Immune Checkpoint Inhibitor Toxicity in Head and Neck Cancer: From Identification to Management

Predictors of Radiation Resistance and Novel Radiation Sensitizers in Head and Neck Cancers: Advancing Radiotherapy Efficacy

Radiation resistance in head and neck squamous cell carcinoma (HNSCC), driven by intrinsic and extrinsic factors, poses a significant challenge in radiation oncology. The key contributors are tumor hypoxia, cancer stem cells, cell cycle checkpoint activation, and DNA repair processes (homologous recombination and non-homologous end-joining). Genetic modifications such as TP53 mutations, KRAS mutations, EGFR overexpression, and abnormalities in DNA repair proteins like BRCA1/2 additionally affect radiation sensitivity. Novel radiosensitizers targeting these pathways demonstrate the potential to overcome resistance. Hypoxia-activated drugs and gold nanoparticles enhance the efficacy of radiotherapy and facilitate targeted distribution. Integrating immunotherapy, especially immune checkpoint inhibitors, with radiation therapy, enhances anti-tumor responses and reduces resistance. Epigenetic alterations, such as DNA methylation and histone acetylation, significantly influence radiation response, with the potential for sensitization through histone deacetylase inhibitors and non-coding RNA regulators. Metabolic changes linked to glucose, lipid, and glutamine metabolism influence radiosensitivity, uncovering new targets for radiosensitization. Human papillomavirus (HPV)-associated malignancies exhibit increased radiosensitivity relative to other tumors due to impaired DNA repair mechanisms and heightened immunogenicity. Furthermore, understanding the interplay between HPV oncoproteins and p53 functionality can enhance treatment strategies for HPV-related cancers. Using DNA damage response inhibitors (PARP, ATM/ATR), cell cycle checkpoint inhibitors (WEE1, CHK1/2), and hypoxia-targeted agents as radiosensitizing strategies exhibit considerable promise. Immunomodulatory approaches, including PD-1 and CTLA-4 inhibitors in conjunction with radiation, enhance anti-tumor immunity. Future directions emphasize personalized radiation therapy using genetics, sophisticated medication delivery systems, adaptive radiotherapy, and real-time monitoring. These integrated strategies seek to diminish radiation resistance and improve therapeutic efficacy in HNSCC.

Association of prognostic nutritional index with long-term survival in lung cancer receiving immune checkpoint inhibitors: A meta-analysis

BACKGROUND

This meta-analysis aimed to identify the association of prognostic nutritional index (PNI) with long-term survival in lung cancer patients who received the immune checkpoint inhibitors.

METHODS

The Medline, CNKI, EMBASE, and Web of Science databases were searched up to August 20, 2023. Progression-free survival (PFS) and overall survival (OS) were main outcomes and hazard ratios (HRs) and 95% confidence intervals were combined. Subgroup analysis stratified by the pathological type [non-small cell lung cancer (NSCLC) vs small cell lung cancer (SCLC)], previous treatment history and combination of other treatment was performed.

RESULTS

Twenty-two available studies with 2550 patients were included. Pooled results demonstrated that lower PNI was related to worse PFS (HR = 0.51, P<.001) and OS (HR = 0.43, P<.001). Furthermore, subgroup analysis based on the pathological type (non-small cell lung cancer: HR = 0.52, P<.001 for PFS, HR = 0.41, P<.001 for OS; small cell lung cancer: HR = 0.41, P = .007 for PFS, HR = 0.44, P = .007 for OS), previous treatment history (first-line treatment: HR = 0.67, P<.001 for PFS, HR = 0.52, P<.001 for OS) and combination of other treatment (No: HR = 0.54, P<.001 for PFS, HR = 0.43, P<.001 for OS; Yes: HR = 0.63, P<.001 for PFS, HR = 0.51, P<.001) showed similar findings.

CONCLUSION

PNI is significantly associated with long-term survival in immune checkpoint inhibitors treated lung cancer and patients with lower PNI are more likely to experience poorer prognosis.

Identification of potential biomarkers from amino acid transporter in the activation of hepatic stellate cells via bioinformatics

Background

The etiopathogenesis of hepatic stellate cells (HSC) activation has yet to be completely comprehended, and there has been broad concern about the interplay between amino acid transporter and cell proliferation. This study proposed exploring the molecular mechanism from amino acid transport-related genes in HSC activation by bioinformatic methods, seeking to identify the potentially crucial biomarkers.

