Advances in Radiotherapy for Head and Neck Cancer

Cluster-based radiomics reveal spatial heterogeneity of bevacizumab response for treatment of radiotherapy-induced cerebral necrosis

Background

Bevacizumab is used in the treatment of radiation necrosis (RN), which is a debilitating toxicity following head and neck radiotherapy. However, there is no biomarker to predict if a patient would respond to bevacizumab.

Purpose

We aimed to develop a cluster-based radiomics approach to characterize the spatial heterogeneity of RN and map their responses to bevacizumab.

Methods

118 consecutive nasopharyngeal carcinoma patients diagnosed with RN were enrolled. We divided 152 lesions from the patients into 101 for training, and 51 for validation. We extracted voxel-level radiomics features from each lesion segmented on T1-weighted+contrast and T2 FLAIR sequences of pre- and post-bevacizumab magnetic resonance images, followed by a three-step analysis involving individual- and population-level clustering, before delta-radiomics to derive five radiomics clusters within the lesions. We tested the association of each cluster with response to bevacizumab and developed a clinico-radiomics model using clinical predictors and cluster-specific features.

Results

71 (70.3%) and 34 (66.7%) lesions had responded to bevacizumab in the training and validation datasets, respectively. Two radiomics clusters were spatially mapped to the edema region, and the volume changes were significantly associated with bevacizumab response (OR:11.12 [95% CI: 2.54-73.47], P = 0.004; and 1.63[1.07-2.78], P = 0.042). The combined clinico-radiomics model based on textural features extracted from the most significant cluster improved the prediction of bevacizumab response, compared with a clinical-only model (AUC:0.755 [0.645-0.865] to 0.852 [0.764-0.940], training; 0.708 [0.554-0.861] to 0.816 [0.699-0.933], validation).

Conclusion

Our radiomics approach yielded intralesional resolution, enabling a more refined feature selection for predicting bevacizumab efficacy in the treatment of RN.

Smart nanozymes coupled with dynamic magnet field and laser exposures for cancer therapy

Developing nanozymes for cancer therapy has attracted great attention from researchers. However, enzymes-loaded magnetic particles triggered by both a low-frequency vibrating magnetic field (VMF) and laser for inhibiting tumor growth have never been reported. Herein, we developed a magnetic nanozyme with 3D flower-like nanostructures for cancer therapy. Specifically, the flower-like nanozymes exposed to a VMF could efficiently damage the mitochondrial membrane and cell structure, and inhibit tumor growth through magneto-mechanical force. In parallel, magnetic nanozymes in a weak acid environment containing glucose could generate abundant hydrogen peroxide through glucose oxidase-catalyzed oxidation of glucose, and further significantly promote the Fenton reaction. Interestingly, both glucose oxidase- and Fenton-based catalytic reactions were significantly promoted by the VMF exposure. Flower-like magnetic nanospheres upon a near-infrared laser irradiation could also damage cancer cells and tumor tissues through photothermal effect. The cell-killing efficiency of magnetic nanozymes triggered by the VMF or laser significantly increased in comparison with that of nanozymes without exposures. Mouse tumors grown after injection with magnetic nanozymes was inhibited in a significant way or the tumors disappeared after exposure to a VMF and laser due to the synergistic effect of four major stimuli, viz., magneto-mechanical force, photothermal conversion, improved Fenton reaction, and intratumoral glucose consumption-based starvation effect. This is a great platform that may be suitable for treating many solid tumors.

