Frontal and anterior temporal hypometabolism post chemoradiation in head and neck cancer: A real-world PET study

BACKGROUND AND PURPOSE

Adverse neurological effects after cancer therapy are common, but biomarkers to diagnose, monitor, or risk stratify patients are still not validated or used clinically. An accessible imaging method, such as fluorodeoxyglucose positron emission tomography (FDG PET) of the brain, could meet this gap and serve as a biomarker for functional brain changes. We utilized FDG PET to evaluate which brain regions are most susceptible to altered glucose metabolism after chemoradiation in patients with head and neck cancer (HNCa).

METHODS

Real-world FDG PET images were acquired as standard of care before and after chemoradiation for HNCa in 68 patients. Linear mixed-effects voxelwise models assessed changes after chemoradiation in cerebral glucose metabolism quantified with standardized uptake value ratio (SUVR), covarying for follow-up time and patient demographics.

RESULTS

Voxelwise analysis revealed two large clusters of decreased glucose metabolism in the medial frontal and polar temporal cortices following chemoradiation, with decreases of approximately 5% SUVR after therapy.

CONCLUSIONS

These findings provide evidence that standard chemoradiation for HNCa can lead to decreased neuronal glucose metabolism, contributing to literature emphasizing the vulnerability of the frontal and anterior temporal lobes, especially in HNCa, where these areas may be particularly vulnerable to indirect radiation-induced injury. FDG PET shows promise as a sensitive biomarker for assessing these changes.

Identification of Optimal Tissue-Marking Dye Color for Pathological Evaluation in Fluorescence Imaging Using IRDye800CW

PURPOSE

Fluorescence-guided surgery using a tumor-specific antibody-dye conjugate is useful in various cancer types. Fluorescence imaging is a valuable tool both intraoperatively and postoperatively for ex vivo imaging. The color of inks used for tumor specimens during ex vivo specimen processing in pathology is an important consideration for fluorescence imaging since the absorption/emission of the dyes may interfere with the fluorescent dye. This study assesses suitable ink colors for use specifically with IRDye800CW fluorescence imaging.

PROCEDURES

Eight tissue-marking inks or dyes (TMDs) commonly used for pathological evaluation were assessed. Agarose tissue-mimicking phantoms containing Panitumumab-IRDye800CW were used as an initial model. Mean fluorescence intensity was measured at 800 nm using both Pearl Trilogy as a closed-field fluorescence imaging system and pde-neo II as an open-field fluorescence imaging system before and after TMD application. An in vivo mouse xenograft model using the human head and neck squamous cell carcinoma FaDu cell line was then used in conjunction with TMDs.

RESULTS

The retained IRDye800CW fluorescence on Pearl Trilogy was as follows: yellow at 91.0 ± 4.5%, red at 90.6 ± 2.7%, orange at 88.2 ± 2.2%, violet at 56.6 ± 1.1%, lime at 40.9 ± 1.8%, green at 19.3 ± 2.8%, black at 13.3 ± 0.6%, and blue at 8.1 ± 0.2%. The retained IRDye800CW fluorescence on pde-neo II was as follows: yellow at 86.5 ± 6.4%, red at 77.0 ± 6.2%, orange at 76.9 ± 2.8%, lime at 72.5 ± 9.5%, violet at 59.7 ± 0.4%, green at 30.1 ± 6.9%, black at 17.0 ± 2.7%, and blue at 6.7 ± 1.7%. The retained IRDye800CW fluorescence in yellow and blue TMDs was 42.1 ± 14.9% and 0.2 ± 0.2%, respectively in the mouse experiment (p = 0.039).

CONCLUSION

Yellow, red, and orange TMDs should be used, and blue and black TMDs should be avoided for evaluating tumor specimens through fluorescence imaging using IRDye800CW.

Impact of comorbidities on immediate post-operative complications in oral cavity free flap patients

PURPOSE

To examine the relationship between comorbidities and the development of immediate post-operative complications in patients undergoing oral cavity composite resection (OCCR) with free flap (FF) reconstruction.

MATERIALS AND METHODS

Retrospective analysis was completed on all consecutive OCCRs with FF reconstruction performed at a single quaternary care facility between 1999 and 2020. Comorbidities, immediate post-operative complications, patient demographics, and tumor characteristics were collected. Odds ratios (OR) with 95 % confidence intervals were calculated for associations between comorbidities and immediate post-operative complications.

RESULTS

320 patients who underwent OCCR with FF reconstruction were included. One hundred twenty-one (37.8 %) patients developed a post-operative complication during their initial hospital admission. The most common complications were non-pneumonia cardiopulmonary events (14.1 %), pneumonia (9.4 %), and wound infection (8.4 %). Other complications included flap compromise, bleeding, and fistula. On multivariate analysis, patients without comorbid conditions were less likely to develop a post-operative complication (OR 0.64; 0.41-0.98). Atrial fibrillation (OR 2.94; 1.17-7.39) and cerebrovascular disease (OR 2.28; 1.08-4.84) were associated with increased odds of developing any complications. Furthermore, cerebrovascular disease (OR: 2.33; 1.04-5.39) and peripheral vascular disease (OR: 2.7; 1.2-6.08) were independently associated with pneumonia.

CONCLUSION

In this retrospective review of patients undergoing OCCR with FF reconstruction for oral cavity SCC, lack of identifiable comorbidities appeared to be protective for post-operative complications while atrial fibrillation and cerebrovascular disease were associated with increased odds of any complication. Pre-existing vascular disease was also associated with an increased risk of pneumonia.

Virtual 3D Specimen Mapping in Head & Neck Oncologic Surgery

OBJECTIVES

Virtual 3D specimen mapping of oncologic surgical specimens provides a visual record of the specimen and margin sampling sites which can be utilized in a variety of cancer care settings. Our objective was to perform a retrospective review of head and neck surgical oncology cases where the specimen was mapped post-operatively and to evaluate the utility of these 3D specimen maps amongst the multidisciplinary cancer care team.

METHODS

A retrospective review of our 3D specimen model biorepository was performed. Surgical specimens were 3D scanned and then graphically annotated (or "mapped") during routine pathologic processing. The resulting 3D specimen maps were distributed to the multidisciplinary oncologic care team. Final margin status and any use of the 3D specimen maps were recorded.

RESULTS

A total of 28 cases were included. Virtual 3D specimen maps were utilized by the cancer care team in 8 cases (29%), including 2 positive margin cases, 2 close margin cases, and 4 indeterminate margin cases. 3D specimen maps were used to visualize positive margin sites for pathologist-surgeon communication as a visual reference during tumor board discussions and to inform radiation treatment planning.

CONCLUSION

Post-operative virtual 3D specimen mapping of oncologic specimens creates a permanent visual record of the specimen and the margins sampled and may serve as a beneficial tool for communication amongst the multidisciplinary cancer care team.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:191-197, 2024.

Flavinated SDHA underlies the change in intrinsic optical properties of oral cancers

The molecular basis of reduced autofluorescence in oral squamous cell carcinoma (OSCC) cells relative to normal cells has been speculated to be due to lower levels of free flavin adenine dinucleotide (FAD). This speculation, along with differences in the intrinsic optical properties of extracellular collagen, lies at the foundation of the design of currently-used clinical optical detection devices. Here, we report that free FAD levels may not account for differences in autofluorescence of OSCC cells, but that the differences relate to FAD as a co-factor for flavination. Autofluorescence from a 70 kDa flavoprotein, succinate dehydrogenase A (SDHA), was found to be responsible for changes in optical properties within the FAD spectral region, with lower levels of flavinated SDHA in OSCC cells. Since flavinated SDHA is required for functional complexation with succinate dehydrogenase B (SDHB), decreased SDHB levels were observed in human OSCC tissue relative to normal tissues. Accordingly, the metabolism of OSCC cells was found to be significantly altered relative to normal cells, revealing vulnerabilities for both diagnosis and targeted therapy. Optimizing non-invasive tools based on optical and metabolic signatures of cancers will enable more precise and early diagnosis leading to improved outcomes in patients.

