Radiotherapy Controversies and Prospective in Head and Neck Cancer: A Literature-Based Critical Review

Assessment of multispecies biofilm growth on root canal dentin under different radiation therapy regimens

OBJECTIVES

To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens.

MATERIALS AND METHODS

Sixty-three human root dentin cylinders were distributed into six groups. In three groups, no biofilm was formed (n = 3): NoRT) non-irradiated dentin; RT55) 55 Gy; and RT70) 70 Gy. In the other three groups (n = 18), a 21-day multispecies biofilm (Enterococcus faecalis, Streptococcus mutans, and Candida albicans) was formed in the canal: NoRT + Bio) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm. The biofilm was quantified (CFUs/mL). Biofilm microstructure was assessed under SEM. Microbial penetration into dentinal tubules was assessed under CLSM. For the biofilm biomass and dentin microhardness pre- and after biofilm growth assessments, 45 bovine dentin specimens were distributed into three groups (n = 15): NoRT) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm.

RESULTS

Irradiated specimens (70 Gy) had higher quantity of microorganisms than non-irradiated (p = .010). There was gradual increase in biofilm biomass from non-irradiated to 55 Gy and 70 Gy (p < .001). Irradiated specimens had greater reduction in microhardness after biofilm growth. Irradiated dentin led to the growth of a more complex and irregular biofilm. There was microbial penetration into the dentinal tubules, regardless of the radiation regimen.

CONCLUSION

Radiotherapy increased the number of microorganisms and biofilm biomass and reduced dentin microhardness. Microbial penetration into dentinal tubules was noticeable.

CLINICAL RELEVANCE

Cumulative and potentially irreversible side effects of radiotherapy affect biofilm growth on root dentin. These changes could compromise the success of endodontic treatment in oncological patients undergoing head and neck radiotherapy.

Hyperbaric oxygen therapy restores wound healing in irradiated gingiva to a similar level to that in healthy gingiva

OBJECTIVE

This study aimed to investigate the involvement of mitochondrial biogenesis, and determine the extent of fibroblast proliferation and cellular apoptosis, in the gingiva of patients who had undergone head and neck radiation, after receiving hyperbaric oxygen therapy (HBOT), in comparison with normal gingiva.

METHOD

A total of 16 patients who had undergone head and neck radiation with HBOT and six healthy subjects were included in the study. After the completion of radiation therapy, patients received HBOT at 2 ATA for 90 minutes per session, and for 20 sessions per patient. Samples of gingival tissues were then taken. The levels of: transforming growth factor beta (TGF-β); phospho-nuclear factor kappa-light-chain-enhancer of activated B cells (p-NFϰB); nuclear factor kappa-light-chain-enhancer of activated B cells (NFϰB); proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α); phospho-dynamin-related protein 1 at ser616 (p-Drp1ser616); dynamin-related protein 1 (Drp1); Bcl-2-associated X-protein (Bax); and B-cell lymphoma 2 (Bcl-2) were determined using a Western blot. Independent t-test and Chi-squared tests were used in the study.

RESULTS

There were no differences in the levels of TGF-β, p-NFϰB, NFϰB, p-Drp1ser616, Drp1, Bax and Bcl-2 between the two groups. However, the level of PGC-1α was greater in irradiated gingival tissues with HBOT than in the healthy gingiva.

CONCLUSION

Radiation-induced impaired wound healing can be improved by HBOT as indicated by levels of apoptosis, mitochondrial dynamics, cell proliferation and inflammation in irradiated gingiva with HBOT to a similar level to normal healthy gingiva. These findings may occur through an increase in mitochondrial biogenesis following HBOT.

Trehalose versus carboxymethylcellulose oral spray for relieving radiation-induced xerostomia in head and neck cancer patients: a randomized controlled trial

BACKGROUND

The aim of this study was to investigate the effect of trehalose oral spray to relieve radiation-induced xerostomia on a randomized controlled trial (RCT).

METHODS

Prior to RCT, the effect of trehalose (5-20%) on the epithelial growth of fetal mouse salivary gland (SG) explants was evaluated to confirm if 10% trehalose exerted the best epithelial outcomes. Participants who completed radiotherapy for head and neck cancer (HNC) treatment were enrolled in a double-blind RCT, according to inclusion and exclusion criteria as per the CONSORT statement. The experimental group (n = 35) received 10% trehalose spray, while the control group (n = 35) received carboxymethylcellulose (CMC) spray to apply intra-orally 4 times/day for 14 days. Salivary pH and unstimulated salivary flow rate were recorded pre- and post-interventions. The Xerostomia-related Quality of Life scale (XeQoLs) was filled, and scores assessed post-interventions.

RESULTS

In the SG explant model, pro-acinar epithelial growth and mitosis was supported by 10% topical trehalose. As for RCT outcomes, salivary pH and unstimulated salivary flow rate were significantly improved after use of 10% trehalose spray when compared to CMC (p < 0.05). Participants reported an improvement of XeQoLs dimension scores after using trehalose or CMC oral sprays in terms of physical, pain/discomfort, and psychological dimensions (p < 0.05), but not social (p > 0.05). When comparing between CMC and trehalose sprays, XeQoLs total scores were not statistically different (p > 0.05).

CONCLUSIONS

The 10% trehalose spray improved salivary pH, unstimulated salivary flow rate, and the quality-of-life dimensions linked with physical, pain/discomfort, and psychological signs. The clinical efficacy of 10% trehalose spray was equivalent with CMC-based saliva substitutes for relieving radiation-induced xerostomia; therefore, trehalose may be suggested in alternative to CMC-based oral spray.(Thai Clinical Trials Registry; https://www.thaiclinicaltrials.org/ TCTR20190817004).

