Towards Fluorescence-Guided Head and Neck Cancer Surgery

__Abstract__ Fluorescence-guided cancer surgery provides real-time intraoperative optical feedback on tumor margins and could therefore revolutionize surgical outcomes and patient survival. This thesis focuses on current modalities and cancer targeting strategies of fluorescence-guided head and neck cancer surgery. It was demonstrated in preclinical studies that head and neck tumors could be detected by targeting various hallmarks of cancer. The fundamental limitations of the technique are explained and future perspectives on its use are provided. When practical and technical surgical issues are considered with care, fluorescence imaging can be a very powerful intraoperative tool in guiding the future head and neck surgeon towards radical resection and optimal clinical results

Optical Imaging of Tumor Response to Hyperbaric Oxygen Treatment and Irradiation in an Orthotopic Mouse Model of Head and Neck Squamous Cell Carcinoma

Purpose: Hyperbaric oxygen therapy (HBOT) is used in the treatment of radiation-induced tissue injury but its effect on (residual) tumor tissue is indistinct and therefore investigated in this study. Procedures: Orthotopic FaDu tumors were established in mice, and the response of the (irradiated) tumors to HBOT was monitored by bioluminescence imaging. Near infrared fluorescence imaging using AngioSense750 and Hypoxisense680 was applied to detect tumor vascular permeability and hypoxia. Results: HBOT treatment resulted in accelerated growth of non-irradiated tumors, but mouse survival was improved. Tumor vascular leakiness and hypoxia were enhanced after HBOT, whereas histological characteristics, epithelial-to-mesenchymal transition markers, and metastatic incidence were not influenced. Conclusions: Squamous cell carcinoma responds to HBOT with respect to tumor growth, vascular permeability, and hypoxia, which may have implications for its use in cancer patients. The ability to longitudinally analyze tumor characteristics highlights the versatility and potential of optical imaging methods in oncological research

Raman spectroscopy to discriminate laryngeal squamous cell carcinoma from non-cancerous surrounding tissue

As for many solid cancers, laryngeal cancer is treated surgically, and adequate resection margins are critical for survival. Raman spectroscopy has the capacity to accurately differentiate between cancer and non-cancerous tissue based on their molecular composition, which has been proven in previous work. The aim of this study is to investigate whether Raman spectroscopy can be used to discriminate laryngeal cancer from surrounding non-cancerous tissue. Patients surgically treated for laryngeal cancer were included. Raman mapping experiments were performed ex vivo on resection specimens and correlated to histopathology. Water concentration analysis and CH-stretching region analysis were performed in the high wavenumber range of 2500–4000 cm−1. Thirty-four mapping experiments on 22 resection specimens were used for analysis. Both laryngeal cancer and all non-cancerous tissue structures showed high water concentrations of around 75%. Discriminative information was only found to be present in the CH-stretching region of the Raman spectra of the larynx (discriminative power of 0.87). High wavenumber region Raman spectroscopy can discriminate laryngeal cancer from non-cancerous tissue structures. Contrary to the findings for oral cavity cancer, water concentration is not a discriminating factor for laryngeal cancer.</p

Detecting head and neck lymph node metastases with white light reflectance spectroscopy; a pilot study

Introduction: A challenge in the treatment of patients with head and neck cancer is the management of occult cervical lymph node (LN) metastases. Single-fiber reflectance (SFR) spectroscopy has the potential to detect physiological tissue changes that occur in a positive LN. This pilot study aimed to investigate whether SFR spectroscopy could serve as an alternative or additional technique to detect cervical lymph node metastases. Materials and Methods: We performed intraoperative SFR spectroscopy measurements of LNs with and without malignancies. We analyzed if physiological and scattering parameters were significantly altered in positive LNs. Results: Nine patients with a total of nineteen LNs were included. Three parameters, blood volume fraction (BVF), microvascular saturation (StO2), and Rayleigh amplitude, were significantly lower in positive LNs. They were combined into one optical parameter ‘delta’, using discriminant analysis. Delta was significantly decreased in positive LNs, p = 0,0006. It had a high diagnostic accuracy where the sensitivity, specificity, PPV, and NPV were 90,0%, 88.9%, 90,0%, and 88.9%, respectively. The area under the ROC curve was 96.7% (95% confidence interval 89.7–100.0%). Conclusion: This proof of principle study is a first step in the development of an SFR spectroscopy technique to detect LN metastases in real time. A next step towards this goal is replicating these results in LNs with smaller metastases and in a larger cohort of patients. This future study will combine SFR spectroscopy with fine-needle aspiration, using the same needle, to perform preoperative in vivo measurements.</p

Intraoperative molecular imaging of colorectal lung metastases with SGM-101:a feasibility study

