain after the application of Lugol's iodine (where this was feasible). In the standard group 16 patients (32%) had dysplasia, carcinoma in situ, or invasive SCC at a surgical margin. In the Lugol's iodine group two patients (4%) had dysplasia or carcinoma in situ; none had invasive SCC. Lugol's iodine is a simple, inexpensive, and apparently effective means of reducing the likelihood of unsatisfactory surgical margins in the resection of oral and oropharyngeal SCC.

A pilot case control study on the efficacy of acetic acid wash and chemiluminescent illumination (ViziLite) in the visualisation of oral mucosal white lesions

Conventional screening practice for oral lesions involves visual scrutiny of the oral tissues with the naked eye under projected incandescent or halogen illumination. Visualisation is the principal strategy used to assess patients' lesions at risk for malignant transformation; hence, any procedure which highlights such lesions should aid the clinician. The aim of this pilot study was to examine the efficacy of acetic acid wash and chemiluminescent light (ViziLite) in enhancing visualisation of oral mucosal white lesions, and its ability to highlight malignant and potentially malignant lesions. Fifty five patients referred for assessment of an oral white lesion, were prospectively screened with ViziLite, and an incisional scalpel biopsy performed for a definitive diagnosis. The size, location, ease of visibility, border distinctness, and presence of satellite lesions were recorded. The ViziLite tool enhanced intra-oral visualisation of 26 white lesions. Indeed, all lesions appeared "aceto-white", regardless of the definitive diagnosis. Examination of the oral tissues with ViziLite illumination did not change the provisional diagnosis, nor alter the biopsy site. ViziLite illumination does not discriminate between keratotic, inflammatory, malignant or potentially malignant oral mucosal white lesions and thus, a high index of suspicion, expert clinical judgment, and scalpel biopsy are still essential for proper patient care.

Intraoperative digital microscopic assessment of the deep surgical margins in oral carcinoma surgery: a preliminary report

BACKGROUND

This study assessed the possible ability of intraoperative digital microscopic analysis to control the deep surgical margin in oral carcinoma surgery.

METHODS

A vertical section of a surgical specimen was taken from the central part of the resected tumor. The section was assessed using a digital microscope. The results of digital microscopic analysis were compared with the corresponding results of the conventional histopathologic assessment.

RESULTS

The method was accurate in 10 of the 12 patients (83%) in evaluating the closest deep surgical margin. There was no significant difference in the tumor-margin distance between the digital microscopic and the histopathologic assessments in these 10 patients (Wilcoxon signed-rank test, P > .13).

CONCLUSIONS

The digital microscopic examination was useful in controlling deep surgical margins and selecting the nearest margin for additional frozen section analysis. Additional methods that could clarify the difference between the tumor and fibrous tissue are necessary.

Fluorescence spectroscopy combined with 5-aminolevulinic acid-induced protoporphyrin IX fluorescence in detecting oral premalignancy

BACKGROUND

Early detection of premalignant/malignant lesions in the oral cavity can certainly improve the patient's prognosis. This study presents fluorescence imaging with the topical application of 5-aminolevulinic as a way to improve detection of various oral tissue pathologies. This procedure depends mainly on comparing the intensity of red and green fluorescence emitted from tissues during examination.

MATERIALS AND METHODS

Seventy-one patients who presented with clinically suspicious oral leukoplakia were recruited for this study. Each of the patients was required to have 5-aminolevulinic acid in the form of mouth rinse prior to fluorescence imaging. Following this a surgical biopsy was acquired from the exact examination site. The results of the fluorescence spectroscopy have been compared with histopathology.

RESULTS

A Student's t-test was applied to test the viability of the ratio between red and green fluorescence. The red-to-green ratio was found to increase significantly when the lesion was identified as dysplastic or carcinoma in situ. By applying a threshold line to discriminate between normal and dysplastic lesions; a sensitivity of 83-90% and specificity of 79-89% were obtained.

CONCLUSION

Fluorescence spectroscopy combined with 5-aminolevulinic acid-induced protoporphyrin IX was found as a valuable tool in the diagnosis of oral premalignancy. This technique offers the potential to be advantageous over other non-optical techniques in terms of providing real-time diagnosis, in situ monitoring, cost effectiveness and more tolerated by patient compared to surgical biopsy.

Biophotonic and Other Physical Methods for Characterizing Oral Mucosa

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

The use of digitized endoscopic imaging of 5-ALA-induced PPIX fluorescence to detect and diagnose oral premalignant and malignant lesions in vivo

5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PPIX) fluorescence has shown an outstanding sensitivity for the assessment of oral lesions, but its application was hampered by low specificity due to the high false-positive rates. The purpose of our study was to explore the feasibility of quantifying PPIX fluorescence images to improve the diagnostic specificity for detecting early oral lesions in vivo. A digitized 5-ALA-mediated endoscopic imaging system was utilized to acquire PPIX fluorescence images from in vivo oral tissues. Forty-nine patients (118 biopsies) with known or suspected premalignant or malignant oral lesions were recruited for ALA-PPIX fluorescence endoscopic imaging. The red and blue channels of PPIX fluorescence images were digitized and stored for fluorescence quantification. The red-to-blue intensity ratios were calculated from the fluorescence images to correlate with histologic findings of the biopsies. The results showed that normal oral mucosa exhibited blue color of the back-scattered excitation light in the fluorescence images, whereas the suspicious lesions displayed bright reddish fluorescence. Applying the red-to-blue intensity ratio (I(R)/I(B)) as a diagnostic algorithm yielded a sensitivity of 92% and 98%, and specificity of 96% and 96%, for separating benign tissue from dysplasia, and cancer tissue, respectively, and a sensitivity and specificity of 98% and 92%, respectively, for differentiating cancer tissue from dysplasia in the oral cavity. Our study demonstrates that quantifying ALA-PPIX fluorescence endoscopic images associated with the red-to-blue intensity ratio as a diagnostic algorithm can provide good differentiation between the different stages of oral premalignancy and malignancy (p<0.0001, unpaired 2-sided Student's t-test), and thus has a potential to significantly improve the noninvasive diagnosis and evaluation of early oral neoplasia in vivo.