Methods

GSE68000, the mRNA expression profile dataset of activated HSC, was applied as the training dataset, and GSE67664 as the validation dataset. Differently expressed amino acid transport-related genes (DEAATGs), GO, DO, and KEGG analyses were utilized. We applied the protein-protein interaction analysis and machine learning of LASSO and random forests to identify the target genes. Moreover, single-gene GESA was executed to investigate the potential functions of target genes via the KEGG pathway terms. Then, a ceRNA network and a drug-gene interaction network were constructed. Ultimately, correlation analysis was explored between target genes and collagen alpha I (COL1A), alpha-smooth muscle actin (α-SMA), and immune checkpoints.

Results

We identified 15 DEAATGs, whose enrichment analyses indicated that they were primarily enriched in the transport and metabolic process of amino acids. Moreover, two target genes (SLC7A5 and SLC1A5) were recognized from the PPI network and machine learning, confirmed through the validation dataset. Then single-gene GESA analysis revealed that SLC7A5 and SLC1A5 had a significant positive correlation to ECM-receptor interaction, cell cycle, and TGF-β signaling pathway and negative association with retinol metabolism conversely. Furthermore, the mRNA expression of target genes was closely correlated with the COL1A and α-SMA, as well as immune checkpoints. Additionally, 12 potential therapeutic drugs were in the drug-gene interaction network, and the ceRNA network was constructed and visualized.

Conclusion

SLC7A5 and SLC1A5, with their relevant molecules, could be potentially vital biomarkers for the activation of HSC.

Immunotherapy for Head and Neck Squamous Cell Carcinoma: Present and Future Approaches and Challenges

Despite significant progress and improving outcomes in the management of head and neck squamous cell carcinoma (HNSCC), there are few effective treatment options for patients with recurrent or metastatic head and neck squamous cell carcinoma. The advent of immune checkpoint inhibitors has changed the treatment algorithm of head and neck squamous cell carcinoma and are approved in the frontline setting for recurrent and metastatic (R/M) head and neck squamous cell carcinomas. Although promising for some patients, most patients with R/M HNSCC do not derive clinical benefit from currently approved checkpoint inhibitors. Many studies are underway to identify the patient population that would benefit the most from immunotherapy as well as postimmunotherapy treatment failures, including novel combinations of immunomodulatory therapies. In this review, we summarize the clinical development of all major clinical trials of immunotherapy in HNSCC.

Multicenter validation of an RNA-based assay to predict anti-PD-1 disease control in patients with recurrent or metastatic head and neck squamous cell carcinoma: the PREDAPT study

BACKGROUND

Despite advances in cancer care and detection, >65% of patients with squamous cell cancer of the head and neck (HNSCC) will develop recurrent and/or metastatic disease. The prognosis for these patients is poor with a 5-year overall survival of 39%. Recent treatment advances in immunotherapy, including immune checkpoint inhibitors like pembrolizumab and nivolumab, have resulted in clinical benefit in a subset of patients. There is a critical clinical need to identify patients who benefit from these antiprogrammed cell death protein 1 (anti-PD-1) immune checkpoint inhibitors.

METHODS

Here, we report findings from a multicenter observational study, PREDicting immunotherapy efficacy from Analysis of Pre-treatment Tumor biopsies (PREDAPT), conducted across 17 US healthcare systems. PREDAPT aimed to validate OncoPrism-HNSCC, a clinical biomarker assay predictive of disease control in patients with recurrent or metastatic HNSCC treated with anti-PD-1 immune checkpoint inhibitors as a single agent (monotherapy) and in combination with chemotherapy (chemo-immunotherapy). The test used RNA-sequencing data and machine learning models to score each patient and place them into groups of low, medium, or high.

RESULTS

The OncoPrism-HNSCC prediction significantly correlated with disease control in both the monotherapy cohort (n=62, p=0.004) and the chemo-immunotherapy cohort (n=50, p=0.01). OncoPrism-HNSCC also significantly predicted progression-free survival in both cohorts (p=0.015 and p=0.037, respectively). OncoPrism-HNSCC had more than threefold higher specificity than programmed death-ligand 1 combined positive score and nearly fourfold higher sensitivity than tumor mutational burden for predicting disease control.