Expression of OLR1 gene on tumor-associated macrophages of head and neck squamous cell carcinoma, and its correlation with clinical outcome

Head and neck squamous cell carcinoma (HNSCC) is one of the most heavily immune infiltrated human tumors, having distinct immune subtypes associated with different molecular characteristics and clinical outcomes. The tumor microenvironment (TME) of HNSCC which was dominated by tumor-associated macrophages (TAMs) had a relatively inferior prognosis. High levels of oxidized low-density lipoprotein receptor 1 (OLR1) expression are associated with more aggressive and metastatic characteristics in multiple cancers. However, the link between the OLR1 expression and immunosuppression of TME, and the molecular mechanisms which govern intratumoral TAMs behavior are unclear. Here, we performed the transcriptional analysis based on a single-cell RNA-sequencing (scRNA-seq) dataset of HNSCC, and found that the OLR1 expression was specifically enriched on the TAMs. Evaluation of protein expression within histologic sections of primary HNSCC patient samples showed a co-expression pattern of OLR1 and CD68 on macrophages. A total of 498 tumor samples of HNSCC patients from The Cancer Genome Atlas (TCGA) database were also analyzed. Remarkably, OLR1 expression was dramatically higher in HNSCC tissues than that in adjacent normal tissues, and the patients with high levels of OLR1 expression had significantly unfavorable overall survival (Hazard Ratio = 1.724, log-rank P-value = 0.0066) when compared to patients harboring low expression levels of OLR1. In summary, we reported that the specific expression of OLR1 on the TAMs was significantly correlated with poor survival outcomes, revealing that OLR1 could serve as a potential prognosis marker and promising target for immunotherapy in HNSCC.

Longitudinal Molecular Profiling of Circulating Tumor Cells in Metastatic Renal Cell Carcinoma

PURPOSE

Liquid biopsies in metastatic renal cell carcinoma (mRCC) provide a unique approach to understand the molecular basis of treatment response and resistance. This is particularly important in the context of immunotherapies, which target key immune-tumor interactions. Unlike metastatic tissue biopsies, serial real-time profiling of mRCC is feasible with our noninvasive circulating tumor cell (CTC) approach.

METHODS

We collected 457 longitudinal liquid biopsies from 104 patients with mRCC enrolled in one of two studies, either a prospective cohort or a phase II multicenter adaptive immunotherapy trial. Using a novel CTC capture and automated microscopy platform, we profiled CTC enumeration and expression of HLA I and programmed cell death-ligand 1 (PD-L1). Given their diametric immunological roles, we focused on the HLA I to PD-L1 ratio (HP ratio).

RESULTS

Patients with radiographic responses showed significantly lower CTC abundances throughout treatment. Furthermore, patients whose CTC enumeration trajectory was in the highest quartile (> 0.12 CTCs/mL annually) had shorter overall survival (median 17.0 months v 21.1 months, P < .001). Throughout treatment, the HP ratio decreased in patients receiving immunotherapy but not in patients receiving tyrosine kinase inhibitors. Patients with an HP ratio trajectory in the highest quartile (≥ 0.0012 annually) displayed significantly shorter overall survival (median 18.4 months v 21.2 months, P = .003).

CONCLUSION

In the first large longitudinal CTC study in mRCC to date to our knowledge, we identified the prognostic importance of CTC enumeration and the change over time of both CTC enumeration and the HP ratio. These insights into changes in both tumor burden and the molecular profile of tumor cells in response to different treatments provide potential biomarkers to predict and monitor response to immunotherapy in mRCC.

Radioprotective effects and mechanism of HL-003 on radiation-induced salivary gland damage in mice

Ionizing radiation (IR) can cause damage to the structure and function of salivary glands. Our research group independently synthesized the ROS scavenger, HL-003. The aim of this study was to explore the protective effects and underlying mechanisms of HL-003 on radiation-induced salivary gland injury. Salivary flow rate measurement, H&E staining, immunohistochemistry, FRAP, TUNEL, and western blotting were used to evaluate the radioprotective effect on salivary glands. The results showed that HL-003 protected the salivary secretion function by protecting the AQP-5 protein, on the salivary epithelial cell membrane, from IR damage. HL-003 reduced oxidative stress in the salivary gland by regulating the expression of ROS-related proteins NOX4, SOD2, and 8-OHdG. Furthermore, HL-003 downregulated the expression of p-p53, Bax, caspase 3, and caspase 9, and upregulated the expression of Bcl-2, suggesting that it could inhibit the activation of p53 to reduce cell apoptosis. In conclusion, HL-003 is an effective radioprotector that prevents damage of the radiation-induced salivary gland.

Proton Image-guided Radiation Assignment for Therapeutic Escalation via Selection of locally advanced head and neck cancer patients [PIRATES]: A Phase I safety and feasibility trial of MRI-guided adaptive particle radiotherapy

INTRODUCTION

Radiation dose-escalation for head and neck cancer (HNC) patients aiming to improve cure rates is challenging due to the increased risk of unacceptable treatment-induced toxicities. With "Proton Image-guided Radiation Assignment for Therapeutic Escalation via Selection of locally advanced head and neck cancer patients" (PIRATES), we present a novel treatment approach that is designed to facilitate dose-escalation while minimizing the risk of dose-limiting toxicities for locally advanced HPV-negative HNC patients. The aim of this Phase I trial is to assess the safety & feasibility of PIRATES approach.

METHODS

The PIRATES protocol employs a multi-faceted dose-escalation approach to minimize the risk of dose-limiting toxicities (DLTs): 1) sparing surrounding normal tissue from extraneous dose with intensity-modulated proton therapy, 2) mid-treatment hybrid hyper-fractionation for radiobiologic normal tissue sparing; 3) Magnetic Resonance Imaging (MRI) guided mid-treatment boost volume adaptation, and 4) iso-effective restricted organ-at-risk dosing to mucosa and bone tissues.The time-to-event Bayesian optimal interval (TITE-BOIN) design is employed to address the challenge of the long DLT window of 6 months and find the maximum tolerated dose. The primary endpoint is unacceptable radiation-induced toxicities (Grade 4, mucositis, dermatitis, or Grade 3 myelopathy, osteoradionecrosis) occurring within 6 months following radiotherapy. The second endpoint is any grade 3 toxicity occurring in 3-6 months after radiation.