EGFR-targeted fluorescence molecular imaging for intraoperative margin assessment in oral cancer patients: a phase II trial

Inadequate surgical margins occur frequently in oral squamous cell carcinoma surgery. Fluorescence molecular imaging (FMI) has been explored for intraoperative margin assessment, but data are limited to phase-I studies. In this single-arm phase-II study (NCT03134846), our primary endpoints were to determine the sensitivity, specificity and positive predictive value of cetuximab-800CW for tumor-positive margins detection. Secondary endpoints were safety, close margin detection rate and intrinsic cetuximab-800CW fluorescence. In 65 patients with 66 tumors, cetuximab-800CW was well-tolerated. Fluorescent spots identified in the surgical margin with signal-to-background ratios (SBR) of ≥2 identify tumor-positive margins with 100% sensitivity, 85.9% specificity, 58.3% positive predictive value, and 100% negative predictive value. An SBR of ≥1.5 identifies close margins with 70.3% sensitivity, 76.1% specificity, 60.5% positive predictive value, and 83.1% negative predictive value. Performing frozen section analysis aimed at the fluorescent spots with an SBR of ≥1.5 enables safe, intraoperative adjustment of surgical margins.

Identification of Degenerated Murine Facial Nerves With Fluorescence Labeling After Transection Injury

OBJECTIVE

Delayed peripheral nerve repair is complicated by nerve degeneration and atrophy that can prevent identification. We use a murine facial nerve transection model to demonstrate the efficacy of ALM-488 (bevonescein) in labeling degenerated facial nerves with quantitative image analysis and qualitative survey data.

STUDY DESIGN

Prospective cohort study.

SETTING

Laboratory.

METHODS

Ten wild-type mice underwent transection of the lower facial nerve division with subsequent degeneration. Either 9 (n = 5 mice) or 12 (n = 5 mice) weeks later, mice underwent intravenous infusion of ALM-488 with in vivo real-time fluorescence imaging (FL) of the facial nerve. Using ImageJ, the mean gray value of each nerve segment under white light reflectance (WLR) and FL was compared to that of adjacent soft tissue to calculate the signal-to-background ratio (SBR). A survey was distributed to evaluate the perceived utility of ALM-488 in surgeon identification of degenerated nerves.

RESULTS

The mean SBR of degenerated nerves was 1.08 (standard deviation [SD]: 0.07) under WLR and 2.11 (SD: 0.31) under FL (p < 0.001). In mice with degenerated nerves, survey participants identified on average 3.01 (SD: 1.84) nerve branches under WLR and 5.73 (SD: 1.88) under FL (p < 0.0001). Under FL, 47 of 48 survey responses correctly identified isolated, degenerated nerves; in contrast, only 12 responses identified degenerated nerves under WLR (p < 0.0001).

CONCLUSION

Preoperative intravenous infusion of ALM-488 with FL improves the identification of degenerated facial nerves. ALM-488 also improves surgeon confidence in nerve identification, particularly in degenerated nerve branches that are not visible with WLR.

Flavinated SDHA Underlies the Change in Intrinsic Optical Properties of Oral Cancers

The molecular basis of reduced autofluorescence in oral squamous cell carcinoma (OSCC) cells relative to normal cells has been speculated to be due to lower levels of free flavin adenine dinucleotide (FAD). This speculation, along with differences in the intrinsic optical properties of extracellular collagen, lie at the foundation of the design of currently-used clinical optical detection devices. Here, we report that free FAD levels may not account for differences in autofluorescence of OSCC cells, but that the differences relate to FAD as a co-factor for flavination. Autofluorescence from a 70 kDa flavoprotein, succinate dehydrogenase A (SDHA), was found to be responsible for changes in optical properties within the FAD spectral region with lower levels of flavinated SDHA in OSCC cells. Since flavinated SDHA is required for functional complexation with succinate dehydrogenase B (SDHB), decreased SDHB levels were observed in human OSCC tissue relative to normal tissues. Accordingly, the metabolism of OSCC cells was found to be significantly altered relative to normal cells, revealing vulnerabilities for both diagnosis and targeted therapy. Optimizing non-invasive tools based on optical and metabolic signatures of cancers will enable more precise and early diagnosis leading to improved outcomes in patients.

Comprehensive Surface Histology of Fresh Resection Margins With Rapid Open-Top Light-Sheet (OTLS) Microscopy

OBJECTIVE

For tumor resections, margin status typically correlates with patient survival but positive margin rates are generally high (up to 45% for head and neck cancer). Frozen section analysis (FSA) is often used to intraoperatively assess the margins of excised tissue, but suffers from severe under-sampling of the actual margin surface, inferior image quality, slow turnaround, and tissue destructiveness.

METHODS

Here, we have developed an imaging workflow to generate en face histologic images of freshly excised surgical margin surfaces based on open-top light-sheet (OTLS) microscopy. Key innovations include (1) the ability to generate false-colored H&E-mimicking images of tissue surfaces stained for < 1 min with a single fluorophore, (2) rapid OTLS surface imaging at a rate of 15 min/cm2 followed by real-time post-processing of datasets within RAM at a rate of 5 min/cm2, and (3) rapid digital surface extraction to account for topological irregularities at the tissue surface.

RESULTS

In addition to the performance metrics listed above, we show that the image quality generated by our rapid surface-histology method approaches that of gold-standard archival histology.

CONCLUSION

OTLS microscopy has the feasibility to provide intraoperative guidance of surgical oncology procedures.

SIGNIFICANCE

The reported methods can potentially improve tumor-resection procedures, thereby improving patient outcomes and quality of life.

Determination of Flap Survival Isolated From Wound Bed Vasculature Using a Murine Axial Flap Model

Background: Axial pattern flaps are a common reconstructive option following resection of soft tissue malignancies. We determine the early dependence of an axial flap on wound bed vasculature by isolating the underlying wound bed and depriving contact with the overlying flap. Materials and Methods: Mice were divided into 5 groups: No silicone (n = 7), silicone in the proximal 50% of the wound bed (n = 8), silicone in the distal 50% of the wound bed (n = 5), silicone over the full length of the wound bed with pedicle preservation (n = 5), and silicone over the full length of the wound bed with pedicle sacrifice (n = 5). The pedicle was the lateral thoracic artery. Daily photographs were taken, and the percent of viable flap was determined using ImageJ© software (public domain JAVA image processing program, National Institute of Health, Bethesda, MA). Percent flap viability for each group was compared to the no silicone group, which acted as the reference. Results: Mean differences in percent flap necrotic area (with 95% confidence interval) compared to the no silicone group were -0.15% (-15.09 to 14.09), 2.07% (-5.26 to 9.39), 2.98% (-10.98 to 16.94), and 14.21% (0.48 to 27.94) for the full-length silicone with preserved pedicle, proximal silicone, distal silicone, and full-length silicone with sacrificed pedicle groups, respectively. The full-length silicone with sacrificed pedicle group had a significant difference in flap viability (P = .045) compared to the no silicone group. Conclusion: We investigate the role of the wound bed vasculature in a murine axial flap model and demonstrate that the wound bed vasculature is not essential for early distal flap survival.

WPOI-5: Accurately Identified at Intraoperative Consultation and Predictive of Occult Cervical Metastases

BACKGROUND

Frozen section analysis of oral cancer specimens is ideal for assessing margin distances and depth of invasion (DOI); the latter impacts intraoperative decisions regarding elective neck dissection (END). Here, we show that intraoperative determination of worst pattern of invasion (WPOI), specifically WPOI-5, has a high level of accuracy. This relates to our demonstration herein that WPOI-5 predicts occult cervical metastases (OCM) for pT1 oral squamous carcinoma (OSC).

METHODS

The presence of OCM was correlated with WPOI in 228 patients with primary T1/T2/cN0 OSC undergoing resection and END. Concordance between intraoperative and final pathology WPOI determination was assessed on 51 cases of OSC.

RESULTS

WPOI-5 predicts OCM in pT1 patients, compared with WPOI-4/WPOI-3 (p < 0.0001). Most pT1 WPOI-5 tumors had DOI of 4-5 mm (24/59 or 40.7%). Only two pT1 WPOI-5 tumors had DOI < 4 mm (3.0 and 3.5 mm). If END were performed in this pT1 cohort for all WPOI-5 OSC patients regardless of DOI, OR all OSC patients with DOI ≥ 4 mm regardless of WPOI, then no OCM would be missed (p = 0.017, 100% sensitivity, 29% specificity, 77% positive predictive value, 23% negative predictive value). With respect to intraoperative WPOI-5 determination, the accuracy, sensitivity, and specificity was 92.16, 73.33, and 100.0%, respectively.