CONCLUSIONS

Here, we demonstrate the clinical validity of the OncoPrism-HNSCC assay in identifying patients with disease control in response to anti-PD-1 immune checkpoint inhibitors.

TRIAL REGISTRATION NUMBER

NCT04510129.

Dysphagia in Head and Neck Cancer

Dysphagia is a common symptom in patients with head and neck cancer that can significantly impact health outcomes and quality of life. The origin of dysphagia in these patients is often multifactorial, making diagnosis and management especially complex. The evaluating otolaryngologist should be well versed with the patient's neoplasm, comorbidities, and treatment history alongside dysphagia-specific imaging modalities. Management is often dynamic, requiring frequent monitoring, interprofessional collaboration, and a variety of supportive and invasive measures to achieve optimal outcomes.

Immune checkpoint inhibitor use in head and neck squamous cell carcinoma: the current landscape and future perspectives

Immune checkpoint inhibitors are licensed for use in patients with unresectable, recurrent or metastatic head and neck squamous cell carcinoma. Multiple published and ongoing trials are assessing efficacy in the curative management of patients in the concomitant, neoadjuvant and/or adjuvant settings, as well as part of multimodality treatment in patients with metastatic disease. This review evaluates the evidence for use of immune checkpoint inhibitors in all stages of head and neck squamous cell carcinoma and considers future approaches.

Effect of preoperative programmed death-1 or programmed death ligand-1 immune check point inhibition on complications after surgery for primary head and neck cancer

BACKGROUND

There is sparse literature on the effect of preoperative immunotherapy on complications after surgery for primary head and neck squamous cell carcinoma (HNSCC). The objectives are to compare complication rates in patients receiving surgery with and without neoadjuvant immune checkpoint inhibitors (nICI) for primary HNSCC and to evaluate factors associated with increased odds of surgical complications.

METHODS

A retrospective review of patients who underwent ablation and free flap reconstruction or transoral robotic surgery (TORS) for primary HNSCC between 2017-2021 was conducted. Complications were compared between patients who underwent surgery with or without nICI before and after propensity score matching. Regression analysis to estimate odds ratios was performed.

RESULTS

A total of 463 patients met inclusion criteria. Free flap reconstruction constituted 28.9% of patients and TORS constituted 71.1% of patients. nICI was administered in 83 of 463 (17.9%) patients. There was no statistically significant difference in surgical, medical, or overall complications between patients receiving surgery with or without nICI. In the unmatched cohort, multivariable model identified non-White race, former/current smoking history, free flap surgery, and perineural invasion as factors significantly associated with increased complications. In the matched cohort, multivariable model identified advanced age and free flap surgery as factors significantly associated with increased complications.

PLAIN LANGUAGE SUMMARY

It is safe to give immunotherapy before major surgery in patients who have head and neck cancer. Advanced age, non-White race, current/former smoking, free flap surgery, and perineural invasion may be associated with increased the odds of surgical complications.

Human Papilloma Virus Positive Oropharyngeal Squamous Cell Carcinoma and the Immune System: Pathogenesis, Immunotherapy and Future Perspectives

Oropharyngeal squamous cell carcinoma (OPSCC), a subset of head and neck squamous cell carcinoma (HNSCC), involves the palatine tonsils, soft palate, base of tongue, and uvula, with the ability to spread to adjacent subsites. Personalized treatment strategies for Human Papillomavirus-associated squamous cell carcinoma of the oropharynx (HPV+OPSCC) are yet to be established. In this article, we summarise our current understanding of the pathogenesis of HPV+OPSCC, the intrinsic role of the immune system, current ICI clinical trials, and the potential role of small molecule immunotherapy in HPV+OPSCC.

Y-Chromosome-Linked Genes Are Associated With Sex-Related Head-Neck Squamous Cell Carcinoma Survival

OBJECTIVE

To define novel gene biomarkers for prognosis of head and neck squamous cell carcinoma (HNSCC) patients' survival.

STUDY DESIGN

Retrospective study.

SETTING

The Cancer Genome Atlas (TCGA) HNSCC RNA-Seq dataset.