DISCUSSION

The PIRATES dose-escalation approach is designed to provide a safe avenue to intensify local treatment for HNC patients for whom therapy with conventional radiation dose levels is likely to fail. PIRATES aims to minimize the radiation damage to the tissue surrounding the tumor volume with the combination of proton therapy and adaptive radiotherapy and within the high dose tumor volume with hybrid hyper-fractionation and not boosting mucosal and bone tissues. Ultimately, if successful, PIRATES has the potential to safety increase local control rates in HNC patients with high loco-regional failure risk.Trial registration: ClinicalTrials.gov ID: NCT04870840; Registration date: May 4, 2021.Netherlands Trial Register ID: NL9603; Registration date: July 15, 2021.

Biological consequences of cancer radiotherapy in the context of oral squamous cell carcinoma

Approximately 50% of subjects with cancer have been treated with ionizing radiation (IR) either as a curative, adjuvant, neoadjuvant or as a palliative agent, at some point during the clinical course of their disease. IR kills cancer cells directly by injuring their DNA, and indirectly by inducing immunogenic cell killing mediated by cytotoxic T cells; but it can also induce harmful biological responses to non-irradiated neighbouring cells (bystander effect) and to more distant cells (abscopal effect) outside the primary tumour field of irradiation.Although IR can upregulate anti-tumour immune reactions, it can also promote an immunosuppressive tumour microenvironment. Consequently, radiotherapy by itself is seldom sufficient to generate an effective long lasting immune response that is capable to control growth of metastasis, recurrence of primary tumours and development of second primary cancers. Therefore, combining radiotherapy with the use of immunoadjuvants such as immune checkpoint inhibitors, can potentiate IR-mediated anti-tumour immune reactions, bringing about a synergic immunogenic cell killing effect.The purpose of this narrative review is to discuss some aspects of IR-induced biological responses, including factors that contributes to tumour radiosensitivity/radioresistance, immunogenic cell killing, and the abscopal effect.

Dose predictions for [177Lu]Lu-DOTA-panitumumab F(ab')2 in NRG mice with HNSCC patient-derived tumour xenografts based on [64Cu]Cu-DOTA-panitumumab F(ab')2 - implications for a PET theranostic strategy

Background

Epidermal growth factor receptors (EGFR) are overexpressed on many head and neck squamous cell carcinoma (HNSCC). Radioimmunotherapy (RIT) with F(ab')₂ of the anti-EGFR monoclonal antibody panitumumab labeled with the β-particle emitter, ¹⁷⁷Lu may be a promising treatment for HNSCC. Our aim was to assess the feasibility of a theranostic strategy that combines positron emission tomography (PET) with [⁶⁴Cu]Cu-DOTA-panitumumab F(ab')₂ to image HNSCC and predict the radiation equivalent doses to the tumour and normal organs from RIT with [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂.

Results

Panitumumab F(ab')₂ were conjugated to DOTA and complexed to ⁶⁴Cu or ¹⁷⁷Lu in high radiochemical purity (95.6 ± 2.1% and 96.7 ± 3.5%, respectively) and exhibited high affinity EGFR binding (K_d = 2.9 ± 0.7 × 10^− 9 mol/L). Biodistribution (BOD) studies at 6, 24 or 48 h post-injection (p.i.) of [⁶⁴Cu]Cu-DOTA-panitumumab F(ab')₂ (5.5–14.0 MBq; 50 μg) or [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ (6.5 MBq; 50 μg) in NRG mice with s.c. HNSCC patient-derived xenografts (PDX) overall showed no significant differences in tumour uptake but modest differences in normal organ uptake were noted at certain time points. Tumours were imaged by microPET/CT with [⁶⁴Cu]Cu-DOTA-panitumumab F(ab')₂ or microSPECT/CT with [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ but not with irrelevant [¹⁷⁷Lu]Lu-DOTA-trastuzumab F(ab')₂. Tumour uptake at 24 h p.i. of [⁶⁴Cu]Cu-DOTA-panitumumab F(ab')₂ [14.9 ± 1.1% injected dose/gram (%ID/g) and [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ (18.0 ± 0.4%ID/g) were significantly higher (P < 0.05) than [¹⁷⁷Lu]Lu-DOTA-trastuzumab F(ab')₂ (2.6 ± 0.5%ID/g), demonstrating EGFR-mediated tumour uptake. There were no significant differences in the radiation equivalent doses in the tumour and most normal organs estimated for [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ based on the BOD of [⁶⁴Cu]Cu-DOTA-panitumumab F(ab')₂ compared to those estimated directly from the BOD of [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ except for the liver and whole body which were modestly underestimated by [⁶⁴Cu]Cu-DOTA-panitumumab F(ab')₂. Region-of-interest (ROI) analysis of microPET/CT images provided dose estimates for the tumour and liver that were not significantly different for the two radioimmunoconjugates. Human doses from administration of [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ predicted that a 2 cm diameter HNSCC tumour in a patient would receive 1.1–1.5 mSv/MBq and the whole body dose would be 0.15–0.22 mSv/MBq.

Conclusion

A PET theranostic strategy combining [⁶⁴Cu]Cu-DOTA-panitumumab F(ab')₂ to image HNSCC tumours and predict the equivalent radiation doses in the tumour and normal organs from RIT with [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ is feasible. RIT with [¹⁷⁷Lu]Lu-DOTA-panitumumab F(ab')₂ may be a promising approach to treatment of HNSCC due to frequent overexpression of EGFR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41181-021-00140-1.

Oral squamous cell carcinoma (OSCC)-derived exosomal MiR-221 targets and regulates phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) to promote human umbilical vein endothelial cells migration and tube formation

Oral squamous cell carcinoma (OSCC) is the most common tumor of the oral cavity. Studies have shown that exosomal miRNAs from cancer cells play an important role in mediating the cellular environment. The objective was to investigate the effect of OSCC-derived exosomes microRNA-221 (miR-221) in OSCC. We used quantitative real-time PCR (qRT-PCR) and western blotting to determine PIK3R1 and miR-221 expressions in OSCC tissue or peripheral blood serum. Exosomes of OSCC cell line CAL27 were extracted and characterized. Exosomal miR-221 expression was detected by qRT-PCR. Dual-luciferase was performed to validate the targeted regulatory relationship of miR-221 on PIK3R1. Transwell and tube formation assay were applied to detect the effect of OSCC-derived exosomal miR-221 on HUVEC migration and angiogenesis. qRT-PCR confirmed that PIK3R1 expression was downregulated in OSCC tissue and cell line, while miR-221 expression was upregulated. miR-221 expression in OSCC cell line-derived exosome elevated. miR-221 could target and negatively regulate PIK3R1 expression. In addition, OSCC-derived miR-221 could promote HUVEC migration and angiogenesis. In conclusion, OSCC-derived exosomal miR-221 could target and negatively regulate PIK3R1 expression, as well as promote vascular endothelial cell migration and angiogenesis.

