Detecting early oral cancer: narrowband imaging system observation of the oral mucosa microvasculature

Abstract

The aim of this study was to analyze and describe the intrapapillary capillary loops (IPCL), which are a feature of early oral neoplastic lesions, using a narrowband imaging (NBI) system. Forty-one patients (26 men, 15 women; mean age, 52.34 years; range, 23–83 years) presenting with non-neoplastic or neoplastic lesions, and normal cases, were examined using the prototype Evis Lucera Spectrum (Olympus Co.). The images were analyzed and an IPCL classification was devised. All normal cases ( n = 10) had regularly distributed capillary loops of the same shape (type I). Non-neoplastic lesions ( n = 8) had mild changes of the capillary loops (types II and III) and neoplastic lesions ( n = 23) were irregularly distributed and had several loop shapes (types III and IV). The microvascular organization of non-neoplastic lesions was notably different from that of neoplastic lesions. A brownish area was found in five cases of early carcinoma. The narrowband imaging system is a potential approach for clinically analyzing microvascular organization and IPCL. It could be useful for diagnosing oral squamous cell carcinoma at an earlier stage and for determining the margin of resection.

Oral cancer is generally detected by visual inspection of the abnormalities on the surface of the mucosa. Detection of cancer at an earlier stage is important because most advanced lesions require extensive surgical resection . Precise observation of the colour variation and the fine structural pattern of the mucosa is required to diagnose possible malignancy .

Narrowband imaging (NBI) is an endoscopic technique based on the use of special optical filters that narrow the light bandwidth to enhance the visualization of the mucosa surface and microvasculature . NBI associated with a magnification zoom facility is useful for the accurate diagnosis of early cancers due to the contrast observation of vascular architecture, in particular the intrapapillary capillary loops (IPCL) .

In neoplastic lesions, the IPCL are modified by dilation, meandering and calibre irregularities that can be differentiated from normal mucosa . Morphological changes to the IPCL are useful for diagnosing early cancers, and determining the depth of invasion and the margin of resection .

The effectiveness of NBI in detecting early dysplastic lesions in the pharynx and oesophagus encouraged the authors to analyze the oral cavity. The purpose of the present study was to analyze and describe the features of IPCL from early oral neoplastic lesions using NBI and to discuss the clinical relevance of using NBI for detecting oral cancer.

Material and method

Examinations were carried out with a prototype Evis Lucera Spectrum Video Imaging System (CV-260SL processor and CLV-260SL light source; Olympus Medical Systems Corp., Tokyo, Japan; Fig. 1 ). The system contains standard and NBI filters, which can be changed during the examination by switching a button on the keyboard. The rotating interference red-green-blue (RGB) narrow-band filter is interposed after the xenon light source where the light passes through and narrows the bandwidth, changing the spectral characteristics of the incident light . The optical filters have a centre wavelength of 500 nm, 445 nm and 415 nm (bandwidth of 30 nm for each filter) which corresponds to penetration depths of 240 μm, 200 μm, and 170 μm, respectively .

Fig. 1
NBI comprising monitor, NBI light source, image processor, conventional light source and keyboard.

The light penetration depth depends on the wavelength, probably due to the absorption and scattering process that occurs in the structures of the tissue . Short wavelengths (blue light) scatter easily and are absorbed selectively by haemoglobin , providing good contrast for the mucosa microvasculature, mainly the capillary loops. Longer wavelengths (red light) scatter minimally and penetrate more deeply. Each reflected light spectral feature is captured by a charge-coupled device chip at the tip of the endoscope and a unique high-resolution, contrast image is reconstructed at the monitor from the structures .

Forty-one patients (26 men, 15 women; mean age, 52.34 years; range, 23–83 years) who presented with non-neoplastic or neoplastic lesions, and normal cases were examined in this study ( Table 1 ). All patients gave written informed consent before the procedures.

Table 1
Pathology, TMN classification, diabetes mellitus, smoking status, and IPCL type for each case.
Case Age Gender Diagnosis Site Classification IPCL
1 75 M SCC Gingiva T2N0M0 (M) IV
2 64 M SCC Tongue T3N2cM0 (W) III
3 47 M SCC Tongue T2N2aM0 (M) IV
4 83 F SCC Gingiva T2N0M0 (W) III
5 44 M SCC Tongue T1N0M0 (W) III
6 38 F SCC Tongue T1N0M0 (W) III
7 76 M SCC Oral floor T1N0M0 (W) III
8 62 M SCC Tongue T1N0M0 (W) IV
9 79 F SCC Gingiva T2N0M0 (W) III
10 68 M SCC Tongue T2N0M0 (W) III
11 38 F SCC Tongue T1N0M0 (W) IV
12 62 M SCC Tongue T1N0M0 (W) IV
13 52 M SCC Tongue T1N0M0 (W) III
14 71 M SCC Gingiva T4N1M0 (W) IV
15 52 M SCC Tongue T1N0M0 (W) III
16 64 M SCC Tongue T2N2bM0 (W) IV
17 26 F SCC Tongue T1N0M0 (W) IV
18 76 F SCC Buccal mucosa T1N0M0 (W) III
19 53 M SCC Tongue T2N2bM0 (P) IV
20 63 F SCC Tongue T1N0M0 (W) IV
21 70 F SCC Buccal mucosa T2N2bM0 (M) IV
22 66 M SCC Tongue T2N2bM0 (W) III
23 48 M SCC Tongue T1N0M0 (W) III
24 80 F Leukoplakia Tongue III
25 68 F Leukoplakia Gingiva III
26 69 F Leukoplakia Tongue III
27 80 F Leukoplakia Gingiva III
28 43 M Leukoplakia Gingiva II
29 24 M Aphytha Lower lip II
30 30 M Aphytha Tongue II
31 29 M Normal Lower lip I
32 56 F Normal Lower lip I
33 23 M Normal Lower lip I
34 31 M Normal Lower lip I
35 25 M Normal Lower lip I
36 27 M Normal Lower lip I
37 27 F Normal Lower lip I
38 33 M Normal Lower lip I
39 24 M Normal Lower lip I
40 33 M Normal Lower lip I
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Feb 8, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Detecting early oral cancer: narrowband imaging system observation of the oral mucosa microvasculature
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