METHODS

Coexpressed gene clusters were extracted from TCGA RNA-seq data using our previously published method (EPIG). Kaplan-Meier estimator was then used for overall survival-relevant analysis, with patients partitioned into 3 groups based on gene expression levels: female, male_low, and male_high.

RESULTS

Male had better overall survival than female and male with higher expression level of Y-chromosome-linked (Y-linked) genes had significantly better survival than those with lower expression levels. In addition, male with a higher expression level of Y-linked genes showed even better survival when they have a higher level of coexpressed cluster of genes related to B or T cell immune response. Other clinical conditions related to immune responses also consistently showed favorable effects on the Y-linked genes for survival estimation. Male patients with higher expression level of Y-linked genes also have significantly higher tumor/normal tissue (T/N) ratio of those genes and higher level of several immune responses related clinical measurements (eg, lymphocyte and TCR related). Male patients with lower expression level of Y-linked genes benefited from radiation-only treatment.

CONCLUSIONS

The favorable role of a cluster of coexpressed Y-linked genes in HNSCC patients' survival is potentially associated with elevated level of immune responses. These Y-linked genes could serve as useful prognostic biomarkers for HNSCC patients' survival estimation and treatment.

A new marker constructed from immune-related lncRNA pairs can be used to predict clinical treatment effects and prognosis: in-depth exploration of underlying mechanisms in HNSCC

BACKGROUND

Long non-coding RNA (lncRNA) plays a vital role in tumor proliferation, migration, and treatment. Since it is challenging to standardize the gene expression levels detected by different platforms, the signatures composed of many immune-related single lncRNAs are still inaccurate. Utilizing a gene pair formed of two immune-related lncRNAs and strategically assigning values can effectively meet the demand for a higher-accuracy dual biomarker combination.

METHODS

Co-expression and differential expression analyses were performed on immune genes and lncRNAs data from The Cancer Genome Atlas and the ImmPort database to obtain differentially expressed immune-related lncRNAs for pairwise pairing. The prognostic-related differentially expressed immune-related lncRNAs (PR-DE-irlncRNAs) pairs were then identified by univariate Cox regression and used for lasso regression to construct a prognostic model. Various methods were used to validate the predictive prognostic performance of the model. Additionally, we explored the potential guiding value of the model in immunotherapy and chemotherapy and constructed a nomogram suitable for efficient prognosis prediction. Mechanistic exploration of anti-tumor immunity and mutational perspectives are also included. We also analyzed the correlation between the model and immune checkpoint inhibitors (ICIs)-related, N6-methyadenosine (m6A)-related, and multidrug resistance genes.

RESULTS

We used a total of 20 pairs of PR-DE-irlncRNAs to create a prognosis model. Quantitative real-time polymerase chain reaction experiments further verified the abnormal expression of 11 lncRNAs in HNSCC cells. Various methods have confirmed the excellent performance of the model in predicting patient prognosis. We reasoned that lncRNAs/TP53 mutation might play a positive/negative anti-tumor role through the immune system by multi-perspective analyses. Finally, it was found that the prognostic model was closely related to immunotherapy and chemotherapy as well as the expression of ICIs/m6A/multidrug resistance-related genes.

CONCLUSION

The prognostic model performs excellently in predicting the prognosis of patients and provides the potential value of practical guidance for treatment.

Immunology of Oral Squamous Cell Carcinoma-A Comprehensive Insight with Recent Concepts

This review aims to understand the concept of oral cancer immunology through the notion of immune profiling, immunoediting and immunotherapy, and to gain knowledge regarding its application for the management of oral cancer patients. Oral cancer is an immunogenic tumor where the cells of the tumor microenvironment play an important role in tumorigenesis. Understanding the mechanism of these modulations can help design immunotherapeutic strategies in oral cancer patients. This article gives an overview of immunomodulation in the oral cancer tumor microenvironment, with concepts of immune profiling, immunoediting and immunotherapy. English literature searches via Google Scholar, Web of Science, EBSCO, Scopus, and PubMed database were performed with the key words immunology, tumor microenvironment, cells, cross talk, immune profiling, biomarkers, inflammation, gene expression, techniques, immunoediting, immunosurveillance, tumor escape, immunotherapy, immune checkpoint inhibitors, vaccines in cancer, oral cancer, and head and neck cancer. Original research articles, reviews, and case reports published from 2016-2021 (n = 81) were included to appraise different topics, and were discussed under the following subsections. Literature published on oral cancer immunology reveals that oral cancer immune profiling with appropriate markers and techniques and knowledge on immunoediting concepts can help design and play an effective role in immunotherapeutic management of oral cancer patients. An evaluation of oral cancer immunology helps to determine its role in tumorigenesis, and immunotherapy could be the emerging drift in the effective management of oral cancer.

