Fluorescence imaging to localize head and neck squamous cell carcinoma for enhanced pathological assessment

Abstract

Accurately identifying close or positive margins in real‐time permits re‐excision during surgical procedures. Intraoperative assessment of margins via gross examination and frozen section is a widely used tool to assist the surgeon in achieving complete resection. While this methodology permits diagnosis of freshly resected tissue, the process is fraught with misinterpretation and sampling errors. During fluorescence‐guided surgery, an exogenous fluorescent agent specific for the target disease is imaged in order to navigate the surgical excision. As this technique quickly advances into the clinic, we hypothesize that the disease‐specific fluorescence inherently contained within the resected tissues can be used to guide histopathological assessment. To evaluate the feasibility of fluorescence‐guided pathology, we evaluated head and neck squamous cell carcinoma tumour specimens and margins resected from animals and patients after systemic injection of cetuximab‐IRDye800CW. In a preclinical model of luciferase‐positive tumour resection using bioluminescence as the gold standard, fluorescence assessment determined by closed‐field fluorescence imaging of fresh resected margins accurately predicted the presence of disease in 33/39 positive margins yielding an overall sensitivity of 85%, specificity of 95%, positive predictive value (PPV) of 94%, and a negative predictive value (NPV) of 87%, which was superior to both surgical assessment (54%, 61%, 57%, and 58%) and pathological assessment (49%, 95%, 91%, and 66%), respectively. When the power of the technique was evaluated using human‐derived tumour tissues, as little as 0.5mg (1mm3) of tumour tissue was identified (tumour‐to‐background‐ratio:5.2). When the sensitivity/specificity of fluorescence‐guided pathology was determined using traditional histological assessment as the gold standard in human tissues obtained during fluorescence‐guided surgery, the technique was highly accurate with a sensitivity of 91%, specificity of 85%, PPV of 81%, and NPV of 93% for 90 human‐derived samples. This approach can be used as a companion to the pathologist, eliminating confounding factors while impacting surgical intervention and patient management.

Specimen mapping in head and neck cancer using fluorescence imaging

“…We showed that 5 mg of tumor could be identified in the clinical setting as shown in Fig. ; this exceeds current detection thresholds reported in the literature …”

“…From the studies, intravenous administration of fluorescently labeled anti‐EGFR antibody can image cutaneous and mucosal squamous cell carcinoma in vivo and ex vivo and throughout histology processing since the dye is not significantly degraded by formalin fixation and paraffin embedding . Using a range of devices as listed in T, the tissue can be imaged at each step–intraoperatively or in the clinic (Fig.…”

Characterizing the detection threshold for optical imaging in surgical oncology

“…Results from a recent clinical trial of cetuximab‐IRDye800CW demonstrated sufficient specificity to fluorescently localize disease in HNSCC patients . Using this antibody‐based method, fluorescence contrast delivers a more sensitive and specific approach when compared to a surgical and pathological evaluation . When compared to standard histopathological evaluation, florescence imaging has the potential to permit evaluation of the entire wound bed, which could greatly reduce sampling error.…”

“…2LMP cells incubated Using this antibody-based method, fluorescence contrast delivers a more sensitive and specific approach when compared to a surgical and pathological evaluation. 20 When compared to standard histopathological evaluation, florescence imaging has the potential to permit evaluation of the entire wound bed, which could greatly reduce sampling error. Accurate localization is further supported at the cellular level as histologic assessment of florescence sequestration demonstrates a statistically significant (P < 0.001) delineation between cancerous/non-cancerous tissues at 1 mm from the tumor border.…”

Fluorescence-guided laparoscopic hepatectomy

“…Clinical applications of tumor-specific fluorescent dyes under trials currently include fluorescent folate to label ovarian cancer and fluorescent cetuximab to label head and neck cancers, but data on survival advantage and rate of tumor recurrence are not yet available (23,24). The number of fluorescence labeling platforms will greatly increase in the future along with further data on their impact of oncologic outcomes.…”