Near-infrared fluorescence imaging improves the nodal yield in neck dissection in oral cavity cancer - A randomized study

Near-infrared imaging of head and neck squamous cell carcinoma using indocyanine green that targets the αvβ6 peptide

Significance

Head and neck squamous cell carcinoma (HNSCC) has a particularly poor prognosis. Improving the surgical resection boundary, reducing local recurrence, and ultimately ameliorating the overall survival rate are the treatment goals.

Aim

To obtain a complete surgical resection (R0 resection), we investigated the use of a fluorescent imaging probe that targets the integrin subtype α v β 6 , which is upregulated in many kinds of epithelial cancer, using animal models.

Approach

α v β 6 expression was detected using polymerase chain reaction (PCR) and immunoprotein blotting of human tissues for malignancy. Protein expression localization was observed. α v β 6 and epidermal growth factor receptor (EGFR) were quantified by PCR and immunoprotein blotting, and the biosafety of targeting the α v β 6 probe material was examined using Cell Counting Kit-8 assays. Indocyanine green (ICG) was used as a control to determine the localization of the probe at the cellular level. In vivo animal experiments were conducted through tail vein injections to evaluate the probe's imaging effect and to confirm its targeting in tissue sections.

Results

α v β 6 expression was higher than EGFR expression in HNSCC, and the probe showed good targeting in in vivo and in vitro experiments with a good safety profile.

Conclusions

The ICG-α v β 6 peptide probe is an exceptional and sensitive imaging tool for HNSCC that can distinguish among tumor, normal, and inflammatory tissues.

Interventions for the treatment of oral cavity and oropharyngeal cancers: surgical treatment

BACKGROUND

Surgery is a common treatment option in oral cavity cancer (and less frequently in oropharyngeal cancer) to remove the primary tumour and sometimes neck lymph nodes. People with early-stage disease may undergo surgery alone or surgery plus radiotherapy, chemotherapy, immunotherapy/biotherapy, or a combination of these. Timing and extent of surgery varies. This is the third update of a review originally published in 2007.

OBJECTIVES

To evaluate the relative benefits and harms of different surgical treatment modalities for oral cavity and oropharyngeal cancers.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 9 February 2022.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared two or more surgical treatment modalities, or surgery versus other treatment modalities, for primary tumours of the oral cavity or oropharynx.

DATA COLLECTION AND ANALYSIS

Our primary outcomes were overall survival, disease-free survival, locoregional recurrence, and recurrence; and our secondary outcomes were adverse effects of treatment, quality of life, direct and indirect costs to patients and health services, and participant satisfaction. We used standard Cochrane methods. We reported survival data as hazard ratios (HRs). For overall survival, we reported the HR of mortality, and for disease-free survival, we reported the combined HR of new disease, progression, and mortality; therefore, HRs below 1 indicated improvement in these outcomes. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We identified four new trials, bringing the total number of included trials to 15 (2820 participants randomised, 2583 participants analysed). For objective outcomes, we assessed four trials at high risk of bias, three at low risk, and eight at unclear risk. The trials evaluated nine comparisons; none compared different surgical approaches for excision of the primary tumour. Five trials evaluated elective neck dissection (ND) versus therapeutic (delayed) ND in people with oral cavity cancer and clinically negative neck nodes. Elective ND compared with therapeutic ND probably improves overall survival (HR 0.64, 95% confidence interval (CI) 0.50 to 0.83; I2 = 0%; 4 trials, 883 participants; moderate certainty) and disease-free survival (HR 0.56, 95% CI 0.45 to 0.70; I2 = 12%; 5 trials, 954 participants; moderate certainty), and probably reduces locoregional recurrence (HR 0.58, 95% CI 0.43 to 0.78; I2 = 0%; 4 trials, 458 participants; moderate certainty) and recurrence (RR 0.58, 95% CI 0.48 to 0.70; I2 = 0%; 3 trials, 633 participants; moderate certainty). Elective ND is probably associated with more adverse events (risk ratio (RR) 1.31, 95% CI 1.11 to 1.54; I2 = 0%; 2 trials, 746 participants; moderate certainty). Two trials evaluated elective radical ND versus elective selective ND in people with oral cavity cancer, but we were unable to pool the data as the trials used different surgical procedures. Neither study found evidence of a difference in overall survival (pooled measure not estimable; very low certainty). We are unsure if there is a difference in effect on disease-free survival (HR 0.57, 95% CI 0.29 to 1.11; 1 trial, 104 participants; very low certainty) or recurrence (RR 1.21, 95% CI 0.63 to 2.33; 1 trial, 143 participants; very low certainty). There may be no difference between the interventions in terms of adverse events (1 trial, 148 participants; low certainty). Two trials evaluated superselective ND versus selective ND, but we were unable to use the data. One trial evaluated supraomohyoid ND versus modified radical ND in 332 participants. We were unable to use any of the primary outcome data. The evidence on adverse events was very uncertain, with more complications, pain, and poorer shoulder function in the modified radical ND group. One trial evaluated sentinel node biopsy versus elective ND in 279 participants. There may be little or no difference between the interventions in overall survival (HR 1.00, 95% CI 0.90 to 1.11; low certainty), disease-free survival (HR 0.98, 95% CI 0.90 to 1.07; low certainty), or locoregional recurrence (HR 1.04, 95% CI 0.91 to 1.19; low certainty). The trial provided no usable data for recurrence, and reported no adverse events (very low certainty). One trial evaluated positron emission tomography-computed tomography (PET-CT) following chemoradiotherapy (with ND only if no or incomplete response) versus planned ND (before or after chemoradiotherapy) in 564 participants. There is probably no difference between the interventions in overall survival (HR 0.92, 95% CI 0.65 to 1.31; moderate certainty) or locoregional recurrence (HR 1.00, 95% CI 0.94 to 1.06; moderate certainty). One trial evaluated surgery plus radiotherapy versus radiotherapy alone and provided very low-certainty evidence of better overall survival in the surgery plus radiotherapy group (HR 0.24, 95% CI 0.10 to 0.59; 35 participants). The data were unreliable because the trial stopped early and had multiple protocol violations. In terms of adverse events, subcutaneous fibrosis was more frequent in the surgery plus radiotherapy group, but there were no differences in other adverse events (very low certainty). One trial evaluated surgery versus radiotherapy alone for oropharyngeal cancer in 68 participants. There may be little or no difference between the interventions for overall survival (HR 0.83, 95% CI 0.09 to 7.46; low certainty) or disease-free survival (HR 1.07, 95% CI 0.27 to 4.22; low certainty). For adverse events, there were too many outcomes to draw reliable conclusions. One trial evaluated surgery plus adjuvant radiotherapy versus chemotherapy. We were unable to use the data for any of the outcomes reported (very low certainty).