The effect of simulated radiation induced fibrosis on tongue protrusion

Radiation therapy (RT) is an important adjuvant and primary treatment modality for head and neck cancers. A severe side effect of RT is fibrosis or scarring of muscle tissues of the oral cavity including the tongue. Previous studies have demonstrated that increased radiation doses to the oral cavity structures have led to decrements in function, hypothesized to result from changes in muscle tissue properties that affect the tongue's function. To understand the complex relationship between tongue muscle fibrosis and tongue function, the current study used a virtual biomechanical model of the tongue. Fibrosis parameters including density (high, low), area (large, small) and location (946 node centres) were systematically varied in the model to test its impact on a target tongue tip motion (protrusion). The impact of fibrosis lesion parameters on three directional components of the tip (anterior-inferior, lateral-medial, and superior-inferior) were analyzed using multi linear regression models. Increases in density and area of fibrosis significantly predicted tongue protrusion movements compared to baseline. In the anterior-posterior direction, reductions in the tongue protrusion were observed. In the inferior-superior direction, the tongue height remained above baseline for the majority of cases. In the lateral-medial direction, ipsilateral deviations were observed. The location of fibrosis modulated these three main effects by either amplifying the observed effect or minimizing it. The findings support the hypothesis that changes in muscle tissue properties because of fibrosis impact tongue function. Increases in density and area of fibrosis impact key muscles in the target motion. The range of modulating effects of the lesion location (i.e., either amplifying or minimizing certain impact patterns) highlights the intricacy of tongue anatomy/soft tissue biomechanics and may suggest that lesions in any location will compromise the tongue's movement.

Molecular mechanisms of poor osseointegration in irradiated bone: In vivo study in a rat tibia model

AIM

Radiotherapy is associated with cell depletion and loss of blood supply, which are linked to compromised bone healing. However, the molecular events underlying these effects at the tissue-implant interface have not been fully elucidated. This study aimed to determine the major molecular mediators associated with compromised osseointegration due to previous exposure to radiation.

MATERIALS AND METHODS

Titanium implants were placed in rat tibiae with or without pre-exposure to 20 Gy irradiation. Histomorphometric, biomechanical, quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay analyses were performed at 1 and 4 weeks after implantation.

RESULTS

The detrimental effects of irradiation were characterized by reduced bone-implant contact and removal torque. Furthermore, pre-exposure to radiation induced different molecular dysfunctions such as (i) increased expression of pro-inflammatory (Tnf) and osteoclastic (Ctsk) genes and decreased expression of the bone formation (Alpl) gene in implant-adherent cells; (ii) increased expression of bone formation (Alpl and Bglap) genes in peri-implant bone; and (iii) increased expression of pro-inflammatory (Tnf) and pro-fibrotic (Tgfb1) genes in peri-implant soft tissue. The serum levels of pro-inflammatory, bone formation and bone resorption proteins were greater in the irradiated rats.

CONCLUSIONS

Irradiation causes the dysregulation of multiple biological activities, among which perturbed inflammation seems to play a common role in hindering osseointegration.

Radiobiology of Proton Therapy in Human Papillomavirus-Negative and Human Papillomavirus-Positive Head and Neck Cancer Cells

Photon-based radiotherapy (XRT) is one of the most frequently used treatment modalities for HPV-negative and HPV-positive locally advanced head and neck squamous cell carcinoma (HNSCC). However, locoregional recurrences and normal RT-associated toxicity remain major problems for these patients. Proton therapy (PT), with its dosimetric advantages, can present a solution to the normal toxicity problem. However, issues concerning physical delivery and the lack of insights into the underlying biology of PT hamper the full exploitation of PT. Here, we assessed the radiobiological processes involved in PT in HPV-negative and HPV-positive HNSCC cells. We show that PT and XRT activate the DNA damage-repair and stress response in both HPV-negative and HPV-positive cells to a similar extent. The activation of these major radiobiological mechanisms resulted in equal levels of clonogenic survival and mitotic cell death. Altogether, PT resulted in similar biological effectiveness when compared to XRT. These results emphasize the importance of dosimetric parameters when exploiting the potential of increased clinical effectiveness and reduced normal tissue toxicity in PT treatment.