CONCLUSIONS

DOI ≥ 4 mm is the dominant predictor of OCM. For the rare WPOI-5 OSC with DOI < 4 mm, it is reasonable to suggest that surgeons perform END. WPOI-5 may be accurately determined intraoperatively. As microscopic instruction is needed to accurately assess WPOI-5, a teaching link is included in this manuscript.

Fluorescence guidance improves the accuracy of radiological imaging-guided surgical navigation

BACKGROUND

Imaging-based navigation technologies require static referencing between the target anatomy and the optical sensors. Imaging-based navigation is therefore well suited to operations involving bony anatomy; however, these technologies have not translated to soft-tissue surgery. We sought to determine if fluorescence imaging complement conventional, radiological imaging-based navigation to guide the dissection of soft-tissue phantom tumors.

METHODS

Using a human tissue-simulating model, we created tumor phantoms with physiologically accurate optical density and contrast concentrations. Phantoms were dissected using all possible combinations of computed tomography (CT), magnetic resonance, and fluorescence imaging; controls were included. The data were margin accuracy, margin status, tumor spatial alignment, and dissection duration.

RESULTS

Margin accuracy was higher for combined navigation modalities compared to individual navigation modalities, and accuracy was highest with combined CT and fluorescence navigation (p = 0.045). Margin status improved with combined CT and fluorescence imaging.

CONCLUSIONS

At present, imaging-based navigation has limited application in guiding soft-tissue tumor operations due to its inability to compensate for positional changes during surgery. This study indicates that fluorescence guidance enhances the accuracy of imaging-based navigation and may be best viewed as a synergistic technology, rather than a competing one.

The Evolution of Fluorescence-Guided Surgery

There has been continual development of fluorescent agents, imaging systems, and their applications over the past several decades. With the recent FDA approvals of 5-aminolevulinic acid, hexaminolevulinate, and pafolacianine, much of the potential that fluorescence offers for image-guided oncologic surgery is now being actualized. In this article, we review the evolution of fluorescence-guided surgery, highlight the milestones which have contributed to successful clinical translation, and examine the future of targeted fluorescence imaging.

The computer-aided design margin: Ex vivo 3D specimen mapping to improve communication between surgeons and pathologists

BACKGROUND

Numerous challenges exist in determining surgical margin status. Communication between surgeons and pathologists is crucial for specimen orientation and accurate margin assessment.

METHODS

A prospective study to determine feasibility of incorporating three-dimensional (3D) scanning into surgical pathology workflow was performed. A structured-light 3D scanner captured the photorealistic surface topography of fresh surgical specimens. Computer-aided design (CAD) software was used to document sites of margin sampling and sectioning. Surveys were distributed among faculty and staff stakeholders to assess feasibility.

RESULTS

A series of 40 cases were 3D-scanned. Median image acquisition time was 8 min. The majority of respondents agreed that the experimental 3D system helped achieve clearer communication. 3D specimen maps assisted in the communication of a focally positive or close margin in 4 of 17 cases.

CONCLUSIONS

Routine 3D scanning and specimen mapping is feasible and represents an innovative approach to intraoperative and final pathology documentation, margin analysis, and surgeon-pathologist communication.

Preclinical feasibility of robot-assisted sentinel lymph node biopsy using multi-modality magnetic and fluorescence guidance in the head and neck

BACKGROUND

Sentinel lymph node biopsy (SLNB) is a staging procedure dependent on accurate mapping of draining lymphatics via tracers. Robot-assisted SLNB enables access to multiple neck levels with a single incision and intraoperative fluorescence guidance to the SLN.

METHODS

Lymphatic mapping in swine was done using a magnetic tracer and fluorescent dye, injected into the tongue. MRI preoperatively mapped lymphatic spread of the magnetic tracer. Dissection was performed using a da Vinci Xi robot guided by fluorescence-imaging of the dye.

RESULTS

Robot-assisted SLNB was successfully performed in all animals (n = 5). A novel MRI protocol differentiated SLNs (n = 6) from lower echelon nodes (n = 11) based on flow progression. Fluorescence imaging provided valuable intraoperative guidance and correlated with magnetic-positive nodes.

CONCLUSIONS

This study demonstrates preclinical feasibility of a robot-assisted approach to SLNB using magnetic and fluorescent tracers in the head and neck, enabling both preoperative mapping and intraoperative guidance.

In vivo visualization and molecular targeting of the cardiac conduction system

Accidental injury to the cardiac conduction system (CCS), a network of specialized cells embedded within the heart and indistinguishable from the surrounding heart muscle tissue, is a major complication in cardiac surgeries. Here, we addressed this unmet need by engineering targeted antibody-dye conjugates directed against the CCS, allowing for the visualization of the CCS in vivo following a single intravenous injection in mice. These optical imaging tools showed high sensitivity, specificity, and resolution, with no adverse effects on CCS function. Further, with the goal of creating a viable prototype for human use, we generated a fully human monoclonal Fab that similarly targets the CCS with high specificity. We demonstrate that, when conjugated to an alternative cargo, this Fab can also be used to modulate CCS biology in vivo, providing a proof of principle for targeted cardiac therapeutics. Finally, in performing differential gene expression analyses of the entire murine CCS at single-cell resolution, we uncovered and validated a suite of additional cell surface markers that can be used to molecularly target the distinct subcomponents of the CCS, each prone to distinct life-threatening arrhythmias. These findings lay the foundation for translational approaches targeting the CCS for visualization and therapy in cardiothoracic surgery, cardiac imaging, and arrhythmia management.

89Zr-panitumumab Combined With 18F-FDG PET Improves Detection and Staging of Head and Neck Squamous Cell Carcinoma

PURPOSE

Determine the safety and specificity of a tumor-targeted radiotracer (89Zr-pan) in combination with 18F-FDG PET/CT to improve diagnostic accuracy in head and neck squamous cell carcinoma (HNSCC).

EXPERIMENTAL DESIGN

Adult patients with biopsy-proven HNSCC scheduled for standard-of-care surgery were enrolled in a clinical trial and underwent systemic administration of 89Zirconium-panitumumab and panitumumab-IRDye800 followed by preoperative 89Zr-pan PET/CT and intraoperative fluorescence imaging. The sensitivity, specificity, and AUC were evaluated.

RESULTS

A total of fourteen patients were enrolled and completed the study. Four patients (28.5%) had areas of high 18F-FDG uptake outside the head and neck region with maximum standardized uptake values (SUVmax) greater than 2.0 that were not detected on 89Zr-pan PET/CT. These four patients with incidental findings underwent further workup and had no evidence of cancer on biopsy or clinical follow-up. Forty-eight lesions (primary tumor, LNs, incidental findings) with SUVmax ranging 2.0-23.6 were visualized on 18F-FDG PET/CT; 34 lesions on 89Zr-pan PET/CT with SUVmax ranging 0.9-10.5. The combined ability of 18F-FDG PET/CT and 89Zr-pan PET/CT to detect HNSCC in the whole body was improved with higher specificity of 96.3% [confidence interval (CI), 89.2%-100%] compared to 18F-FDG PET/CT alone with specificity of 74.1% (CI, 74.1%-90.6%). One possibly related grade 1 adverse event of prolonged QTc (460 ms) was reported but resolved in follow-up.

CONCLUSIONS

89Zr-pan PET/CT imaging is safe and may be valuable in discriminating incidental findings identified on 18F-FDG PET/CT from true positive lesions and in localizing metastatic LNs.

A real-time GPU-accelerated parallelized image processor for large-scale multiplexed fluorescence microscopy data

Highly multiplexed, single-cell imaging has revolutionized our understanding of spatial cellular interactions associated with health and disease. With ever-increasing numbers of antigens, region sizes, and sample sizes, multiplexed fluorescence imaging experiments routinely produce terabytes of data. Fast and accurate processing of these large-scale, high-dimensional imaging data is essential to ensure reliable segmentation and identification of cell types and for characterization of cellular neighborhoods and inference of mechanistic insights. Here, we describe RAPID, a Real-time, GPU-Accelerated Parallelized Image processing software for large-scale multiplexed fluorescence microscopy Data. RAPID deconvolves large-scale, high-dimensional fluorescence imaging data, stitches and registers images with axial and lateral drift correction, and minimizes tissue autofluorescence such as that introduced by erythrocytes. Incorporation of an open source CUDA-driven, GPU-assisted deconvolution produced results similar to fee-based commercial software. RAPID reduces data processing time and artifacts and improves image contrast and signal-to-noise compared to our previous image processing pipeline, thus providing a useful tool for accurate and robust analysis of large-scale, multiplexed, fluorescence imaging data.