The role of T-cells in head and neck squamous cell carcinoma: From immunity to immunotherapy

Head and neck squamous cell carcinoma (HNSCC) encompass a group of complex entities of tumours affecting the aerodigestive upper tract. The main risk factors are strongly related to tobacco and alcohol consumption, but also HPV infection is often associated. Surgery, radiotherapy and/or chemotherapy are the standard treatments, though the 5-year overall survival is less than 50%. The advances in genomics, molecular medicine, immunology, and nanotechnology have shed a light on tumour biology which helps clinical researchers to obtain more efficacious and less toxic therapies. Head and neck tumours possess different immune escape mechanisms including diminishing the immune response through modulating immune checkpoints, in addition to the recruitment and differentiation of suppressive immune cells. The insights into the HNSCC biology and its strong interaction with the tumour microenvironment highlights the role of immunomodulating agents. Recently, the knowledge of the immunological features of these tumours has paved the way for the discovery of effective biomarkers that allow a better selection of patients with odds of improving overall survival through immunotherapy. Specially biomarkers regarding immune checkpoint inhibitors antibodies, such as anti-PD-1/PD-L1 and anti-CTLA-4 in combination with standard therapy or as monotherapy. New immunotherapies to treat head and neck cancer carcinomas, such as CAR T cells and nanoparticles have been the center of attention and in this review, we discuss the necessity of finding targets for the T cell in the cancer cells to generate CAR T cells, but also the relevance of evaluating specificity and safety of those therapies.

circ_0000045 promotes proliferation, migration, and invasion of head and neck squamous cell carcinomas via regulating HSP70 and MAPK pathway

Objective

Head and neck squamous cell carcinoma (HNSCC) is one severe malignancy driven by complex cellular and signaling mechanisms. However, the roles of circular RNAs (circRNAs) in HNSCC’s development remains poorly understood. Therefore, this study investigated the functions of differentially expressed circRNAs in regulating HNSCC cell functions.

Methods

Differentially expressed circRNAs were characterized through RNA sequencing in HNSCC tissues. CircRNA’s identity was then confirmed using RT-PCR and Sanger’s sequencing. Next, expression levels of circRNA and mRNA were detected by qRT-PCR, after which protein abundances were measured by Western blotting. Subsequently, the proliferation, migration, and invasion of HNSCC cells was assessed by MTS, wound healing, and Transwell system, respectively, followed by identification of circRNA-binding proteins in HNSCC cells by circRNA pull-down, coupled with mass spectrometry.

Results

Great alterations in circRNA profiles were detected in HNSCC tissues, including the elevated expression of circ_0000045. As observed, silencing of circ_0000045 effectively repressed the proliferation, migration, and invasion of HNSCC cell lines (FaDu and SCC-9). Contrarily, circ_0000045’s overexpression promoted the proliferation, migration, and invasion in FaDu and SCC-9 cells. Results also showed that circ_0000045 was associated with multiple RNA-binding proteins in HNSCC cells, such as HSP70. Moreover, circ_0000045 knockdown enhanced HSP70 expression and inhibited JNK2 and P38’s expression in HNSCC cells, which were oppositely regulated by circ_0000045’s overexpression.

Conclusion

The high expression of circ_0000045; therefore, promoted cell proliferation, migration, and invasion during HNSCC’s development through regulating HSP70 protein and mitogen-activated protein kinase signaling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09880-y.