Quantification of telomerase activity of regions unstained with iodine solution that surround oral squamous cell carcinoma

The aim of this study was to analyze the iodine-unstained region expanding around oral squamous cell carcinoma (SCC) by quantification of telomerase activity. The epithelial dysplasia often observed around SCC is considered to cause local recurrence or a second primary cancer. However these areas are hard to distinguish from normal mucosa. To clear the border of the expanding epithelial dysplasia around SCC, we stained with 3% iodine solution, and then decided the surgical margin. We measured quantification of telomerase activity in tumor, in epithelial dysplasia, and also in normal epithelium. Thirty-three primary cases of oral SCC which have iodine-unstained region around lesions were investigated. Fluorescense-based TRAP was applied to obtain quantification of telomerase activity. We obtained the following results: histological examination confirmed that every patient's unstained region consisted of various degrees of epithelial dysplasia. The quantified telomerase activities for squamous cell carcinoma, epithelial dysplasia and normal epithelium were 53.9, 39.6 and 2.7 U/microgP, respectively, and there was a significant difference between carcinoma and normal areas, and between dysplasia and normal epithelium. Therefore, these findings suggest that the areas of epithelial dysplasia unstained by iodine consist of cells that are nearly cancerous and excessively proliferative, and that epithelial dysplasia around SCC should be resected together with the tumor. Vital staining with iodine is useful for identifying epithelial dysplasia around SCC.

Cell proliferation and tumour suppressor gene expression in iodine unstained area surrounding oral squamous cell carcinoma

The purpose of this study was to investigate the relationship between epithelial dysplasia unstained with iodine and the expression of proliferating cell nuclear antigen (PCNA) and/or tumour suppressor gene (p53) and the existence of glycogen. Thirty cases of squamous cell carcinomas arising from the buccal mucosa and floor of the mouth were examined. Iodine unstained areas were diagnosed histopathologically as mild, moderate or severe epithelial dysplasia. Normal oral mucosa stained with iodine was used as a control group. There was no histochemical difference in the distribution or ratio of PAS-positive cells between the control and the mild epithelial dysplasia groups, however PAS stained areas of the moderate and the severe dysplasia groups were significantly decreased. Ultrastructurally, glycogen granules were not recognized in the moderate or severe dysplastic epithelia. Immunoreactive ratios of PCNA and p53 in the moderate and severe dysplastic groups were significantly higher than those of the control and the mild dysplasia groups. The positive ratio of PCNA was higher than that of p53, although the immunostaining patterns of PCNA- and p53-positive cells were quite similar. These results suggest that mild dysplastic epithelia that are stained with iodine may be in the category of normal epithelia, whereas both moderate and severe dysplasia that are un-stained with iodine may be suspected of malignant lesions.

Detection of squamous cell carcinomas and pre-cancerous lesions in the oral cavity by quantification of 5-aminolevulinic acid induced fluorescence endoscopic images

BACKGROUND AND OBJECTIVES

Studies of 5-aminolevulinic acid-induced protoporphyrin IX fluorescence have shown a sensitivity of 95-100% for oral cancer diagnosis, but the specificity is only about 50-60%. Here, we explore the applicability of quantifying PPIX fluorescence images to improve the diagnostic specificity and detect early oral lesions.

STUDY DESIGN/MATERIALS AND METHODS

PPIX Fluorescence endoscopy and imaging were performed on 28 patients with a known or suspected premalignant or malignant oral cavity lesion. A total of 70 biopsies were taken from the tissue sites imaged for histological analysis. The red-to-blue and red-to-green intensity ratios were calculated from the fluorescence images to correlate with histology.

RESULTS

Suspicious lesions display bright reddish fluorescence, while normal mucosas exhibit blue color background in the fluorescence images. The red-to-blue and red-to-green intensity ratios of malignant tissues are larger than those of benign tissues. Combining the two ratio diagnostic algorithms yields a sensitivity and specificity of 95% and 97%, respectively, exceeding each diagnostic algorithm alone for discriminating malignant tissue from benign tissue.

CONCLUSIONS

Quantifying PPIX fluorescence endoscopic images combined with the ratio diagnostic algorithms developed in this study has the potential to significantly improve the noninvasive diagnosis of oral cavity lesions in vivo.

Oral cancer research with an emphasis on genomic analysis

Ablative surgery has been a standard procedure for many years, but during the past few years there has been a significant improvement in our understanding of invasion and metastasis in oral cancer. Each procedure has to be planned individually. Before surgery, every attempt must have been made to arrive at a proper diagnosis, including the exact nature and aggressiveness of the tumor and an analysis of the patient's genetic background. These procedures and the prognosis will be discussed.

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.