Fluorescent Molecular Imaging Can Improve Intraoperative Sentinel Margin Detection in Oral Squamous Cell Carcinoma

In head and neck cancer, a major limitation of current intraoperative margin analysis is the ability to detect areas most likely to be positive based on specimen palpation, especially for larger specimens where sampling error limits detection of positive margins. This study aims to prospectively examine the clinical value of fluorescent molecular imaging to accurately identify "the sentinel margin," the point on a specimen at which the tumor lies closest to the resected edge in real-time during frozen section analysis. Methods: Eighteen patients with oral squamous cell carcinoma were enrolled into a prospective clinical trial and infused intravenously with 50 mg of panitumumab-IRDye800CW 1-5 d before surgery. Resected specimens were imaged in a closed-field near-infrared optical imaging system in near real-time, and custom-designed software was used to identify locations of highest fluorescence on deep and peripheral margins. The surgeon identified the sentinel margin masked to optical specimen mapping, and then the regions of highest fluorescence were identified and marked for frozen analysis. Final pathology based on specimen reconstruction was used as reference standard. Results: Resected specimens were imaged in the operating room, and fluorescence had a higher interobserver agreement with pathology (Cohen κ value 0.96) than the surgeon (Cohen κ value of 0.82) for the location of the closest margin. Plotting margin distance at the predicted sentinel margin location of each observer versus the actual closest margin distance at pathology demonstrated best correlation between fluorescence and pathology (R² = 0.98) with surgeon (R² = 0.75). Conclusion: Fluorescence imaging can improve identification of the sentinel margin in head and neck cancer resections, holding promise for rapid identification of positive margins and improved oncologic outcomes.

Noninvasive ultrasonic induction of cerebrospinal fluid flow enhances intrathecal drug delivery

Intrathecal drug delivery is routinely used in the treatment and prophylaxis of varied central nervous system conditions, as doing so allows drugs to directly bypass the blood-brain barrier. However, the utility of this route of administration is limited by poor brain and spinal cord parenchymal drug uptake from the cerebrospinal fluid. We demonstrate that a simple noninvasive transcranial ultrasound protocol can significantly increase influx of cerebrospinal fluid into the perivascular spaces of the brain, to enhance the uptake of intrathecally administered drugs. Specifically, we administered small (~1 kDa) and large (~155 kDa) molecule agents into the cisterna magna of rats and then applied low, diagnostic-intensity focused ultrasound in a scanning protocol throughout the brain. Using real-time magnetic resonance imaging and ex vivo histologic analyses, we observed significantly increased uptake of small molecule agents into the brain parenchyma, and of both small and large molecule agents into the perivascular space from the cerebrospinal fluid. Notably, there was no evidence of brain parenchymal damage following this intervention. The low intensity and noninvasive approach of transcranial ultrasound in this protocol underscores the ready path to clinical translation of this technique. In this manner, this protocol can be used to directly bypass the blood-brain barrier for whole-brain delivery of a variety of agents. Additionally, this technique can potentially be used as a means to probe the causal role of the glymphatic system in the variety of disease and physiologic processes to which it has been correlated.

Validation of a surgical training model containing indocyanine green for near‐infrared fluorescence imaging

Objective

To determine the efficacy of a surgical training model for fluorescence‐guided cancer surgery and validate its utility to detect any residual tumors after tumor resection using electrocautery.

Methods

We developed surgical training models containing indocyanine green (ICG) for near‐infrared (NIR) fluorescence imaging using a root vegetable organic material (konjac). After the fluorescence assessment for the models, the surgical simulation for fluorescence‐guided cancer surgery using electrocautery was performed. ICG‐containing tumors were divided into two surgical groups: “Enucleation” (removal of the entire visible tumor) and “Complete resection” (removal of the tumor with an appropriate 5‐mm surgical margin).

Results

All 12 ICG‐containing tumors were clearly visible from the normal view but not from the flipped view. The tumor resection time was significantly longer in the “Complete resection” group than in the “Enucleation” group (p < .001). The ICG‐containing tumors showed a high tumor‐to background ratio from the normal (average = 45.8) and flipped (average = 19.2) views, indicating that the models including ICG‐containing tumors were useful for a surgical simulation in fluorescence‐guided surgery. The average mean fluorescence intensity of the wound bed was significantly higher in the “Enucleation” group than in the “Complete resection” group (p < .01). No decrease in fluorescence signal was found in the wound bed even at 2 days postresection.

Conclusion

Our surgical training model containing a fluorescent agent is safe, inexpensive, not harmful for humans, and easy to dispose after use. Our model would be beneficial for surgeons to learn NIR fluorescence imaging and to accelerate fluorescence‐guided cancer surgery into clinical application.

The Use of Panitumumab-IRDye800CW in a Novel Murine Model for Conjunctival Squamous Cell Carcinoma

Purpose

Conjunctival squamous cell carcinoma (SCC) is a sight-threatening ocular surface malignancy with the primary treatment modality being surgical resection. To evaluate surgical imaging modalities to improve surgical resection, we established a novel murine model for conjunctival SCC to demonstrate the utility of panitumumab-IRDye800, a fluorescently labeled anti-epidermal growth factor receptor (EGFR) antibody.

Methods

NOD-scid IL2Rgamma^null (NSG) mice received subconjunctival injection of UM-SCC-1 or SCC-9, head and neck SCC cell lines. On tumor growth, mice were injected with Panitumumab-IRDye800CW, and imaged with a small animal imaging system and optical coherence tomography (OCT). Immunohistochemistry for SCC markers were used to confirm tumor origin.

Results

Seventy-five percent (N = 4) of the UM-SCC-1 group developed aggressive, rapidly growing tumors that were P40 and EGFR positive within two weeks of inoculation. The SCC-9 tumors failed to demonstrate any growth (N = 4). Ocular tumors demonstrated high fluorescence levels with a tumor to background ratio of 3.8.

Conclusions

Subconjunctival injections are an appropriate technique to create in vivo models for assessing treatment modalities and novel therapies in conjunctival SCC.

Translational Relevance

This model demonstrates Panitumumab-IRDye800CW's utility in the ophthalmic setting and suggests that clinical trials may be warranted.

First Clinical Results of Fluorescence Lifetime-enhanced Tumor Imaging Using Receptor-targeted Fluorescent Probes

PURPOSE

Fluorescence molecular imaging, using cancer-targeted near infrared (NIR) fluorescent probes, offers the promise of accurate tumor delineation during surgeries and the detection of cancer specific molecular expression in vivo. However, nonspecific probe accumulation in normal tissue results in poor tumor fluorescence contrast, precluding widespread clinical adoption of novel imaging agents. Here we present the first clinical evidence that fluorescence lifetime (FLT) imaging can provide tumor specificity at the cellular level in patients systemically injected with panitumumab-IRDye800CW, an EGFR-targeted NIR fluorescent probe.

EXPERIMENTAL DESIGN

We performed wide-field and microscopic FLT imaging of resection specimens from patients injected with panitumumab-IRDye800CW under an FDA directed clinical trial.

RESULTS

We show that the FLT within EGFR-overexpressing cancer cells is significantly longer than the FLT of normal tissue, providing high sensitivity (>98%) and specificity (>98%) for tumor versus normal tissue classification, despite the presence of significant nonspecific probe accumulation. We further show microscopic evidence that the mean tissue FLT is spatially correlated (r > 0.85) with tumor-specific EGFR expression in tissue and is consistent across multiple patients. These tumor cell-specific FLT changes can be detected through thick biological tissue, allowing highly specific tumor detection and noninvasive monitoring of tumor EFGR expression in vivo.

CONCLUSIONS

Our data indicate that FLT imaging is a promising approach for enhancing tumor contrast using an antibody-targeted NIR probe with a proven safety profile in humans, suggesting a strong potential for clinical applications in image guided surgery, cancer diagnostics, and staging.