Imaging of Complications of Chemoradiation

Chemoradiation for head and neck cancer is associated with a variety of early and late complications. Toxicities may affect the aero-digestive tract (mucositis, salivary gland injury), regional osseous and cartilaginous structures (osteoradionecrosis (ORN) and chondronecrosis), vasculature (progressive radiation vasculopathy and carotid blow out syndromes), and neural structures (optic neuritis, myelitis, and brain injury). These may be difficult to distinguish from tumor recurrence on imaging, and may necessitate the use of advanced MRI and molecular imaging techniques to reach the correct diagnosis. Secondary radiation-induced malignancies include thyroid cancer and a variety of sarcomas that may manifest several years after treatment. Checkpoint inhibitors can cause a variety of adverse immune events, including autoimmune hypophysitis and encephalitis.

A Ferroptosis-Related Prognostic Signature Based on Antitumor Immunity and Tumor Protein p53 Mutation Exploration for Guiding Treatment in Patients With Head and Neck Squamous Cell Carcinoma

Background: Due to the lack of accurate guidance of biomarkers, the treatment of head and neck squamous cell carcinoma (HNSCC) has not been ideal. Ferroptosis plays an important role in tumor suppression and treatment of patients. However, tumor protein p53 (TP53) mutation may promote tumor progression through ferroptosis. Therefore, it is particularly important to mine prognostic-related differentially expressed ferroptosis-related genes (PR-DE-FRGs) in HNSCC to construct a prognostic model for accurately guiding clinical treatment. Methods: First, the HNSCC data obtained from The Cancer Genome Atlas (TCGA) was used to identify PR-DE-FRGs for screening candidate genes to construct a prognostic model. We not only used a variety of methods to verify the accuracy of the model for predicting prognosis but also explored the role of ferroptosis in the development of HNSCC from the perspective of the immune microenvironment and mutation. Finally, we explored the correlation between the prognostic model and clinical treatment and drew a high-precision nomogram to predict the prognosis. Results: Seventeen of the 29 PR-DE-FRGs were selected to construct a prognostic model with good predictive performance. Patients in the low-risk group were found to have a greater number of CD8 + T cells, follicular helper T cells, regulatory T cells, mast cells, T-cell costimulations, and type II interferon responses. A higher tumor mutation burden (TMB) was observed in the low-risk group and was associated with a better prognosis. A higher risk score was found in the TP53 mutation group and was associated with a worse prognosis. The risk score is closely related to the expression of immune checkpoint inhibitors (ICIs)-related genes such as PD-L1 and the IC50 of six chemotherapeutic drugs. The nomogram we constructed performs well in predicting prognosis. Conclusion: Ferroptosis may participate in the progression of HNSCC through the immune microenvironment and TP53 mutation. The model we built can be used as an effective predictor of immunotherapy and chemotherapy effects and prognosis of HNSCC patients.

Oral Complications of Head and Neck Cancer Therapy

Current therapies for Head and Neck cancer treatment are extremely advanced. Though, they cause oral complications which have deleterious effects on basic life functions, affect oral and overall health, may lead to significant morbidity and treatment discontinuation and have an impact on survivorship and quality of life. As new therapies are introduced, a new spectrum of oral complications is rising, compromising the mucosal integrity and the salivary function, that may not be recognized, reported and treated properly. Oral complications, often permanent and extremely painful, may include mucositis, xerostomia, dysgeusia, infections, trismus and fibrosis, risk of dental disease and necrosis of the jaw, neurosensory disorders and when targeted therapies and immunotherapy are involved, aphthoid and lichenoid lesions can also be reported. Increased awareness is required for the prevention and management of these complications, which can be best provided by a multidisciplinary team.

Hypothyroidism in Head and Neck Squamous Cell Carcinoma Patients Receiving Radiotherapy With or Without Immune Checkpoint Inhibitors

OBJECTIVES/HYPOTHESIS

Hypothyroidism is a relatively common complication of head and neck squamous cell carcinoma (HNSCC) treatment. The objective of this study was to determine whether the addition of programmed death ligand-1 (PD-1) or programmed death ligand-1 (PD-L1) inhibition (anti-PD-1/PD-L1 therapy) to standard treatment increases the risk of hypothyroidism in HNSCC.

STUDY DESIGN

Retrospective Cohort.