Retrospective study of the clinicopathological characteristics and prognosis of elderly patients with oropharyngeal squamous cell carcinoma

Objective

Oropharyngeal squamous cell carcinoma (OPSCC) is a malignant tumor that occurs at the tongue base, soft palate, palatine tonsil, and pharyngeal wall. Few studies of OPSCC have been performed in elderly patients.

Methods

Patients with human papilloma virus (HPV)-related OPSCC were extracted from the Head and Neck with HPV Status Database of the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2016. We identified 355 patients with HPV-positive status, and we retrospectively evaluated elderly (≥65 years) and younger (30–64 years) patient groups to compare the differences.

Results

Of the 355 patients who were diagnosed with HPV-related OPSCC, 113 constituted the elderly group. Comparing the elderly group with the younger group, the 3-year HPV-positive overall survival (OS) rates were 62.4% and 70.2%, respectively, and the 5-year OS rates were 50.4% and 59.2%, respectively. Cox regression analysis demonstrated that tumor (T) stage and chemotherapy were prognostic factors for OS.

Conclusion

Elderly patients with OPSCC had different clinicopathological characteristics. T stage and chemotherapy should be priorities when evaluating the OS of elderly patients with OPSCC.

Targeted Treatment of Head and Neck (Pre)Cancer: Preclinical Target Identification and Development of Novel Therapeutic Applications

Head and neck squamous cell carcinomas (HNSCC) develop in the mucosal lining of the upper-aerodigestive tract. In carcinogen-induced HNSCC, tumors emerge from premalignant mucosal changes characterized by tumor-associated genetic alterations, also coined as 'fields' that are occasionally visible as leukoplakia or erythroplakia lesions but are mostly invisible. Consequently, HNSCC is generally diagnosed de novo at more advanced stages in about 70% of new diagnosis. Despite intense multimodality treatment protocols, the overall 5-years survival rate is 50-60% for patients with advanced stage of disease and seems to have reached a plateau. Of notable concern is the lack of further improvement in prognosis despite advances in treatment. This can be attributed to the late clinical presentation, failure of advanced HNSCC to respond to treatment, the deficit of effective targeted therapies to eradicate tumors and precancerous changes, and the lack of suitable markers for screening and personalized therapy. The molecular landscape of head and neck cancer has been elucidated in great detail, but the absence of oncogenic mutations hampers the identification of druggable targets for therapy to improve outcome of HNSCC. Currently, functional genomic approaches are being explored to identify potential therapeutic targets. Identification and validation of essential genes for both HNSCC and oral premalignancies, accompanied with biomarkers for therapy response, are being investigated. Attentive diagnosis and targeted therapy of the preceding oral premalignant (preHNSCC) changes may prevent the development of tumors. As classic oncogene addiction through activating mutations is not a realistic concept for treatment of HNSCC, synthetic lethality and collateral lethality need to be exploited, next to immune therapies. In recent studies it was shown that cell cycle regulation and DNA damage response pathways become significantly altered in HNSCC causing replication stress, which is an avenue that deserves further exploitation as an HNSCC vulnerability for treatment. The focus of this review is to summarize the current literature on the preclinical identification of potential druggable targets for therapy of (pre)HNSCC, emerging from the variety of gene knockdown and knockout strategies, and the testing of targeted inhibitors. We will conclude with a future perspective on targeted therapy of HNSCC and premalignant changes.

Immune Check-Point Inhibitors and Standard Chemoradiotherapy in Definitive Head and Neck Cancer Treatment

In head and neck cancer management, there is a need for tailored approaches to optimally implement clinical outcomes. Based on the assumption that efficacy and long-term toxicity are not satisfactory for standard concurrent platinum-based chemoradiotherapy, several trials have been designed to test whether induction immunotherapy and/or concomitant immunotherapy and radiotherapy result in improved survival and toxicity outcomes. Here, we present an overview of the most recent concomitant therapeutic strategies for head and neck cancer, focusing on the knowledge available regarding check-point inhibitors. The aim is to present the characteristics of the main check-point inhibitors and to summarize the clinical trials on the combination of immune check-point inhibitors and (chemo)radiotherapy in the definitive HNC setting, in order to provide a useful clinical tool for further research.

Adding value to tumor staging in head and neck cancer: The role of metabolic parameters as prognostic factors

BACKGROUND

Validated biomarkers in head and neck squamous cell carcinoma (HNSCC) are scarce.

METHODS

We retrospectively analyzed 62 patients with HNSCC treated with radiotherapy +/- concurrent chemotherapy. Pretreatment metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were measured in a ¹⁸ F-FDG positron emission tomography using a liver dependent standardized uptake value threshold. Cox regression analyses were performed to find associations with disease-free survival (DFS) and overall survival (OS).

RESULTS

High values of MTV (>37 ml) were independently associated with a worse DFS (hazard ratio [HR] = 3.45; 95% confidence interval [CI], 1.52-7.84) and OS (HR = 3.27; 95% CI, 1.41-7.57). Similar results were found for high values of TLG (>247 g) for DFS (HR = 3.32; 95% CI, 1.44-7.65) and OS (HR = 3.42; 95% CI, 1.45-8.07).

CONCLUSIONS

MTV and TLG can be considered as independent prognostic factors for DFS and OS in patients with HNSCC. Considering how easily obtainable they are, they may be useful for predicting clinical outcomes in these patients.