Factors for differential outcome across cancers in clinical molecular-targeted fluorescence imaging

Clinical imaging performance using a fluorescent antibody was compared across three cancers to elucidate physical and biological factors contributing to differential translation of epidermal growth factor receptor (EGFR) expression to macroscopic fluorescence in tumors. Methods: Thirty-one patients with high-grade glioma (HGG, n = 5), head-and-neck squamous cell carcinoma (HNSCC, n = 23) or lung adenocarcinoma (LAC, n = 3) were systemically infused with 50 mg panitumumab-IRDye800, 1 - 3 days prior to surgery. Intraoperative open-field fluorescent images of the surgical field were acquired, where imaging device settings and operating room lighting conditions were tested on tissue-mimicking phantoms. Fluorescence contrast and margin size were measured on resected specimen surface. Antibody distribution and EGFR immunoreactivity were characterized in macroscopic and microscopic histological structures. Integrity of the blood-brain barrier (BBB) was examined via tight junction protein (claudin-5) expression with immunohistochemistry. Stepwise multivariate linear regression of biological variables was performed to identify independent predictors of panitumumab-IRDye800 concentration in tissue. Results: Optimally acquired at the lowest gain for tumor detection with ambient light, intraoperative fluorescence imaging enhanced tissue-size dependent tumor contrast by 5.2-fold, 3.4-fold and 1.4-fold in HGG, HNSCC and LAC, respectively. Tissue surface fluorescence target-to-background ratio correlated with margin size and identified 78 - 97% of at-risk resection margins ex vivo. In 4 µm-thick tissue sections, fluorescence detected tumor with 0.85 - 0.89 areas under the receiver operating characteristic curves. Preferential breakdown of BBB in HGG improved tumor specificity of intratumoral antibody distribution relative to that of EGFR (96% vs 80%) despite its reduced concentration (3.9 ng/mg tissue) compared to HNSCC (8.1 ng/mg) and LAC (6.3 ng/mg). Cellular EGFR expression, tumor cell density, plasma antibody concentration and delivery barrier were independently associated with local intratumoral panitumumab-IRDye800 concentration with 0.62 goodness-of-fit of prediction. Conclusion: In multi-cancer clinical imaging of receptor-ligand based molecular probe, plasma antibody concentration, delivery barrier, as well as intratumoral EGFR expression driven by cellular biomarker expression and tumor cell density, led to heterogeneous intratumoral antibody accumulation and spatial distribution while tumor size, resection margin, and intraoperative imaging settings substantially influenced macroscopic tumor contrast.

Epidermal growth factor-targeted fluorescence is unaffected by standard neoadjuvant therapies in human sarcomas

Curative surgery for other many cancers requires that the tumor be removed with a zone of normal tissue surrounding the tumor with 'negative' margins. Sarcomas, cancers of the bones, muscles, and fat, require WLE for cure. Unfortunately, 'positive' margins occur in 20-25% of sarcoma surgeries, associated with cancer recurrence and reduced survival. Our group successfully tested a small-molecule fluorophore (ABY-029) in sarcomas that targets the epidermal growth factor receptor. We sought to evaluate human sarcoma xenografts for epidermal growth factor receptor expression and binding of ABY-029 with and without exposure to standard presurgical chemotherapy and radiation. We inoculated groups of 24 NSG mice with five cell lines (120 mice total). Eight mice from each cell line received: 1) radiation alone; 2) chemotherapy alone; or 3) chemotherapy and radiation. We administered ABY-029 2-4 hours before surgery. Tumor and biopsy portions of background tissues were removed. All tissues were imaged on a LI-COR Odyssey and processed in pathology. There were no significant reductions in epidermal growth factor receptor expression or in ABY-029-mediated fluorescence in tumors exposed to chemotherapy, radiation, or both. fluorescence-guided surgery demonstrates strong promise to improve curative surgical cancer care, particularly for sarcomas where the positive margin rate is substantial. Fluorophore performance must be evaluated under circumstances that duplicate accurately the biological milieu relevant to a particular cancer. This work shows that human sarcoma xenografts subjected to standard therapies do not demonstrate a change in epidermal growth factor receptor expression or in epidermal growth factor receptor-targeted fluorescence, thereby indicating that epidermal growth factor receptor-targeted fluorescence-guided surgery should be feasible under normal therapeutic conditions in the clinic.

Hyperintensity of integrin-targeted fluorescence agent IntegriSense750 accurately predicts flap necrosis compared to Indocyanine green

BACKGROUND

Flap necrosis is a feared complication of reconstructive surgery. Current methods of prediction using Indocyanine green (ICG) lack specificity. IntegriSense750 is a fluorescence agent that binds sites of vascular remodeling. We hypothesized that IntegriSense750 better predicts flap compromise compared to ICG.

METHODS

Fifteen mice underwent lateral thoracic artery axial flap harvest. Mice received an injection of ICG (n = 7) or IntegriSense750 (n = 8) daily from postoperative days (POD) 0-3 and were imaged daily. Mean signal-to-background ratios quantified the change in fluorescence as necrosis progressed.

RESULTS

Mean signal-to-background ratio was significantly higher for IntegriSense750 compared to ICG on POD0 (1.47 ± 0.17 vs. 0.86 ± 0.21, p = 0.01) and daily through POD3 (2.12 ± 0.70 vs. 0.96 ± 0.29, p < 0.001).

CONCLUSIONS

IntegriSense750 demonstrates increased signal-to-background ratio at areas of flap distress compared to ICG which may increase identification of flap necrosis and improve patient outcomes.

A Scoping Review of Ongoing Fluorescence-Guided Surgery Clinical Trials in Otolaryngology

OBJECTIVE

Fluorescence-guided surgery (FGS) is a rapidly developing intraoperative technology, and many contrast agents are currently under investigation. We sought to provide a review of the current state of FGS clinical trials in Otolaryngology, emphasizing its oncologic applications.

METHODS

According to the preferred reporting Items for systematic reviews and meta-analyses (PRISMA) workflow for scoping reviews, a clinical trial search was performed across multiple international clinical trials registries, searching for permutations of "fluorescence," "tumor," "surgery," and "nerve" to identify all relevant studies. Studies that were active, enrolling, or soon to be enrolling patients undergoing head and neck surgery were included.

RESULTS

Nineteen studies were eligible for inclusion. Seventeen studies are focused on FGS for oncologic resection and lymph node detection. One study assesses peripheral nerve fluorescence, and one evaluates normal parathyroid function after thyroidectomy. Contrast agents under development are conjugated to fluorophores that excite in the 800 nm (indocyanine green), 410 nm (5-aminolevulinic acid), 700 nm (Cyanine 5.5), and 525 nm ranges (fluorescein derivatives).

CONCLUSION

Presently, there are 19 ongoing trials investigating novel FGS contrast agents for their safety, efficacy, and utility in Otolaryngology-Head and Neck Surgery. These agents rely on unique fluorophores and absorption ranges in the near-infrared and visible light spectra. FGS studies are expanding within Otolaryngology-Head and Neck Surgery with profound implications in oncologic surgery, lymph node detection, and anatomic and functional assessment. Laryngoscope, 2021.

A narrative review of fluorescence imaging in robotic-assisted surgery

Objective

In this review, we provide examples of applications of fluorescence imaging in urologic, gynecologic, general, and endocrine surgeries.

Background

While robotic-assisted surgery has helped increase the availability of minimally invasive procedures across surgical specialties, there remains an opportunity to reduce adverse events associated with open, laparoscopic, and robotic-assisted methods. In 2011, fluorescence imaging was introduced as an option to the da Vinci Surgical System, and has been standard equipment since 2014. Without interfering with surgical workflow, this fluorescence technology named Firefly^® allows for acquisition and display of near-infrared fluorescent signals that are co-registered with white light endoscopic images. As a result, robotic surgeons of all specialties have been able to explore the clinical utility of fluorescence guided surgery.

Methods

Literature searches were performed using the PubMed and MEDLINE databases using the keywords "robotic-assisted fluorescence surgery", "ICG robotic surgery", and "fluorescence guided surgery" covering the years 2011-2020.

Conclusions

Real-time intraoperative fluorescence guidance has shown great potential in helping guide surgeons in both simple and complex surgical interventions. Indocyanine green is one of the most widely-used imaging agents in fluorescence guided surgery, and other targeted, near-infrared imaging agents are in various stages of development. Fluorescence is becoming a reliable tool that can help surgeons in their decision-making process in some specialties, while explorations continue in others.