METHODS

This is a retrospective, single institutional cohort study. Patients who received radiotherapy (RT) for HNSCC were identified in the electronic medical record. Patient factors collected include age, sex, body mass index (BMI), smoking status, alcohol use, Charlson comorbidity index, and HNSCC treatment records. The rate of hypothyroidism for patients with HNSCC receiving RT (+/- chemotherapy and surgery) (RT group, n = 101) was compared to that of HNSCC patients receiving RT (+/- chemotherapy and surgery) + anti-PD-1/PD-L1 therapy, either concurrently or after RT (RT + anti-PD-1/PD-L1 group, n = 38).

RESULTS

There was no significant difference in the rate of clinical or subclinical hypothyroidism between the two groups. Multinomial logistic regression found no significant difference in hypothyroidism based on age, sex, or BMI.

CONCLUSIONS

The addition of anti-PD-1/PD-L1 therapy to standard HNSCC treatment does not significantly increase the risk of developing hypothyroidism.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E2413-E2419, 2021.

Biomaterial-Facilitated Immunotherapy for Established Oral Cancers

We evaluated a peptide-based immunotherapy termed SynerGel: an injectable, biomaterial-based platform for intratumoral drug delivery. A drug-mimicking peptide hydrogel named L-NIL-MDP was loaded with an antitumor cyclic dinucleotide (CDN) immunotherapy agonist. The biomaterial combines inducible nitric oxide synthase (iNOS) inhibition with controlled delivery of CDNs, demonstrating between 4- and 20-fold slower drug release than commercially available hydrogels. SynerGel allowed for immune-mediated elimination of established treatment-resistant oral tumors in a murine model, with a median survival of 67.5 days compared with 44 days in no-treatment control. This report details findings for a promising therapy showing improved efficacy over previous hydrogel systems.

Tumor microenvironment and immune-related therapies of head and neck squamous cell carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are a type of common malignant tumor, mainly manifesting as oropharyngeal, oral cavity, laryngopharyngeal, hypopharyngeal, and laryngeal cancers. These highly aggressive malignant tumors reportedly affect more than 830,000 patients worldwide every year. Currently, the main treatments for HNSCC include surgery, radiotherapy, chemotherapy, and immunotherapy, as well as combination therapy. However, the overall 5-year survival rate of HNSCC has remained 50%, and it has not significantly improved in the past 10 years. Previous studies have shown that the tumor microenvironment (TME) plays a crucial role in the recurrence, metastasis, and drug resistance of patients with HNSCC. In this review, we summarize the role of anti-tumor and pro-tumor immune cells, as well as extracellular components in the TME of HNSCC. We also discuss classical HNSCC immunotherapy and highlight examples of clinical trials using CTLA-4 inhibitors and programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1)-related combination therapies. We also outline some molecules in the TME known to regulate immunosuppressive cells. Furthermore, the role and underlying mechanism of radiation therapy on the TME, immune cells, and immune response are discussed.

Head and neck squamous cell carcinoma

Most head and neck cancers are derived from the mucosal epithelium in the oral cavity, pharynx and larynx and are known collectively as head and neck squamous cell carcinoma (HNSCC). Oral cavity and larynx cancers are generally associated with tobacco consumption, alcohol abuse or both, whereas pharynx cancers are increasingly attributed to infection with human papillomavirus (HPV), primarily HPV-16. Thus, HNSCC can be separated into HPV-negative and HPV-positive HNSCC. Despite evidence of histological progression from cellular atypia through various degrees of dysplasia, ultimately leading to invasive HNSCC, most patients are diagnosed with late-stage HNSCC without a clinically evident antecedent pre-malignant lesion. Traditional staging of HNSCC using the tumour-node-metastasis system has been supplemented by the 2017 AJCC/UICC staging system, which incorporates additional information relevant to HPV-positive disease. Treatment is generally multimodal, consisting of surgery followed by chemoradiotherapy (CRT) for oral cavity cancers and primary CRT for pharynx and larynx cancers. The EGFR monoclonal antibody cetuximab is generally used in combination with radiation in HPV-negative HNSCC where comorbidities prevent the use of cytotoxic chemotherapy. The FDA approved the immune checkpoint inhibitors pembrolizumab and nivolumab for treatment of recurrent or metastatic HNSCC and pembrolizumab as primary treatment for unresectable disease. Elucidation of the molecular genetic landscape of HNSCC over the past decade has revealed new opportunities for therapeutic intervention. Ongoing efforts aim to integrate our understanding of HNSCC biology and immunobiology to identify predictive biomarkers that will enable delivery of the most effective, least-toxic therapies.