A Mechanistic Overview of Taste Bud Maintenance and Impairment in Cancer Therapies

Since the early 20th century, progress in cancer therapies has significantly improved disease prognosis. Nonetheless, cancer treatments are often associated with side effects that can negatively affect patient well-being and disrupt the course of treatment. Among the main side effects, taste impairment is associated with depression, malnutrition, and morbid weight loss. Although relatively common, taste disruption associated with cancer therapies remains poorly understood. Here, we review the current knowledge related to the molecular mechanisms underlying taste maintenance and disruption in the context of cancer therapies.

A Bioadhesive Barrier-Forming Oral Liquid Gel Improved Oral Mucositis and Nutritional Status in Patients With Head and Neck Cancers Undergoing Radiotherapy: A Retrospective Single Center Study

Background

Episil^® is a bioadhesive barrier-forming oral liquid gel that can relieve oral mucositis (OM) caused by radiotherapy (RT) and hence relieves pain effectively. In this study, we observed the effects of Episil^® on the OM and nutritional status of patients with head and neck cancers (HNCs) undergoing RT.

Methods

A total of 50 HNC patients were divided into the Episil^® (25 patients) and control (25 patients) groups. Patients in the Episil^® group were sprayed with Episil^®. In the control group, the kangfuxin solution or Kangsu™ oral gargle was used. Medical staff assessed the OM extent and timing as well as the nutritional status during treatment and recorded adverse reactions other than OM. The nutritional status assessment included the following indicators: Patient Generated-Subjective Global Assessment (PG-SGA) score, body mass index (BMI), body weight, albumin levels, and other hematological indicators.

Results

The incidence of high-level OM (III–IV) after RT was lower in the Episil^® group than in the control group (P < 0.05). Nutritional status assessments showed that the Episil^® group had a lower percentage of weight loss than the control group at weeks 4 and 7 after RT. Similar results were also obtained for BMI and albumin levels (P < 0.05). Moreover, according to PG-SGA scores, fewer patients in the Episil^® group were malnourished and more patients were well-nourished (P < 0.05) compared with the control group.

Conclusion

Episil^® effectively improved OM and malnutrition in HNC patients who received RT and has a good clinical application value.

Bardoxolone-Methyl (CDDO-Me) Impairs Tumor Growth and Induces Radiosensitization of Oral Squamous Cell Carcinoma Cells

Radiotherapy represents a common treatment strategy for patients suffering from oral squamous cell carcinoma (OSCC). However, application of radiotherapy is immanently limited by radio-sensitivity of normal tissue surrounding the tumor sites. In this study, we used normal human epithelial keratinocytes (NHEK) and OSCC cells (Cal-27) as models to investigate radio-modulating and anti-tumor effects of the synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9,-dien-28-oic acid methyl ester (CDDO-Me). Nanomolar CDDO-Me significantly reduced OSCC tumor xenograft-growth in-ovo applying the chick chorioallantoic membrane (CAM) assay. In the presence of CDDO-Me reactive oxygen species (ROS) were found to be reduced in NHEK when applying radiation doses of 8 Gy, whereas ROS levels in OSCC cells rose significantly even without radiation. In parallel, CDDO-Me was shown to enhance metabolic activity in malignant cells only as indicated by significant accumulation of reducing equivalents NADPH/NADH. Furthermore, antioxidative heme oxygenase-1 (HO-1) levels were only enhanced in NHEK and not in the OSCC cell line, as shown by immunoblotting. Clonogenic survival was left unchanged by CDDO-Me treatment in NHEK but revealed to be abolished almost completely in OSCC cells. Our results indicate anti-cancer and radio-sensitizing effects of CDDO-Me treatment in OSCC cells, whereas nanomolar CDDO-Me failed to provoke clear detrimental consequences in non-malignant keratinocytes. We conclude, that the observed differential aftermath of CDDO-Me treatment in malignant OSCC and non-malignant skin cells may be utilized to broaden the therapeutic range of clinical radiotherapy.

Regeneration of irradiation-damaged esophagus by local delivery of mesenchymal stem-cell spheroids encapsulated in a hyaluronic-acid-based hydrogel

Radiation therapy (RT) is a typical treatment for head and neck cancers. Generally, prolonged irradiation of the esophagus causes esophageal fibrosis due to increased reactive oxygen species and proinflammatory cytokines. This study was designed to determine whether catechol-functionalized hyaluronic acid (HA-CA) hydrogel-encapsulated human mesenchymal stem-cell spheroids (MSC-SPs) could ameliorate damage to the esophagus in a mouse model of radiation-induced esophageal fibrosis. MSC-SPs were cultured in concave microwells 600 μm in diameter at a cell density of 1 × 10⁶ cells per mL. Most cells formed spheroids with a 100-300 μm size distribution in concave microwells. MSC-SPs were well maintained in the HA gel, and live-dead staining confirmed that most cells survived. The HA gel containing the MSC-SPs was then injected into the damaged esophageal layer. Inflammatory signs or adverse tissue reactions were not observed after esophageal injection of HA-gel-encapsulated MSC-SPs. Based on Masson's trichrome staining at 4 and 12 weeks postinjection, the inner esophageal layer (IEL) was significantly thinner in the MSC-SP + HA gel group compared to those in the other experimental groups. While the saline and HA gel treatments made the esophageal muscles loose and thick, the MSC-SP + HA gel group showed bundles of tightly packed esophageal muscles, as assayed by desmin immunostaining. qPCR analysis showed that epithelial genes tended to increase over time in the MSC-SP + HA gel group, and the expression of most fibrosis-related genes decreased. This study proposes the potential of using HA-CA-hydrogel-encapsulated MSC-SPs as a promising therapy against radiation-induced esophageal fibrosis.