Metastatic and sentinel lymph node mapping using intravenously delivered Panitumumab-IRDye800CW

Rationale: Sentinel lymph node biopsy (SLNB) is a well-established minimally invasive staging procedure that maps the spread of tumour metastases from their primary site to the regional lymphatics. Currently, the procedure requires the local peri-tumoural injection of radiolabelled and/or optical agents, and is therefore operator dependent, disruptive to surgical workflow and restricted largely to a small subset of malignancies that can be readily accessed externally for local tracer injection. The present study set out to determine whether intravenous (IV) infusion of a tumor-targeted tracer could identify sentinel and metastatic lymph nodes (LNs) in order to overcome these limitations. Methods: We examined 27 patients with oral squamous cell carcinoma (OSCC), 18 of whom were clinically node negative (cN0). Patients were infused intravenously with 50mg of Panitumumab-IRDye800CW prior to surgical resection of their primary tumour with neck dissection and/or SLNB. Lymphadenectomy specimens underwent fluorescence molecular imaging to evaluate tracer distribution to LNs. Results: A total of 960 LNs were analysed, of which 34 (3.5%) contained metastatic disease. Panitumumab-IRDye800CW preferentially localized to metastatic and sentinel LNs as evidenced by a higher fluorescent signal relative to other lymph nodes. The median MFI of metastatic LNs was significantly higher than the median MFI of benign LNs (0.06 versus 0.02, p < 0.05). Furthermore, selecting the highest five fluorescence intensity LNs from individual specimens resulted in 100% sensitivity, 85.8% specificity and 100% negative predictive value (NPV) for the detection of occult metastases and 100% accuracy for clinically staging the neck. In the cN+ cohort, assessment of the highest 5 fluorescence LNs per patient had 87.5% sensitivity, 93.2% specificity and 99.1% NPV for the detection of metastatic nodes. Conclusion: When intravenously infused, a tumour-targeted tracer localized to sentinel and metastatic lymph nodes. Further validation of an IV tumor-targeted tracer delivery approach for SLNB could dramatically change the practice of SLNB, allowing its application to other malignancies where the primary tumour is not accessible for local tracer injection.

EGFR-targeted intraoperative fluorescence imaging detects high-grade glioma with panitumumab-IRDye800 in a phase 1 clinical trial

Rationale: First-line therapy for high-grade gliomas (HGGs) includes maximal safe surgical resection. The extent of resection predicts overall survival, but current neuroimaging approaches lack tumor specificity. The epidermal growth factor receptor (EGFR) is a highly expressed HGG biomarker. We evaluated the safety and feasibility of an anti-EGFR antibody, panitumuab-IRDye800, at subtherapeutic doses as an imaging agent for HGG. Methods: Eleven patients with contrast-enhancing HGGs were systemically infused with panitumumab-IRDye800 at a low (50 mg) or high (100 mg) dose 1-5 days before surgery. Near-infrared fluorescence imaging was performed intraoperatively and ex vivo, to identify the optimal tumor-to-background ratio by comparing mean fluorescence intensities of tumor and histologically uninvolved tissue. Fluorescence was correlated with preoperative T1 contrast, tumor size, EGFR expression and other biomarkers. Results: No adverse events were attributed to panitumumab-IRDye800. Tumor fragments as small as 5 mg could be detected ex vivo and detection threshold was dose dependent. In tissue sections, panitumumab-IRDye800 was highly sensitive (95%) and specific (96%) for pathology confirmed tumor containing tissue. Cellular delivery of panitumumab-IRDye800 was correlated to EGFR overexpression and compromised blood-brain barrier in HGG, while normal brain tissue showed minimal fluorescence. Intraoperative fluorescence improved optical contrast in tumor tissue within and beyond the T1 contrast-enhancing margin, with contrast-to-noise ratios of 9.5 ± 2.1 and 3.6 ± 1.1, respectively. Conclusions: Panitumumab-IRDye800 provided excellent tumor contrast and was safe at both doses. Smaller fragments of tumor could be detected at the 100 mg dose and thus more suitable for intraoperative imaging.

Distress Screening Through Patient-Reported Outcomes Measurement Information System (PROMIS) at an Academic Cancer Center and Network Site: Implementation of a Hybrid Model

PURPOSE

Cancer care guidelines recommend regular distress screening of patients, with approximately one in three patients with cancer experiencing significant distress. However, the implementation of such programs is variable and inconsistent. We sought to assess the feasibility of implementing a hybrid electronic and paper screening tool for distress in all patients coming to a large academic cancer center and an associated integrated network site.

METHODS

Patients at an academic cancer center (Stanford Cancer Center) and its associated integrated network site received either an electronic or on-paper modified Patient-Reported Outcomes Measurement Information System-Global Health questionnaire, to assess overall health and distress. We used the Reach, Effectiveness, Adoption, Implementation, and Maintenance implementation framework to test and report on the feasibility of using this questionnaire. Iterative workflow changes were made to implement the questionnaire throughout the healthcare system, including processes to integrate with existing electronic health records.

RESULTS

From June 2015 to December 2017, 53,954 questionnaires representing 26,242 patients were collected. Approximately 30% of the questionnaires were completed before the visit on an electronic patient portal. The number of patients meeting the positive screen threshold remained around 40% throughout the study period. Following assessment, there were 3,763 referrals to cancer supportive services. Of note, those with a positive screen were more likely to have a referral to supportive care (odds ratio, 6.4; 95% CI, 5.8 to 6.9; P < .0001).

CONCLUSION

The hybrid electronic and on-paper use of a commonly available patient-reported outcome tool, Patient-Reported Outcomes Measurement Information System-Global Health, as a large-scale distress screening method, is feasible at a large integrated cancer center.

Real-time fluorescence imaging in intraoperative decision making for cancer surgery

Fluorescence-guided surgery is an intraoperative optical imaging method that provides surgeons with real-time guidance for the delineation of tumours. Currently, in phase 1 and 2 clinical trials, evaluation of fluorescence-guided surgery is primarily focused on its diagnostic performance, although the corresponding outcome variables do not inform about the added clinical benefit of fluorescence-guided surgery and are challenging to assess objectively. Nonetheless, the effect of fluorescence-guided surgery on intraoperative decision making is the most objective outcome measurement to assess the clinical value of this imaging method. In this Review, we explore the study designs of existing trials of fluorescence-guided surgery that allow us to extract information on potential changes in intraoperative decision making, such as additional or more conservative resections. On the basis of this analysis, we offer recommendations on how to report changes in intraoperative decision making that result from fluorescence imaging, which is of utmost importance for the widespread clinical implementation of fluorescence-guided surgery.

Review of successful pathways for regulatory approvals in open-field fluorescence-guided surgery

SIGNIFICANCE

The modern use of fluorescence in surgery came iteratively through new devices and pre-existing imaging agents, with indications that were paved via regulatory approvals and device clearances. These events led to a growing set of surgery subspecialty uses.

AIM

This article outlines the key milestones that initiated commercially marketed systems and agents by highlighting temporal sequences and strategic decisions between them, with the goal of helping to inform future successes.

APPROACH

A review of successful regulatory approvals and the sequences between them was completed for companies that achieved US Food and Drug Administration (FDA) premarket approval or new drug approvals (NDAs) or device clearances in the fields of fluorescent imaging agents, open surgery imaging devices, and their approved medical indications.

RESULTS

Angiography agents, indocyanine green and fluorescein, were approved for human use as absorbing dyes, and this use in retinal imaging was the precursor to lateral translation into tissue perfusion imaging in the last two decades with a growing number of devices. Many FDA cleared devices for open fluorescence-guided surgery used the predicate created by the SPY SP2000 system. This first system was 510(k) cleared for angiography imaging with a unique split predicate from x-ray imaging of vasculature and retinal fluorescence angiography. Since that time, the lateral spread of open surgery devices being cleared for new indications has been occurring with a growth of adoption in surgical subspecialties. Growth into new surgical subspecialties has been achieved by leveraging different NDAs and clearances between indications, such that medical uses have broadened over time.

CONCLUSIONS

Key decisions made by developers to advance specific device clearances and NDAs have been based upon existing optical fluorescent agents. The historical lessons and regulatory trends in newer indications and contrast agents can help the field evolve via successful investment in new systems and applications.