Purpose: Metastasectomy is a common treatment option for patients with colorectal lung metastases (CLM). Challenges exist with margin assessment and identification of small nodules, especially during minimally invasive surgery. Intraoperative fluorescence imaging has the potential to overcome these challenges. The aim of this study was to assess feasibility of targeting CLM with the carcinoembryonic antigen (CEA) specific fluorescent tracer SGM-101. Methods: This was a prospective, open-label feasibility study. The primary outcome was the number of CLM that showed a true positive fluorescence signal with SGM-101. Fluorescence positive signal was defined as a signal-to-background ratio (SBR) ≥ 1.5. A secondary endpoint was the CEA expression in the colorectal lung metastases, assessed with the immunohistochemistry, and scored by the total immunostaining score. Results: Thirteen patients were included in this study. Positive fluorescence signal with in vivo, back table, and closed-field bread loaf imaging was observed in 31%, 45%, and 94% of the tumors respectively. Median SBRs for the three imaging modalities were 1.00 (IQR: 1.00–1.53), 1.45 (IQR: 1.00–1.89), and 4.81 (IQR: 2.70–7.41). All tumor lesions had a maximum total immunostaining score for CEA expression of 12/12. Conclusion: This study demonstrated the potential of fluorescence imaging of CLM with SGM-101. CEA expression was observed in all tumors, and closed-field imaging showed excellent CEA specific targeting of the tracer to the tumor nodules. The full potential of SGM-101 for in vivo detection of the tracer can be achieved with improved minimal invasive imaging systems and optimal patient selection. Trial registration: The study was registered in ClinicalTrial.gov under identifier NCT04737213 at February 2021.</p

Characterization and Evaluation of the Artemis Camera for Fluorescence-Guided Cancer Surgery

Purpose: Near-infrared (NIR) fluorescence imaging can provide the surgeon with real-time visualization of, e.g., tumor margins and lymph nodes. We describe and evaluate the Artemis, a novel, handheld NIR fluorescence camera.Procedures: We evaluated minimal detectable cell numbers (FaDu-luc2, 7D12-IRDye 800CW), preclinical intraoperative detection of sentinel lymph nodes (SLN) using indocyanine green (ICG), and of orthotopic tongue tumors using 7D12-800CW. Results were compared with the Pearl imager. Clinically, three patients with liver metastases were imaged using ICG.Results: Minimum detectable cell counts for Artemis and Pearl were 2 × 105 and 4 × 104 cells, respectively. In vivo, seven SLNs were detected in four mice with both cameras. Orthotopic OSC-19-luc2-cGFP tongue tumors were clearly identifiable, and a minimum FaDu-luc2 tumor size of 1 mm3 could be identified. Six human malignant lesions were identified during three liver surgery procedures.Conclusions: Based on this study, the Artemis system has demonstrated its utility in fluorescence-guided cancer surgery

Endoscopic screening of the upper gastrointestinal tract for second primary tumors in patients with head and neck cancer in a Western country

Background: Patients with head and neck squamous cell carcinoma (HNSCC) relatively frequent develop second primary tumors (SPTs) in the esophagus. Endoscopic screening could lead to timely detection of SPTs in early stages and therefore improves the survival. Methods: We performed a prospective endoscopic screening study in patients with HNSCC in a Western country. Patients with curably treated HNSCC diagnosed January 2017 to July 2021 were included. Routine imaging for HNSCC consisted of flexible transnasal endoscopy with PET/CT or MRI-scan, depending on primary HNSCC location. Screening was performed synchronously(&lt;6 months) or metachronously (≥6 months) after HNSCC diagnosis. The primary outcome was prevalence of SPTs, defined as presence of esophageal high-grade dysplasia or squamous cell carcinoma. Results: We included 202 patients (81% male, mean age 65 years) and performed 250 screening endoscopies. HNSCC was located in the oropharynx(32%), hypopharynx(26%), larynx(22%), and oral cavity(19%). Endoscopic screening was performed within 6 months(34%), 6 months to 1 year(8%), 1 to 2 years(34%), and 2 to 5 years(24%) after HNSCC diagnosis. We detected 11 SPTs in 10 patients(5.0%, 95%CI: 2.4-8.9%) during synchronous(6/85) and metachronous screening(5/165). Most SPTs were detected in early stages(91%) and treated with curative intent with endoscopic resection(80%). No SPTs in screened patients were detected with routine imaging for HNSCC before endoscopic screening. Conclusion: In 5% of patients with HNSCC, an SPT was detected with endoscopic screening. Endoscopic screening should be considered in a selection of HNSCC patients to detect early-stage SPTs, based on highest SPT-risk and life expectancy depending on HNSCC and comorbidities.</p