Advanced nanomaterials for hypoxia tumor therapy: challenges and solutions

In recent years, nanomaterials and nanotechnology have emerged as vital factors in the medical field with a unique contribution to cancer medicine. Given the increasing number of cancer patients, it is necessarily required to develop innovative strategies and therapeutic modalities to tackle hypoxia, which forms a hallmark and great barrier in treating solid tumors. The present review details the challenges in nanotechnology-based hypoxia, targeting the strategies and solutions for better therapeutic performances. The interaction between hypoxia and tumor is firstly introduced. Then, we review the recently developed engineered nanomaterials towards multimodal hypoxia tumor therapies, including chemotherapy, radiotherapy, and sonodynamic treatment. In the next part, we summarize the nanotechnology-based strategies for overcoming hypoxia problems. Finally, current challenges and future directions are proposed for successfully overcoming the hypoxia tumor problems.

Is there evidence that radiotherapy for head and neck cancer influences the incidence of dental caries?

Data sources Six databases (MEDLINE, EMBASE, CENTRAL, ProQuest, Scopus and Web of Science) and two trial registries (ICTRP, ClinicalTrials.gov) were searched from their inception to May 2019 using a search strategy developed for OVID (MEDLINE/EMBASE).Study selection This systematic review included observational studies and randomised controlled trials related to the incidence of dental caries in patients with a history of head and neck radiotherapy. In addition, studies in which patients received radiotherapy treatment combined with surgical and/or chemotherapy treatment were also included. Study patients all had their teeth assessed and treated before radiotherapy. The diagnosis of caries may have been clinical and/or radiographic and, patients were followed for at least three months. Only English-language papers were included. Studies involving patients with recurrent cancer or with a repeated course of radiotherapy were excluded.Data extraction and synthesis Studies were selected by two independent reviewers, however, if a consensus could not be reached, a third reviewer was consulted. A total of 847 papers were selected through the search. Only 22 studies met the inclusion criteria. Selected articles included three randomised or quasi-randomised controlled trials and 19 observational studies, of which, seven were retrospective studies. The proportions of patients who developed caries after radiotherapy were pooled using a random-effects model. To inquire the between-study heterogeneity, a chi-square standard test was performed. To determine the degree of heterogeneity in proportions across studies, the I2 statistic was calculated. A funnel plot was built to evaluate the publication bias. To verify the correlation between relevant variables (radiation dose, chemotherapy in addition to radiotherapy, cancer site) and the proportion who developed dental caries, a meta-regression was performed. The STATA version 14 software was used for all statistical analysis.Results In the meta-analysis, the pooled percentage obtained of patients with head and neck cancer who developed dental caries post-radiotherapy, considering 15 included studies, was 29%. However, after excluding six studies on the basis of follow-up greater than two years, the pooled percentage increased to 37%. Furthermore, studies with a higher proportion of patients treated with chemotherapy in addition to radiotherapy (after the exclusion of an outlier), and also studies with a higher mean/median radiotherapy dose exposure, had an increased incidence of dental caries (p = 0.02). However, the results should be considered with caution due to the heterogeneity of the included studies.Conclusions The review showed that there is an incidence of approximately 29% of dental caries in patients with head and neck cancer after radiotherapy and, if considering only patients within 2 years post-radiotherapy, the percentage increases to approximately 37%. However, further studies are needed to allow a better understanding of the various factors related to the development of dental caries in patients with head and neck cancer treated with radiotherapy.

Radiosensitising Cancer Using Phosphatidylinositol-3-Kinase (PI3K), Protein Kinase B (AKT) or Mammalian Target of Rapamycin (mTOR) Inhibitors

Radiotherapy is routinely used as a neoadjuvant, adjuvant or palliative treatment in various cancers. There is significant variation in clinical response to radiotherapy with or without traditional chemotherapy. Patients with a good response to radiotherapy demonstrate better clinical outcomes universally across different cancers. The PI3K/AKT/mTOR pathway upregulation has been linked to radiotherapy resistance. We reviewed the current literature exploring the role of inhibiting targets along this pathway, in enhancing radiotherapy response. We identified several studies using in vitro cancer cell lines, in vivo tumour xenografts and a few Phase I/II clinical trials. Most of the current evidence in this area comes from glioblastoma multiforme, non-small cell lung cancer, head and neck cancer, colorectal cancer, and prostate cancer. The biological basis for radiosensitivity following pathway inhibition was through inhibited DNA double strand break repair, inhibited cell proliferation, enhanced apoptosis and autophagy as well as tumour microenvironment changes. Dual PI3K/mTOR inhibition consistently demonstrated radiosensitisation of all types of cancer cells. Single pathway component inhibitors and other inhibitor combinations yielded variable outcomes especially within early clinical trials. There is ample evidence from preclinical studies to suggest that direct pharmacological inhibition of the PI3K/AKT/mTOR pathway components can radiosensitise different types of cancer cells. We recommend that future in vitro and in vivo research in this field should focus on dual PI3K/mTOR inhibitors. Early clinical trials are needed to assess the feasibility and efficacy of these dual inhibitors in combination with radiotherapy in brain, lung, head and neck, breast, prostate and rectal cancer patients.

Effect of tongue-strengthening exercises on tongue strength and swallowing-related parameters in chronic radiation-associated dysphagia

BACKGROUND

Radiation-associated dysphagia (RAD) is highly prevalent in head and neck cancer (HNC) patients, with insufficient tongue strength (TS) as a characteristic of this disabling complication. The effects of tongue-strengthening exercises (TSE) on TS, swallowing, and quality of life (QoL) have not been studied in this population.

METHODS

A prospective phase 2 study using an 8 weeks during TSE protocol was carried out in 15 patients with chronic RAD. Outcome parameters were maximal isometric pressure (MIP), TS during swallowing (Pswal), swallowing function, and QoL. All parameters were evaluated at baseline, after 4 and 8 weeks of training, and 4 weeks after the last training session.

RESULTS

MIP increased significantly, without detraining effects. Pswal did not increase significantly, but relevant effect sizes were measured. Swallowing function ameliorated, but did not result in increased functional oral intake, self-reported outcome or QoL.

CONCLUSION

TSE in patients with RAD results in increased strength and swallowing function.

