The use of Velscope to assess cellular changes occuring in oral premalignancy

Abstract

Objectives

To improve visualization of suspicious lesions of the oral mucosa and to assess the accuracy of Velscope in assessing cellular changes occurring in oral premalignancy for early diagnosis.

Materials and methods

In this prospective, randomized in-vivo clinical study a total of 250 patients who gave history of chewing tobacco were screened. The selection of the site of biopsy was taken based on the area of loss of fluorescence identified by the Velscope within the lesion. Routine blood investigations were done. A biopsy was performed to confirm the findings of clinical examination. The data was collected and analysed.

Results

Among 200 patients only 110 underwent incisional biopsy. Of these only 89 patients showed neoplastic changes. Of the control biopsies, none of them showed any dysplastic changes. Out of 106 who exhibited speckling under autofluorescence, only 89 showed dysplastic changes whereas only 17 showed no dysplastic changes. Out of these 17 specimens, the histopathological diagnosis of 5 was coated tongue, 3 were pigmented lesions, 3 were geographic tongue and 2 were mucositis. Of the remaining 4, the histopathological diagnosis of 1 was oral submucous fibrosis, 1 was lichen planus and 2 were frictional keratosis.

Conclusion

False positive findings are possible in presence of highly inflamed tissues, and it is possible that use of Velscope alone may result in failure to detect regions of dysplasia, but it has its use definitely to improve clinical decision making about the nature of oral lesions and aids in decisions to biopsy regions of concern. Use of the scope has allowed practitioners to identify the best region for biopsy. It is much better to occasionally sample tissue that turns out to be benign than to fail to diagnose dysplastic or malignant lesions. However, poor specificity is a major limitation for using it as a screening tool.

Introduction

The incidence of oral cancer worldwide, is approximately 3% of all malignancies and this is creating a remarkable health problem.¹ Oral cancer is showing a rise in incidence by every passing year and is being recognized in the late stage. Late detection and diagnosis can be attributed to the inadequacy in training of health professionals. Early diagnosis of curable precursors of malignancy is still the best way to make sure that there is improvement in both survival rate and quality of life, along with the eminent advances in cancer treatment.^2,3 Generally, the primarily important factor that decides the mortality rate in these patients is the clinical stage during diagnosis of the same. The diagnosis of oral cancer is influenced to a great extent by not only the patient reluctance to consult or due to inability to access a health care professional but also professional delay in diagnosis. The patients’ survival rate can be improved if the lesion before its malignant progression from leukoplakia is diagnosed at an early stage. The early detection and screening plays a major role in decreasing the morbidity and mortality of the disease.^4,5

Early diagnosis of oral malignancy makes the treatment early and unaggressive and also boosts the survival rate to 80%.⁶ Oral health care professionals are the ones who detect malignancy and premalignant conditions in the early stages and they make a considerable contribution in decreasing the incidence and identifying the high risk patients and imparting good healthy habits education to them. By means of the combination of visual examination and palpation, detection of epithelial changes in oral mucosa is the main approach presently and is well known to be confined to an impressionistic interpretation. This is then followed by tissue biopsy with the histopathological assessment that is considered as the gold standard for the diagnosis,⁷ but this requires a well-trained health care professional and is also believed to be invasive, painful, expensive and time consuming. Any approach that makes easy the visualization of a dubious lesion could help a clinician to detect oral cancer in its early stages. Hence, the reason why there has been an evolution of several light induced fluorescence visualization appliances like the VELscope (Visually enhanced lesion scope), is due to the increased demand for non-invasive tests that will intensify the regular white light oral examination for the diagnosis of potentially malignant lesions. This system presents with a sensitivity of 98% and specificity of 96%–100%.8, 9, 10 Under a hypothesis, there could exist a molecular difference in the squamous cell carcinoma occurring in western and eastern populations. Accordingly there could be a difference in the behavior of these cells in other aspects also. Thus this study was designed to test the efficacy of VELscope in assessing the cellular changes occurring in oral premalignancy in Indian population. This study is laid on the usefulness of the Velscope as a diagnostic aid to assess its efficacy in distinguishing the cellular changes in oral premalignancy.

The working principle of the Velscope system relies on the loss of fluorescence in visible and non -visible high risk oral lesions can be identified by applying direct fluorescence. It comprises of a light source that emits a wavelength of 400–460 nm and a manual unit for visualization. Green auto-fluorescence is emitted by the normal mucosa whereas the fluorescent light is absorbed by abnormal areas making them appear dark, under this light[Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6]. Normally occurring fluorophores in the tissue are a basis for the mechanism of tissue fluorescence that determine their reflective and absorptive pattern. Different profile areas undergoing malignant changes in which loss of fluorescence visualization is seen may maximize on the exposure to blue light spectra (400–460 nm). Therefore, pre-malignant changes are diagnosed even before its clinical appearance. Thus the Velscope system can be used as a complement to visual examination for:

• Distinguishing between normal and abnormal tissues (both benign and malignant) is enhanced.

• Benign and neoplastic changes can be differentiated and/or delineated.

• Dysplastic or malignant lesions margins that are invisible to the naked eye under white light can be visualized.⁹