Development and Validation of a 3D Resnet Model for Prediction of Lymph Node Metastasis in Head and Neck Cancer Patients

The accurate diagnosis and staging of lymph node metastasis (LNM) are crucial for determining the optimal treatment strategy for head and neck cancer patients. We aimed to develop a 3D Resnet model and investigate its prediction value in detecting LNM. This study enrolled 156 head and neck cancer patients and analyzed 342 lymph nodes segmented from surgical pathologic reports. The patients' clinical and pathological data related to the primary tumor site and clinical and pathology T and N stages were collected. To predict LNM, we developed a dual-pathway 3D Resnet model incorporating two Resnet models with different depths to extract features from the input data. To assess the model's performance, we compared its predictions with those of radiologists in a test dataset comprising 38 patients. The study found that the dimensions and volume of LNM + were significantly larger than those of LNM-. Specifically, the Y and Z dimensions showed the highest sensitivity of 84.6% and specificity of 72.2%, respectively, in predicting LNM + . The analysis of various variations of the proposed 3D Resnet model demonstrated that Dual-3D-Resnet models with a depth of 34 achieved the highest AUC values of 0.9294. In the validation test of 38 patients and 86 lymph nodes dataset, the 3D Resnet model outperformed both physical examination and radiologists in terms of sensitivity (80.8% compared to 50.0% and 91.7%, respectively), specificity(90.0% compared to 88.5% and 65.4%, respectively), and positive predictive value (77.8% compared to 66.7% and 55.0%, respectively) in detecting individual LNM + . These results suggest that the 3D Resnet model can be valuable for accurately identifying LNM + in head and neck cancer patients. A prospective trial is needed to evaluate further the role of the 3D Resnet model in determining LNM + in head and neck cancer patients and its impact on treatment strategies and patient outcomes.

IFN-γ promotes radioresistant Nestin-expressing progenitor regeneration in the developing cerebellum by augmenting Shh ligand production

BACKGROUND

Patients with brain tumors, especially pediatric brain tumors such as cerebellar medulloblastoma, always suffer from the severe side effects of radiotherapy. Regeneration of neural cells in irradiation-induced cerebellar injury has been reported, but the underlying mechanism remains elusive.

METHODS

We established an irradiation-induced developing cerebellum injury model in neonatal mice. Microarray, KEGG analysis and semi in vivo slice culture were performed for mechanistic study.

RESULTS

Nestin-expressing progenitors (NEPs) but not granule neuron precursors (GNPs) were resistant to irradiation and able to regenerate after irradiation. NEPs underwent less apoptosis but similar DNA damage following irradiation compared with GNPs. Subsequently, they started to proliferate and contributed to granule neurons regeneration dependent on the sonic hedgehog (Shh) pathway. In addition, irradiation increased Shh ligand provided by Purkinje cells. And microglia accumulated in the irradiated cerebellum producing more IFN-γ, which augmented Shh ligand production to promote NEP proliferation.

CONCLUSIONS

NEP was radioresistant and regenerative. IFN-γ was increased post irradiation to upregulate Shh ligand, contributing to NEP regeneration. Our study provides insight into the mechanisms of neural cell regeneration in irradiation injury of the developing cerebellum and will help to develop new therapeutic targets for minimizing the side effects of radiotherapy for brain tumors.

Treatment planning comparison for head and neck cancer between photon, proton, and combined proton-photon therapy - From a fixed beam line to an arc

BACKGROUND AND PURPOSE

This study investigates whether combined proton-photon therapy (CPPT) improves treatment plan quality compared to single-modality intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT) for head and neck cancer (HNC) patients. Different proton beam arrangements for CPPT and IMPT are compared, which could be of specific interest concerning potential future upright-positioned treatments. Furthermore, it is evaluated if CPPT benefits remain under inter-fractional anatomical changes for HNC treatments.

MATERIAL AND METHODS

Five HNC patients with a planning CT and multiple (4-7) repeated CTs were studied. CPPT with simultaneously optimized photon and proton fluence, single-modality IMPT, and IMRT treatment plans were optimized on the planning CT and then recalculated and reoptimized on each repeated CT. For CPPT and IMPT, plans with different degrees of freedom for the proton beams were optimized. Fixed horizontal proton beam line (FHB), gantry-like, and arc-like plans were compared.