Novel in vitro assay to investigate radiation induced changes in the functionality of human embryonic stem cell-derived neurospheres

Ionizing radiation (IR) is increasingly used for diagnostics and therapy of severe brain diseases. However, IR also has adverse effects on the healthy brain tissue, particularly on the neuronal network. This is true for adults but even more pronounced in the developing brain of unborn and pediatric patients. Epidemiological studies on children receiving radiotherapy showed an increased risk for cognitive decline ranging from mild deficits in academic functioning to severe late effects in intellectual ability and language as a consequence of altered neuronal development and connectivity. To provide a comprehensive approach for the analysis of radiation-induced alterations in human neuronal functionality, we developed an in vitro assay by combining microelectrode array (MEA) analyses and human embryonic stem cell (hESC) derived three-dimensional neurospheres (NS). In our proof of principle study, we irradiated hESC with 1 Gy X-rays and let them spontaneously differentiate into neurons within NS. After the onset of neuronal activity, we recorded and analyzed the activity pattern of the developing neuronal networks. The network activity in NS derived from irradiated hESC was significantly reduced, whereas no differences in molecular endpoints such as cell proliferation and transcript or protein expression analyses were found. Thus, the combination of MEA analysis with a 3D model for neuronal functionality revealed radiation sequela that otherwise would not have been detected. We therefore strongly suggest combining traditional biomolecular methods with the new functional assay presented in this work to improve the risk assessment for IR-induced effects on the developing brain.

Decreased Tongue Volume Post Radiation

OBJECTIVES

To evaluate volume changes within the tongue post chemoradiation therapy (CRT).

STUDY DESIGN

Retrospective review.

SETTING

Academic Medical Center.

SUBJECTS AND METHODS

Subjects included 19 patients that received CRT as the primary treatment for tonsillar or hypopharynx squamous cell carcinoma. Tongue volumes were calculated by three raters from thin slice computed tomography images collected before treatment and up to 29 months post-CRT. Body mass index (BMI) was also collected at each time point.

RESULTS

Inter-rater reliability was high with an ICC of 0.849 (95% CI = 0.773, 0.905). Linear mixed effects modeling showed a mean decrease of 0.45 cm³ (standard error of the mean [SEM] = 0.11) in tongue volume per month post-CRT (P < .001). However, the addition of BMI to the model was significant (χ² (4) = 25.0, P < .001), indicating that BMI was a strong predictor of tongue volume, with a mean decrease of 1.75 cm³ (SEM = 0.49) in tongue volume per unit decrease in BMI (P < .001) and reducing the post-CRT effect on tongue volume decrease per month to 0.23 cm³ (P = .02). BMI significantly (P < .001) decreased by 0.11 units (SEM = 0.02) per month post radiation.

CONCLUSION

Tongue dysfunction and decreased tongue strength are significant contributors to the dysphagia that patients experience after receiving CRT. In this study, both tongue volume and BMI decreased post-CRT; therefore, BMI could potentially be used as a predictor of tongue volume post-CRT.

Dose-Limiting Organs at Risk in Carbon Ion Re-Irradiation of Head and Neck Malignancies: An Individual Risk-Benefit Tradeoff

Background: Carbon ion re-irradiation (CIR) was evaluated to investigate treatment planning and the consequences of individual risk-benefit evaluations concerning dose-limiting organs at risk (OAR). Methods: A total of 115 consecutive patients with recurrent head and neck cancer (HNC) were analyzed after initial radiotherapy and CIR at the same anatomical site. Toxicities were evaluated in line with the Common Terminology Criteria for Adverse Events 4.03. Results: The median maximum cumulative equivalent doses applied in fractions of 2 Gy (EQD2) to the brainstem, optic chiasm, ipsilateral optic nerve, and spinal cord were 56.8 Gy (range 0.94-103.9), 51.4 Gy (range 0-120.3 Gy), 63.6 Gy (range 0-146.1 Gy), and 28.8 Gy (range 0.2-87.7 Gy). The median follow up after CIR was 24.0 months (range 2.5-72.0 months). The cumulative rates of acute and late severe (≥grade III) side effects after CIR were 1.8% and 14.3%. Conclusion: In recurrent HNC, an individual risk-benefit tradeoff is frequently inevitable due to unfavorable location of tumors in close proximity to vital OAR. There are uncertainties about the dose tolerance of OAR after CIR, which warrant increased awareness about the potential treatment toxicity and further studies on heavy ion re-irradiation.

Prevalence of Human Papillomavirus (HPV) Infection and the Association with Survival in Saudi Patients with Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) shows wide disparities, association with human papillomavirus (HPV) infection, and prognosis. We aimed at determining HPV prevalence, and its prognostic association with overall survival (OS) in Saudi HNSCC patients. The study included 285 oropharyngeal and oral-cavity HNSCC patients. HPV was detected using HPV Linear-Array and RealLine HPV-HCR. In addition, p16INK4a (p16) protein overexpression was evaluated in 50 representative cases. Oropharyngeal cancers were infrequent (10%) compared to oral-cavity cancers (90%) with no gender differences. Overall, HPV-DNA was positive in 10 HNSCC cases (3.5%), mostly oropharyngeal (21%). However, p16 expression was positive in 21 cases of the 50 studied (42%) and showed significantly higher OS (p = 0.02). Kaplan–Meier univariate analysis showed significant associations between patients’ OS and age (p < 0.001), smoking (p = 0.02), and tumor stage (p < 0.001). A Cox proportional hazard multivariate analysis confirmed the significant associations with age, tumor stage, and also treatment (p < 0.01). In conclusion, HPV-DNA prevalence was significantly lower in our HNSCC patients than worldwide 32–36% estimates (p ≤ 0.001). Although infrequent, oropharyngeal cancer increased over years and showed 21% HPV-DNA positivity, which is close to the worldwide 36–46% estimates (p = 0.16). Besides age, smoking, tumor stage, and treatment, HPV/p16 status was an important determinant of patients’ survival. The HPV and/or p16 positivity patients had a better OS than HPV/p16 double-negative patients (p = 0.05). Thus, HPV/p16 status helps improve prognosis by distinguishing between the more favorable p16/HPV positive and the less favorable double-negative tumors.