Intraoperative Fluorescence-Guided Surgery in Head and Neck Squamous Cell Carcinoma

The rate of positive margins in head and neck cancers has remained stagnant over the past three decades and is consistently associated with poor overall survival. This suggests that significant improvements must be made intraoperatively to ensure negative margins. We discuss the important role of fluorescence imaging to guide surgical oncology in head and neck cancer. This review includes a general overview of the principles of fluorescence, available fluorophores used for fluorescence imaging, and specific clinical applications of fluorescence-guided surgery, as well as challenges and future directions in head and neck surgical oncology. Laryngoscope, 131:529-534, 2021.

Microvascular Reconstruction of Osteonecrosis: Assessment of Long-term Quality of Life

OBJECTIVE

Review long-term clinical and quality-of-life outcomes following free flap reconstruction for osteonecrosis.

STUDY DESIGN

Retrospective multi-institutional review.

SETTING

Tertiary care centers.

METHODS

Patients included those undergoing free flap reconstructions for osteonecrosis of the head and neck (N = 232). Data included demographics, defect, donor site, radiation history, perioperative management, diet status, recurrence rates, and long-term quality-of-life outcomes. Quality-of-life outcomes were measured using the University of Washington Quality of Life (UW-QOL) survey.

RESULTS

Overall flap success rate was 91% (n = 212). Relative to preoperative diet, 15% reported improved diet function at 3 months following reconstruction and 26% at 5 years. Osteonecrosis recurred in 14% of patients (32/232); median time to onset was 11 months. Cancer recurrence occurred in 13% of patients (29/232); median time to onset was 34 months. Results from the UW-QOL questionnaire were as follows: no pain (45%), minor or no change in appearance (69%), return to baseline endurance level (37%), no limitations in recreation (40%), no changes in swallowing following reconstruction (28%), minor or no limitations in mastication (29%), minor or no speech difficulties (93%), no changes in shoulder function (84%), normal taste function (19%), normal saliva production (27%), generally excellent mood (44%), and no or minimal anxiety about cancer (94%).

CONCLUSION

The majority of patients maintained or had advancement in diet following reconstruction, with low rates of osteonecrosis or cancer recurrence and above-average scores on UW-QOL survey suggesting good return of function and quality of life.

Targeting intracranial patient-derived glioblastoma (GBM) with a NIR-I fluorescent immunoconjugate for facilitating its image-guided resection

Glioblastoma multiforme (GBM) is the most aggressive form of primary brain tumor type and is associated with a high mortality rate borne out of such affording a survival rate of only 15 months. GBM aggressiveness is associated with the overexpression of epidermal growth factor receptor (EGFR) and its mutants. Targeting GBM with therapeutics is challenging because the blood-brain barrier (BBB) permits primarily select small-molecule entities across its semipermeable blockade. However, recent preclinical data suggest that large biomolecules, such as the anti-EGFR antibody therapeutic, cetuximab, could be capable of bypassing the BBB despite the relative enormity of its size. As such, we set forth to establish the feasibility of utilizing an EGFR-targeting near-infrared-I (NIR-I) fluorescent construct in the form of an immunoconjugate (cetuxmimab-IRDye800) to achieve visual differentiation between diseased brain tissue arising from a low-passage patient-derived GBM cell line (GBM39) and healthy brain tissue via utilizing orthotopic intracranial murine GBM39 tumor models for in vivo and ex vivo evaluation such that by doing so would establish proof of concept for ultimately facilitating its in vivo fluorescence-guided resection and ex vivo surgical back-table pathological confirmation in the clinic. As anticipated, we were not capable of distinguishing between malignant tumor tissue and healthy tissue in resected intact and slices of whole brain ex vivo under white-light illumination (WLI) due to both the diseased tissue and healthy tissue appearing virtually identical to the unaided eye. However, we readily observed over an average 6-fold enhancement in the fluorescence emission in the resected intact whole brain ex vivo when performing NIR-I fluorescence imaging (FLI) on the cohort of GBM39 tumor models that were administered the immunoconjugate compared to controls. In all, we laid the initial groundwork for establishing that NIR-I fluorescent immunoconjugates (theranostics) such as cetuximab–IRDye800 can bypass the BBB to visually afford GBM39 tumor tissue differentiation for its image-guided surgical removal.

Fluorescent immunoconjugate cetuximab-IRDye800 bypasses the blood-brain-barrier to afford visualization of patient-derived GBM39 brain tumor tissue for facilitating its fluorescence-guided resection.

Co-administered antibody improves penetration of antibody-dye conjugate into human cancers with implications for antibody-drug conjugates

Poor tissue penetration remains a major challenge for antibody-based therapeutics of solid tumors, but proper dosing can improve the tissue penetration and thus therapeutic efficacy of these biologics. Due to dose-limiting toxicity of the small molecule payload, antibody-drug conjugates (ADCs) are administered at a much lower dose than their parent antibodies, which further reduces tissue penetration. We conducted an early-phase clinical trial (NCT02415881) and previously reported the safety of an antibody-dye conjugate (panitumumab-IRDye800CW) as primary outcome. Here, we report a retrospective exploratory analysis of the trial to evaluate whether co-administration of an unconjugated antibody could improve the intratumoral distribution of the antibody-dye conjugate in patients. By measuring the multiscale distribution of the antibody-dye conjugate, this study demonstrates improved microscopic antibody distribution without increasing uptake (toxicity) in healthy tissue when co-administered with the parent antibody, supporting further clinical investigation of the co-administration dosing strategy to improve the tumor penetration of ADCs.

Photoacoustic Molecular Imaging for the Identification of Lymph Node Metastasis in Head and Neck Cancer Using an Anti-EGFR Antibody-Dye Conjugate

The presence of lymph node (LN) metastases is an essential prognostic indicator in patients with head and neck squamous cell carcinoma (HNSCC). This study assessed photoacoustic molecular imaging (PAMI) of the antiepidermal growth factor receptor antibody (panitumumab) conjugated to a near-infrared fluorescent dye, IRDye800CW (panitumumab-IRDye800CW; pan800), for the identification of occult metastatic LNs in patients with HNSCC (n = 7). Methods: After in vitro photoacoustic imaging characterization of pan800, PAMI was performed on excised neck specimens from patients infused with pan800 before surgery. Freshly obtained neck specimens were imaged with 3-dimensional, multiwavelength spectroscopic PAMI (wavelengths of 680, 686, 740, 800, 860, 924, and 958 nm). Harvested LNs were then imaged with a closed-field near-infrared fluorescence imager and histologically examined by the pathologist to determine their metastatic status. Results: In total, 53 LNs with a maximum diameter of 10 mm were analyzed with photoacoustic and fluorescence imaging, of which 4 were determined to be metastatic on the final histopathologic report. Photoacoustic signals in the LNs corresponding to accumulated pan800 were spectrally unmixed using a linear least-square-error classification algorithm. The average thresholded photoacoustic signal intensity corresponding to pan800 was 5-fold higher for metastatic LNs than for benign LNs (2.50 ± 1.09 arbitrary units [a.u.] vs. 0.53 ± 0.32 a.u., P < 0.001). Fluorescence imaging showed that metastatic LNs had a 2-fold increase in fluorescence signal compared with benign LNs ex vivo (P < 0.01, 0.068 ± 0.027 a.u. vs. 0.035 ± 0.018 a.u.). Moreover, the ratio of the average of the highest 10% of the photoacoustic signal intensity over the total average, representative of the degree of heterogeneity in the pan800 signal in LNs, showed a significant difference between metastatic LNs and benign LNs (11.6 ± 13.4 vs. 1.8 ± 0.7, P < 0.01) and an area under the receiver-operating-characteristic curve of 0.96 (95% CI, 0.91-1.00). Conclusion: The data indicate that PAMI of IRDye800-labeled tumor-specific antibody may have the potential to identify occult LN metastasis perioperatively in HNSCC patients.

Safety and Stability of Antibody-Dye Conjugate in Optical Molecular Imaging

PURPOSE

The development of molecularly targeted tracers is likely to improve the accuracy of diagnostic, screening, and therapeutic tools. Despite the many therapeutic antibodies that are FDA-approved with known toxicity, only a limited number of antibody-dye conjugates have been introduced to the clinic. Thorough evaluation of the safety, stability, and pharmacokinetics of antibody conjugates in the clinical setting compared with their parental components could accelerate the clinical approval of antibodies as agents for molecular imaging. Here we investigate the safety and stability of a near-infrared fluorescent dye (IRDye800CW) conjugated panitumumab, an approved therapeutic antibody, and report on the product stability, pharmacokinetics, adverse events, and QTc interval changes in patients.