RESULTS

The target coverage for CPPT without adaptation is insufficient (average V95%=88.4 %), while adapted plans can recover the initial treatment plan quality for target (average V95%=95.5 %) and organs-at-risk. CPPT with increased proton beam flexibility increases plan quality and reduces normal tissue complication probability of Xerostomia and Dysphagia. On average, Xerostomia NTCP reductions compared to IMRT are -2.7 %/-3.4 %/-5.0 % for CPPT FHB/CPPT Gantry/CPPT Arc. The differences for IMPT FHB/IMPT Gantry/IMPT Arc are + 0.8 %/-0.9 %/-4.3 %.

CONCLUSION

CPPT for HNC needs adaptive treatments. Increasing proton beam flexibility in CPPT, either by using a gantry or an upright-positioned patient, improves treatment plan quality. However, the photon component is substantially reduced, therefore, the balance between improved plan quality and costs must be further determined.

Considerations for study design in the DAHANCA 35 trial of protons versus photons for head and neck cancer

Proton radiotherapy offers a dosimetric advantage compared to photon therapy in sparing normal tissue, but the clinical evidence for toxicity reductions in the treatment of head and neck cancer is limited. The Danish Head and Neck Cancer Group (DAHANCA) has initiated the DAHANCA 35 randomised trial to clarify the value of proton therapy (NCT04607694). The DAHANCA 35 trial is performed in an enriched population of patients selected by an anticipated benefit of proton therapy to reduce the risk of late dysphagia or xerostomia based on normal tissue complication probability (NTCP) modelling. We present our considerations on the trial design and a test of the selection procedure conducted before initiating the randomised study.

Impact of consensus guidelines on delineation of primary tumor clinical target volume (CTVp) for head and neck cancer: Results of a national review project

BACKGROUND AND PURPOSE

A significant interobserver variability (IOV) for clinical target volume of the primary tumor (CTVp) delineation was shown in a previous national review project. Since then, international expert consensus guidelines (CG) for the delineation of CTVp were published. The aim of this follow-up study was to 1) objectify the extent of implementation of the CG, 2) assess its impact on delineation quality and consistency, 3) identify any remaining ambiguities.

MATERIALS AND METHODS

All Belgian RT departments were invited to complete an online survey and submit CTVp for 5 reference cases. Organs at risk and GTV of the primary tumor were predefined. Margins, volumes, IOV between all participating centers (IOVall) and IOV compared to a reference consensus delineation (IOVref) were calculated and compared to the previous analysis. A qualitative analysis was performed assessing the correct interpretation of the CG for each case.

RESULTS

17 RT centers completed both survey and delineations, of which 88% had implemented CG. Median DSCref for CTVp_total was 0.80-0.92. IOVall and IOVref improved significantly for the centers following CG (p = 0.005). IOVref for CTVp_high was small with a DSC higher than 0.90 for all cases. A significant volume decrease for the CTVp receiving 70 Gy was observed. Interpretation of CG was more accurate for (supra)glottic carcinoma. 60% of the radiation oncologists thinks clarification of CG is indicated.

CONCLUSION

Implementation of consensus guidelines for CTVp delineation is already fairly advanced on a national level, resulting in significantly increased delineation uniformity. The accompanying substantial decrease of CTV receiving high dose RT calls for caution and correct interpretation of CG. Clarification of the existing guidelines seems appropriate especially for oropharyngeal and hypopharyngeal carcinoma.

Plan robustness and RBE influence for proton dose painting by numbers for head and neck cancers

PURPOSE

To investigate the feasibility of dose painting by numbers (DPBN) with respect to robustness for proton therapy for head and neck cancers (HNC), and to study the influence of variable RBE on the TCP and OAR dose burden.

METHODS AND MATERIALS

Data for 19 patients who have been scanned pretreatment with PET-FDG and subsequently treated with photon therapy were used in the study. A dose response model developed for photon therapy was implemented in a TPS, allowing DPBN plans to be created. Conventional homogeneous dose and DPBN plans were created for each patient, optimized with either fixed RBE = 1.1 or a variable RBE model. Robust optimization was used to create clinically acceptable plans. To estimate the maximum potential loss in TCP due to actual SUV variations from the pre-treatment imaging, we applied a test case with randomized SUV distribution.