Adaptive Responses to Monotherapy in Head and Neck Cancer: Interventions for Rationale-Based Therapeutic Combinations

Most Phase II and III clinical trials in head and neck cancer (HNC) combine two or more treatment modalities, which are based, in part, on knowledge of the molecular mechanisms of innate and acquired resistance to monotherapy. In this review, we describe the range of tumor-cell autonomously derived (intrinsic) and tumor-microenvironment-derived (extrinsic) acquired-resistance mechanisms to various FDA-approved monotherapies for HNC. Specifically, we describe how tumor cells and the tumor microenvironment (TME) respond to radiation, chemotherapy, targeted therapy (cetuximab), and immunotherapies [programmed cell death 1 (PD-1) inhibitors] and adapt to the selective pressure of these monotherapies. Due to the diversity of adaptive responses to monotherapy, monitoring the response to treatment in patients is critical to understand the path that leads to resistance and to guide the optimal therapeutic drug combinations in the clinical setting. We envisage that applying such a rationale-based therapeutic strategy will improve treatment efficacy in HNC patients.

Advances in the Management of HPV-Related Oropharyngeal Cancer

Patients with human papillomavirus- (HPV-) related oropharyngeal squamous cell carcinoma (OPSCC) have a better prognosis than HPV-negative OPSCC when treated with standard high-dose cisplatin-based chemoradiotherapy. Consistent with this assertion and due to younger age at diagnosis, novel approaches to minimize treatment sequelae while preserving survival outcomes become of paramount importance. Here, we critically reviewed the evidence-based literature supporting the deintensification strategies in HPV-related OPSCC management, including radiotherapy dose and/or volume reduction, replacement of cisplatin radiosensitising chemotherapy, and the use of transoral surgery. Undoubtedly, further researches are needed before changing the standard of care in this setting of patients.

Therapeutic efficacy of intra-tumor AvidinOX and low systemic dose biotinylated cetuximab, with and without cisplatin, in an orthotopic model of head and neck cancer

In a previous study, the efficacy of low intraperitoneal doses of biotinylated cetuximab (bCet) in mice with subcutaneous tumor xenografts of human head and neck cancer (HNC) treated intra-tumors with AvidinOX was reported. Taking into account that the current standard treatment for HNC is the combination of cetuximab and cisplatin, the present study investigated the activity of AvidinOX-targeted bCet with and without cisplatin in an orthotopic model. The results confirmed that administration of intra-tumor AvidinOX makes an otherwise inactive dose of bCet effective in reducing tumor growth, and the addition of a low dose of cisplatin further improved tumor growth inhibition. Supporting the in vivo data, immunohistochemical staining of tumor masses from mice treated with AvidinOX, bCet and cisplatin exhibited the highest tumor cell damage and the lowest angiogenic activity among all treatment groups, measured as the number of γ-H2A.X and cleaved caspase-3-positive cells, and vascular endothelial growth factor-C and platelet and endothelial cell adhesion molecule 1-positive cells, respectively. AvidinOX is currently under clinical investigation to assess its use in delivering radioactive biotin to inoperable tumor lesions (ClinicalTrials.gov: NCT02053324 and NCT03188328). The present study further supported the potential clinical use of AvidinOX to target low bCet doses to inoperable tumor lesions, with or without an additional low dose of cisplatin. Since low doses of highly expensive monoclonal antibodies become effective with AvidinOX and low dose cisplatin, such therapies promise to be cheaper and less toxic than current treatments.

Real-world treatment patterns and outcomes of patients with stage IV squamous cell carcinoma of the head and neck

Aim: To understand the treatment patterns and outcomes for stage IV squamous cell carcinoma of the head and neck, patients receiving second-line or later drug therapy. Materials & methods: Real-world data were collected from 1152 patients in the USA, France, Germany and the UK through a retrospective chart analysis and patient-reported outcomes were collected using validated questionnaires in a subgroup of patients. Results: Forty-four percent of patients had stage IVA/B disease. A total of 77, 19 and 3% of patients had received two, three and four plus lines of active drug treatment. Platinum- and cetuximab-based regimens were common at early treatment lines. Time to progression was short (5.2 months post first line), survival rates low and patient-reported health status poor. Conclusion: Novel therapies that could improve clinical and patient-reported outcomes would address a significant unmet need.

Multidisciplinary team in head and neck cancer: a management model

Nowadays, the multidisciplinary team (MDT) is an essential component for oncologic disease management. Its benefit is also extensively recognized in head and neck cancer (HNC) community, due to tumor rarity and complex treatment. A well-defined MDT management serves as a stable point to define the better strategy and offers a chance to optimize HNC clinical outcomes and patient's quality of life. We explored both mandatory and additional requirements for establishing a high-quality MDT. Then we proposed an example of HNC MDT organization. The aim is to contribute to the best way to systematize HNC care.

Radiation effects on male fertility

BACKGROUND

Spermatogenesis is a process of dynamic cell differentiation. Ionizing radiation impairs spermatogenesis, and spermatogonia are more radiosensitive than spermatocytes or spermatids. Consistent with this assumption and due to improvement in tumor curability, nowadays, fertility preservation represents a public health need.

OBJECTIVES

To discuss radiotherapy-induced risk to male fertility and raise oncologic awareness of male fertility in daily clinical practice.

MATERIALS AND METHODS

PubMed and Clinicaltrials.gov databases were searched for papers in English.

RESULTS

We provide an overview of clinical landscape. Four main issues were proposed: (i) spermatogenesis and radiobiological general concepts; (ii) impairment of spermatogenesis; (iii) impairment of testosterone-producing Leydig cells; (iv) clinical radiotherapy evidence in oncology.

CONCLUSION

This review can be useful in daily clinical work and offer some directions for future research.

Radiation therapy in renal cell carcinoma

Renal cell carcinoma (RCC) is classically regarded as extremely resistant to classical fractionated radiation therapy (RT). Nowadays, there is convincing data supporting RCC radiosensitivity to high fraction doses, which may represent an ideal issue for new treatment strategies in primary and oligometastatic RCC disease. This review discusses the role of RT in RCC and its potential therapeutic scenario focusing on the most interesting clinical trials.