Challenges in Combining Immunotherapy with Radiotherapy in Recurrent/Metastatic Head and Neck Cancer

Immunotherapy with immune checkpoint inhibitors (ICI) has recently become a standard part of the treatment of recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC), although the response rates are low. Numerous preclinical and clinical studies have now illuminated several mechanisms by which radiotherapy (RT) enhances the effect of ICI. From RT-induced immunogenic cancer cell death to its effect on the tumor microenvironment and vasculature, the involved mechanisms are diverse and intertwined. Moreover, the research of these interactions is challenging because of the thin line between immunostimulatory and the immunosuppressive effect of RT. In the era of active research of immunoradiotherapy combinations, the significance of treatment and host-related factors that were previously seen as being less important is being revealed. The impact of dose and fractionation of RT is now well established, whereas selection of the number and location of the lesions to be irradiated in a multi-metastatic setting is something that is only now beginning to be understood. In addition to spatial factors, the timing of irradiation is as equally important and is heavily dependent on the type of ICI used. Interestingly, using smaller-than-conventional RT fields or even partial tumor volume RT could be beneficial in this setting. Among host-related factors, the role of the microbiome on immunotherapy efficacy must not be overlooked nor can we neglect the role of gut irradiation in a combined RT and ICI setting. In this review we elaborate on synergistic mechanisms of immunoradiotherapy combinations, in addition to important factors to consider in future immunoradiotherapy trial designs in R/M HNSCC.

Combining radiotherapy and immunotherapy in definitive treatment of head and neck squamous cell carcinoma: review of current clinical trials

Background Head and neck squamous cell carcinoma (HNSCC) presents as locally advanced disease in a majority of patients and is prone to relapse despite aggressive treatment. Since immune checkpoint inhibitors (ICI) have shown clinically significant efficacy in patients with recurrent/metastatic HNSCC (R/M HNSCC), a plethora of trials are investigating their role in earlier stages of disease. At the same time, preclinical data showed the synergistic role of concurrently administered radiotherapy and ICIs (immunoradiotherapy) and explained several mechanisms behind it. Therefore, this approach is prospectively tested in a neoadjuvant, definitive, or adjuvant setting in non-R/M HNSCC patients. Due to the intricate relationship between host, immunotherapy, chemotherapy, and radiotherapy, each of these approaches has its advantages and disadvantages. In this narrative review we present the biological background of immunoradiotherapy, as well as a rationale for, and possible flaws of, each treatment approach, and provide readers with a critical summary of completed and ongoing trials. Conclusions While immunotherapy with ICIs has already become a standard part of treatment in patients with R/M HNSCC, its efficacy in a non-R/M HNSCC setting is still the subject of extensive clinical testing. Irradiation can overcome some of the cancer's immune evasive manoeuvres and can lead to a synergistic effect with ICIs, with possible additional benefits of concurrent platinum-based chemotherapy. However, the efficacy of this combination is not robust and details in trial design and treatment delivery seem to be of unprecedented importance.

Nivolumab-related tracheobronchial chondritis: Extremely rare manifestation of an immune-related adverse effect

BACKGROUND

Programmed death-1 checkpoint inhibitors, such as nivolumab, have successfully been utilized for recurrent or metastatic squamous cell carcinoma of the head and neck; however, their use may be associated with immune-related adverse effects (irAEs).

METHODS

We describe a case of tracheobronchial chondritis as a rare irAE in a 72-year-old man with multiple pulmonary metastases of hypopharyngeal squamous cell carcinoma treated with nivolumab, who was seen with a 2-week history of fever, nonproductive cough, and dyspnea.

RESULTS

CT revealed a thickened tracheobronchial wall and narrowed intraluminal space resulting in respiratory symptoms, despite significant clinical response of the metastases. He was clinically diagnosed with tracheobronchial chondritis and treated successfully by steroid therapy. His diagnosis was confirmed by a positive serum anti-collagen type 2 antibody test.

CONCLUSIONS

In addition to interstitial lung disease, tracheobronchial chondritis should be considered as a possible irAE in patients with acute respiratory symptoms after nivolumab administration.