RESULTS

Regardless of the use of variable RBE for optimization or evaluation, a statistically significant increase (p < 0.001) in TCP was found for DPBN plans as compared to homogeneous dose plans. Randomizing the SUV distribution decreased the TCP for all plans. A correlation between TCP increase and variance of the SUV distribution and target volume was also found.

CONCLUSION

DPBN for protons and HNC is feasible and could lead to a TCP gain. Risks associated with the temporal variation of SUV distributions could be mitigated by imposing minimum doses to targets. The correlation found between TCP increase and SUV variance and target volume may be used for patient selection.

Evolving role of novel radiosensitizers and immune checkpoint inhibitors in (chemo)radiotherapy of locally advanced head and neck squamous cell carcinoma

Chemoradiotherapy (CRT) remains the standard treatment for locally advanced head and neck squamous cell carcinoma (LA-HNSCC), based on numerous randomized controlled trials and meta-analyses demonstrating that CRT improved locoregional control and overall survival. Achieving locoregional control is a crucial outcome for the treatment of HNSCC, as it directly affects patient quality of life and survival. Cisplatin is the recommended standard-of-care radiosensitizing agent for LA-HNSCC patients undergoing CRT, whereas cetuximab-radiotherapy is reserved for cisplatin-ineligible patients. Immune checkpoint inhibitors (ICIs) have shown promise in the treatment of recurrent or metastatic HNSCC. However, the combination of ICIs with standard-of-care radiotherapy or chemoradiotherapy in LA-HNSCC has not demonstrated significant improvement in survivals. Over the past few decades, significant advancements in radiotherapy techniques have allowed for more precise and effective radiation delivery while minimizing toxicity to surrounding normal tissues. These advances have led to improved treatment outcomes and quality of life for patients with LA-HNSCC. Despite these advancements, the development of novel radiosensitizing agents remains an unmet need. This review discusses the mechanism of radiotherapy and its impact on the immune system. We summarize the latest clinical development of novel radiosensitizing agents, such as SMAC mimetics, DDR pathway inhibitors, and CDK4/6 inhibitor. We also elucidate the emerging evidence of combining ICIs with radiotherapy or chemoradiotherapy in curative settings for LA-HNSCC, using both concurrent and sequential approaches. Lastly, we discuss the future direction of systemic therapy in combination with radiotherapy in treatment for LA-HNSCC.

Twenty Years of Advancements in a Radiotherapy Facility: Clinical Protocols, Technology, and Management

BACKGROUND

Hypo-fractionation can be an effective strategy to lower costs and save time, increasing patient access to advanced radiation therapy. To demonstrate this potential in practice within the context of temporal evolution, a twenty-year analysis of a representative radiation therapy facility from 2003 to 2022 was conducted. This analysis utilized comprehensive data to quantitatively evaluate the connections between advanced clinical protocols and technological improvements. The findings provide valuable insights to the management team, helping them ensure the delivery of high-quality treatments in a sustainable manner.

METHODS

Several parameters related to treatment technique, patient positioning, dose prescription, fractionation, equipment technology content, machine workload and throughput, therapy times and patients access counts were extracted from departmental database and analyzed on a yearly basis by means of linear regression.

RESULTS

Patients increased by 121 ± 6 new per year (NPY). Since 2010, the incidence of hypo-fractionation protocols grew thanks to increasing Linac technology. In seven years, both the average number of fractions and daily machine workload decreased by -0.84 ± 0.12 fractions/year and -1.61 ± 0.35 patients/year, respectively. The implementation of advanced dose delivery techniques, image guidance and high dose rate beams for high fraction doses, currently systematically used, has increased the complexity and reduced daily treatment throughput since 2010 from 40 to 32 patients per 8 h work shift (WS8). Thanks to hypo-fractionation, such an efficiency drop did not affect NPY, estimating 693 ± 28 NPY/WS8, regardless of the evaluation time. Each newly installed machine was shown to add 540 NPY, while absorbing 0.78 ± 0.04 WS8. The COVID-19 pandemic brought an overall reduction of 3.7% of patients and a reduction of 0.8 fractions/patient, to mitigate patient crowding in the department.