PROCEDURES

Panitumumab-IRDye800CW was made under good manufacturing practice (GMP) conditions in a single batch on March 26, 2014, and then evaluated over 4.5 years at 0, 3, and 6 months, and then at 6-month intervals thereafter. We conducted early phase trials in head and neck, lung, pancreas, and brain cancers with panitumumab-IRDye800CW. Eighty-one patients scheduled to undergo standard-of-care surgery were infused with doses between 0.06 to 2.83 mg/kg of antibody. Patient ECGs, blood samples, and adverse events were collected over 30-day post-infusion for analysis.

RESULTS

Eighty-one patients underwent infusion of the study drug at a range of doses. Six patients (7.4 %) experienced an adverse event that was considered potentially related to the drug. The most common event was a prolonged QTc interval which occurred in three patients (3.7 %). Panitumumab-IRDye800CW had two OOS results at 42 and 54 months while meeting all other stability testing criteria.

CONCLUSIONS

Panitumumab-IRDye800CW was safe and stable to administer over a 54-month window with a low rate of adverse events (7.4 %) which is consistent with the rate associated with panitumumab alone. This data supports re-purposing therapeutic antibodies as diagnostic imaging agents with limited preclinical toxicology studies.

Parotid gland metastasis in Merkel cell carcinoma of the head and neck: A series of 14 cases

Merkel cell carcinoma (MCC) is a rare cutaneous cancer of neuroendocrine cell origin that occurs frequently on the head and neck. With a high incidence of local recurrence and regional and distant metastasis, it carries a poor prognosis. We performed a retrospective study to determine the prognostic implications of parotid gland metastasis in MCC of the head and neck. Our study population was made up of 14 patients—13 men and 1 woman, aged 62 to 87 years (mean: 75.9)—who underwent a parotidectomy for the diagnosis of MCC over a period of 10 years and 9 months. Ten patients had a primary skin lesion of the head and neck and 4 presented with a parotid mass and an unknown primary. In all, 13 of the 14 patients were found to have parotid involvement—either a direct extension of MCC into the gland or a positive intraparotid lymph node; some patients had both. All patients underwent tumor excision, and 10 underwent neck dissection. Eleven patients received adjuvant radiotherapy; none received adjuvant chemotherapy. Of the 10 patients who underwent a neck dissection, 6 were found to have a cervical lymph node metastasis on pathologic examination. Follow-up ranged from 1.3 to 39.2 months (mean: 12.4). Three patients were lost to follow-up shortly after surgery, although some information was available on 2 of them. At the final follow-up, mortality data were available on 12 patients; of these, 11 had died. The lone survivor was the patient without a parotid metastasis. Among those known to have died, survival ranged from 1.6 to 49.2 months (mean: 16.0). We conclude that parotid metastasis in patients with MCC of the head and neck is associated with a dismal survival rate that is even worse than the poor survival associated with cervical node involvement.

Fluorescently Labeled Cetuximab-IRDye800 for Guided Surgical Excision of Ameloblastoma: A Proof of Principle Study

PURPOSE

Fluorescently labeled epidermal growth factor receptor (EGFR) antibodies have successfully identified microscopic tumors in multiple in vivo models of human cancers with limited toxicity. The present study sought to demonstrate the ability of fluorescently labeled anti-EGFR, cetuximab-IRDye800, to localize to ameloblastoma (AB) tumor cells in vitro and in vivo.

MATERIAL AND METHODS

EGFR expression in AB cells was confirmed by quantitative real-time polymerase chain reaction and immunohistochemistry. Primary AB cells were labeled in vitro with cetuximab-IRDye800 or nonspecific IgG-IRDye800. An in vivo patient-derived xenograft (PDX) model of AB was developed. The tumor tissue from 3 patients was implanted subcutaneously into immunocompromised mice. The mice received an intravenous injection of cetuximab-IRDye800 or IgG-IRDye800 and underwent imaging to detect infrared fluorescence using a Pearl imaging system (LI-COR Biosciences, Lincoln, NE). After resection of the overlying skin, the tumor/background ratios (TBRs) were calculated and statistically analyzed using a paired t test.

RESULTS

EGFR expression was seen in all AB samples. Tumor-specific labeling was achieved, as evidenced by a positive fluorescence signal from cetuximab-IRDye800 binding to AB cells, with little staining seen in the negative controls treated with IgG-IRDye800. In the animal PDX model, imaging revealed that the TBRs produced by cetuximab were significantly greater than those produced by IgG on days 7 to 14 for AB-20 tumors. After skin flap removal to simulate a preresection state, the TBRs increased with cetuximab and were significantly greater than the TBRs with the IgG control for PDX tumors derived from the 3 patients with AB. The excised tissues were embedded in paraffin and examined to confirm the presence of tumor.

CONCLUSIONS

Fluorescently labeled anti-EGFR demonstrated specificity for AB cells and PDX tumors. The present study is the first report of tumor-specific, antibody-based imaging of odontogenic tumors, of which AB is one of the most clinically aggressive. We expect this technology will ultimately assist surgeons treating AB by helping to accurately assess the tumor margins during surgery, leading to improved long-term local tumor control and less surgical morbidity.

Tumour-specific fluorescence-guided surgery for pancreatic cancer using panitumumab-IRDye800CW: a phase 1 single-centre, open-label, single-arm, dose-escalation study

BACKGROUND

Complete surgical resection remains the primary curative option for pancreatic ductal adenocarcinoma, with positive margins in 30-70% of patients. In this study, we aimed to evaluate the use of intraoperative tumour-specific imaging to enhance a surgeon's ability to detect visually occult cancer in real time.

METHODS

In this single-centre, open-label, single-arm study, done in the USA, we enrolled patients who had clinically suspicious or biopsy-confirmed pancreatic ductal adenocarcinomas and were scheduled for curative surgery. Eligible patients were 19 years of age or older with a life expectancy of more than 12 weeks and a Karnofsky performance status of at least 70% or an Eastern Cooperative Oncology Group or Zubrod level of one or lower, who were scheduled to undergo curative surgery. Patients were sequentially enrolled into each dosing group and 2-5 days before surgery, patients were intravenously infused with 100 mg of unlabelled panitumumab followed by 25 mg, 50 mg, or 75 mg of the near-infrared fluorescently labelled antibody (panitumumab-IRDye800CW). The primary endpoint was to determine the optimal dose of panitumumab-IRDye800CW in identifying pancreatic ductal adenocarcinomas as measured by tumour-to-background ratio in all patients. The tumour-to-background ratio was defined as the fluorescence signal of the tumour divided by the fluorescence signal of the surrounding healthy tissue. The dose-finding part of this study has been completed. This study is registered with ClinicalTrials.gov, NCT03384238.

FINDINGS

Between April, 2018, and July, 2019, 16 patients were screened for enrolment onto the study. Of the 16 screened patients, two (12%) patients withdrew from the study and three (19%) were not eligible; 11 (69%) patients completed the trial, all of whom were clinically diagnosed with pancreatic ductal adenocarcinoma. The mean tumour-to-background ratio of primary tumours was 3·0 (SD 0·5) in the 25 mg group, 4·0 (SD 0·6) in the 50 mg group, and 3·7 (SD 0·4) in the 75 mg group; the optimal dose was identified as 50 mg. Intraoperatively, near-infrared fluorescence imaging provided enhanced visualisation of the primary tumours, metastatic lymph nodes, and small (<2 mm) peritoneal metastasis. Intravenous administration of panitumumab-IRDye800CW at the doses of 25 mg, 50 mg, and 75 mg did not result in any grade 3 or higher adverse events. There were no serious adverse events attributed to panitumumab-IRDye800CW, although four possibly related adverse events (grade 1 and 2) were reported in four patients.

INTERPRETATION

To our knowledge, this study presents the first clinical use of panitumumab-IRDye800CW for detecting pancreatic ductal adenocarcinomas and shows that panitumumab-IRDye800CW is safe and feasible to use during pancreatic cancer surgery. Tumour-specific intraoperative imaging might have added value for treatment of patients with pancreatic ductal adenocarcinomas through improved patient selection and enhanced visualisation of surgical margins, metastatic lymph nodes, and distant metastasis.

FUNDING

National Institutes of Health and the Netherlands Organization for Scientific Research.