Fluorescence molecular imaging for identification of high-grade dysplasia in patients with head and neck cancer

Abstract

Objective: High-grade dysplasia is associated with a risk of malignant transformation, and it is necessary to distinguish from normal epithelium or low-grade dysplasia, especially in the intraoperative setting. We hypothesize that an anti-epidermal growth factor receptor (EGFR) contrast agent can be used to differentiate high-grade dysplasia from low-grade dysplasia and normal epithelium.

Materials and methods: Patients with biopsy proven head and neck squamous cell carcinoma (HNSCC) were enrolled in a clinical trial using systemically injected fluorescently labeled anti-EGFR antibody (panitumumab-IRDye800CW) (NCT02415881). Paraffin embedded tumor specimens from 11 patients were evaluated by fluorescence histopathology. Hematoxylin and eosin (H&E) slides were reviewed by a board-certified pathologist, and regions of invasive squamous cell carcinoma, high-grade dysplasia and low-grade dysplasia were delineated. EGFR expression was assessed for each patient by way of immunohistochemistry.

Results: 11 patients were included in the study with a total of 219 areas on tissue sections analyzed; 68 normal epithelium, 53 low-grade dysplasia, 48 high-grade dysplasia, and 50 malignant regions. The signal-to-background ratio (SBR) increased proportionally with increasing grade of dysplasia; normal epithelium (1.5 ± 0.1), low-grade dysplasia (1.8 ± 0.1), high-grade dysplasia: (2.3 ± 0.2). High-grade dysplasia had a significantly higher SBR when compared to normal or low-grade dysplasia (p < 0.05). Fluorescence histopathology positively correlated with EGFR expression by immunohistochemistry, which also increased proportionally with increasing degree of dysplasia.

Conclusion: Molecular imaging with an anti-EGFR agent can successfully discriminate high-grade dysplastic lesions from low-grade dysplasia and normal epithelium.

Keywords: Antibody; Dysplasia; Fluorescence imaging; Head and neck cancer; Molecular imaging; Near-infrared; Oral cavity.

Conflict of interest statement

Disclosures

All other authors declare no conflict of interest.

Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.

Figures

Figure 1.. Fluorescence histopathology of 10 micron slides from patient specimen.

(a) Average SBR, with standard error of the mean, for each grade. (b-i) Representative images of the H&E (top) and fluorescence (bottom) for each of the grades. Representative images of (b,f) normal epithelium, (c,g) low-grade dysplasia, (d,h) high-grade dysplasia, and (e,i) invasive squamous cell carcinoma. LG = low-grade dysplasia, HG = high-grade dysplasia, SCC = squamous cell carcinoma. Statistical analysis by Mann-Whitney U test.

Figure 2.. EGFR immunohistochemistry staining of 10 micron slides from patients specimen.

(a) EGFR expression, with standard error, of the 10 micron slides by grade. (b-i) Representative images of the H&E (top) and IHC (bottom) for each of the grades. Representative images for (b,f) normal epithelium, (c,g) low-grade dysplasia, (d,h) high-grade dysplasia, and (e,i) invasive squamous cell carcinoma. LG=low-grade dysplasia, HG=high-grade dysplasia, SCC= squamous cell carcinoma. Statistical analysis by Mann-Whitney U test.

Figure 3.. Fluorescence imaging of macroscopic sections from patient specimen.

(a) One representative H&E with regions of interest outlined (top) and the corresponding fluorescence image of the macroscopic tissue section with the corresponding regions delineated (bottom). (b) Average SBR (with standard error bars) of the 5 mm, macroscopic tissue sections by grade. LG = low-grade dysplasia, HG = high-grade dysplasia, SCC = squamous cell carcinoma. Statistical analysis by Mann-Whitney U test.

Figure 4.. Fluorescence imaging of whole patient specimen.

(a) A representative fluorescence image of a specimen. The dotted line corresponds to (b) the H&E with regions of interest delineated. (d) The signal value curve over the representative line displayed in (a-b). (c) Average SBR, with standard error, of the whole specimen for Normal/LG and HG/SCC tissue. LG = low-grade dysplasia, HG = high-grade dysplasia, SCC = squamous cell carcinoma, N/L = normal-to-low grade. Statistical analysis by Mann-Whitney U test.