AUTHORS' CONCLUSIONS

We found moderate-certainty evidence based on five trials that elective neck dissection of clinically negative neck nodes at the time of removal of the primary oral cavity tumour is superior to therapeutic neck dissection, with increased survival and disease-free survival, and reduced locoregional recurrence. There was moderate-certainty evidence from one trial of no difference between positron emission tomography (PET-CT) following chemoradiotherapy versus planned neck dissection in terms of overall survival or locoregional recurrence. The evidence for each of the other seven comparisons came from only one or two studies and was assessed as low or very low-certainty.

Prognostic Value of Lymph Node Yield, Lymph Node Density, and pN in Oral Cancer

OBJECTIVES

To investigate thresholds for lymph node yield (LNY), lymph node density (LND), and pN in patients with oral squamous cell carcinoma in relation to previous findings in the literature.

STUDY DESIGN

Retrospective register-based study.

SETTING

Copenhagen Oral Cavity Squamous Cell Carcinoma database.

METHODS

Appropriate thresholds for LNY, LND, and pN were determined by areas under the curve and subsequently subjected to multivariate analysis. Five-year overall survival and 3-year recurrence-free survival were determined by Kaplan-Meier survival curves.

RESULTS

In total, 413 patients diagnosed with oral squamous cell carcinoma were included. In the pN0 cohort, no superior/prognostic LNY cutoff values were detected. In the pN+ cohort, areas under the curve determined thresholds of LNY, LND, and pN to be 21 nodes, 5%, and 3 metastases, respectively. The 5-year overall survival was 52% for patients with LNY ≥21 vs 38% for patients with LNY <21 (hazard ratio [HR], 1.49; 95% CI, 1.05-2.11; P < .05), 60% for patients with LND ≤5% vs 38% for patients with LND >6% (HR, 1.63; 95% CI, 1.03-2.57; P < .05), and 43% for patients with pN <3 vs 26% for patients with pN ≥3 (HR, 1.40; 95% CI, 1.04-2.15; P < .05).

CONCLUSIONS

Increased nodal yield, decreased LND, and decreasing number of pN were associated with significantly improved survival outcomes. LNY might serve as a prognosticator of survival as well as a surgical quality indicator. LND may have implications as a tool in cancer staging and treatment planning.

A Truncated 14-Amino-Acid Myelin Protein-Zero-Targeting Peptide for Fluorescence-Guided Nerve-Preserving Surgery

BACKGROUND

The occurrence of accidental nerve damage during surgery and the increasing application of image guidance during head-and-neck surgery have highlighted the need for molecular targeted nerve-sparing interventions. The implementation of such interventions relies on the availability of nerve-specific tracers. In this paper, we describe the development of a truncated peptide that has an optimized affinity for protein zero (P0), the most abundant protein in myelin.

METHODS AND MATERIALS

Further C- and N-terminal truncation was performed on the lead peptide Cy5-P0_101-125. The resulting nine Cy5-labelled peptides were characterized based on their photophysical properties, P0 affinity, and in vitro staining. These characterizations were combined with evaluation of the crystal structure of P0, which resulted in the selection of the optimized tracer Cy5-P0_112-125. A near-infrared Cy7-functionalized derivative (Cy7-P0_112-125) was used to perform an initial evaluation of fluorescence-guided surgery in a porcine model.

RESULTS

Methodological truncation of the 26-amino-acid lead compound Cy5-P0_101-125 resulted in a size reduction of 53.8% for the optimized peptide Cy5-P0_112-125. The peptide design and the 1.5-fold affinity gain obtained after truncation could be linked to interactions observed in the crystal structure of the extracellular portion of P0. The near-infrared analogue Cy7-P0_112-125 supported nerve illumination during fluorescence-guided surgery in the head-and-neck region in a porcine model.

CONCLUSIONS

Methodological truncation yielded a second-generation P0-specific peptide. Initial surgical evaluation suggests that the peptide can support molecular targeted nerve imaging.

Novel double injection technique for sentinel lymph node biopsy in oral cancer

The development of new lymphatic tracers and the advancement of hybrid tracers, such as indocyanine green (ICG)-Nanocoll (GE Healthcare), represent an exciting step in the future of sentinel lymph node biopsy (SLNB). These tracers aim to improve our ability to detect sentinel lymph nodes by enhancing their localisation. The aim of this study was to assess the performance of a novel dual tracer, double injection technique of ICG-'cold'-Nanocoll and radiolabelled Nanocoll, in SLNB for early-stage oral cancer. A double injection technique was performed first using ^99mTc-Nancoll prior to sentinel node imaging followed by ICG-'cold'-Nanocoll injection in theatre. Analysis involved examination of the number, labelling, and location of the nodes harvested, sentinel node status, survival analysis, false negative rate, and complications associated with use of the technique. ICG 'cold' Nanocoll results showed concordance of fluorescence and radioactivity detection in 74 nodes in 24 patients. Most importantly, all nodes found positive for metastasis (6 nodes) were discovered to be both 'hot' and fluorescent; 74 nodes removed were both 'hot' and fluorescent, eight fluorescent only and six 'hot' only. Our results indicate that two sets of tracer injections given at two different time points will flow to the same sentinel nodes. This double labelling increased our confidence that the retrieved node was a sentinel node.

Translation of c-Met Targeted Image-Guided Surgery Solutions in Oral Cavity Cancer-Initial Proof of Concept Data

Simple Summary

Translation of tumor-specific fluorescent tracers is crucial in the realization intraoperative of tumor identification during fluorescence-guided surgery. Ex vivo assessment of surgical specimens after topical tracer application has the potential to reveal the suitability of a potential surgical target prior to in vivo use in patients. In this study, the c-Met receptor was identified as a possible candidate for fluorescence-guided surgery in oral cavity cancer. Freshly excised tumor specimens obtained from ten patients with squamous cell carcinoma of the tongue were incubated with EMI-137 and imaged with a clinical-grade Cy5 prototype fluorescence camera. In total, 9/10 tumors were fluorescently illuminated, while non-visualization could be linked to non-superficial tumor localization. Immunohistochemistry revealed c-Met expression in all ten specimens. Tumor assessment was improved via video representation of the tumor-to-background ratio.

Abstract

Intraoperative tumor identification (extension/margins/metastases) via receptor-specific targeting is one of the ultimate promises of fluorescence-guided surgery. The translation of fluorescent tracers that enable tumor visualization forms a critical component in the realization of this approach. Ex vivo assessment of surgical specimens after topical tracer application could help provide an intermediate step between preclinical evaluation and first-in-human trials. Here, the suitability of the c-Met receptor as a potential surgical target in oral cavity cancer was explored via topical ex vivo application of the fluorescent tracer EMI-137. Freshly excised tumor specimens obtained from ten patients with squamous cell carcinoma of the tongue were incubated with EMI-137 and imaged with a clinical-grade Cy5 prototype fluorescence camera. In-house developed image processing software allowed video-rate assessment of the tumor-to-background ratio (TBR). Fluorescence imaging results were related to standard pathological evaluation and c-MET immunohistochemistry. After incubation with EMI-137, 9/10 tumors were fluorescently illuminated. Immunohistochemistry revealed c-Met expression in all ten specimens. Non-visualization could be linked to a more deeply situated lesion. Tumor assessment was improved via video representation of the TBR (median TBR: 2.5 (range 1.8–3.1)). Ex vivo evaluation of tumor specimens suggests that c-Met is a possible candidate for fluorescence-guided surgery in oral cavity cancer.