CONCLUSIONS

The evolution of therapy protocols towards hypo-fractionation was supported by the use of proper technology. The characteristics of this process were quantified considering time progression and organizational aspects. This strategy optimized resources while enabling broader access to advanced radiation therapy. To truly value the benefit of hypo-fractionation, a reimbursement policy should focus on the patient rather than individual treatment fractionation.

Towards unravelling biological mechanisms behind radiation-induced oral mucositis via mass spectrometry-based proteomics

Objective

Head and neck cancer (HNC) accounts for almost 890,000 new cases per year. Radiotherapy (RT) is used to treat the majority of these patients. A common side-effect of RT is the onset of oral mucositis, which decreases the quality of life and represents the major dose-limiting factor in RT. To understand the origin of oral mucositis, the biological mechanisms post-ionizing radiation (IR) need to be clarified. Such knowledge is valuable to develop new treatment targets for oral mucositis and markers for the early identification of "at-risk" patients.

Methods

Primary keratinocytes from healthy volunteers were biopsied, irradiated in vitro (0 and 6 Gy), and subjected to mass spectrometry-based analyses 96 h after irradiation. Web-based tools were used to predict triggered biological pathways. The results were validated in the OKF6 cell culture model. Immunoblotting and mRNA validation was performed and cytokines present in cell culture media post-IR were quantified.

Results

Mass spectrometry-based proteomics identified 5879 proteins in primary keratinocytes and 4597 proteins in OKF6 cells. Amongst them, 212 proteins in primary keratinocytes and 169 proteins in OKF6 cells were differentially abundant 96 h after 6 Gy irradiation compared to sham-irradiated controls. In silico pathway enrichment analysis predicted interferon (IFN) response and DNA strand elongation pathways as mostly affected pathways in both cell systems. Immunoblot validations showed a decrease in minichromosome maintenance (MCM) complex proteins 2-7 and an increase in IFN-associated proteins STAT1 and ISG15. In line with affected IFN signalling, mRNA levels of IFNβ and interleukin 6 (IL-6) increased significantly following irradiation and also levels of secreted IL-1β, IL-6, IP-10, and ISG15 were elevated.

Conclusion

This study has investigated biological mechanisms in keratinocytes post-in vitro ionizing radiation. A common radiation signature in keratinocytes was identified. The role of IFN response in keratinocytes along with increased levels of pro-inflammatory cytokines and proteins could hint towards a possible mechanism for oral mucositis.

PKCδ regulates chromatin remodeling and DNA repair through SIRT6

Protein kinase C delta (PKCδ) is a ubiquitous kinase whose function is defined in part by localization to specific cellular compartments. Nuclear PKCδ is both necessary and sufficient for IR-induced apoptosis, while inhibition of PKCδ activity provides radioprotection in vivo. How nuclear PKCδ regulates DNA-damage induced cell death is poorly understood. Here we show that PKCδ regulates histone modification, chromatin accessibility, and double stranded break (DSB) repair through a mechanism that requires SIRT6. Overexpression of PKCδ promotes genomic instability and increases DNA damage and apoptosis. Conversely, depletion of PKCδ increases DNA repair via non-homologous end joining (NHEJ) and homologous recombination (HR) as evidenced by more rapid formation of NHEJ (DNA-PK) and HR (Rad51) DNA damage foci, increased expression of repair proteins, and increased repair of NHEJ and HR fluorescent reporter constructs. Nuclease sensitivity indicates that PKCδ depletion is associated with more open chromatin, while overexpression of PKCδ reduces chromatin accessibility. Epiproteome analysis revealed that PKCδ depletion increases chromatin associated H3K36me2, and reduces ribosylation of KDM2A and chromatin bound KDM2A. We identify SIRT6 as a downstream mediator of PKCδ. PKCδ-depleted cells have increased expression of SIRT6, and depletion of SIRT6 reverses the changes in chromatin accessibility, histone modification and NHEJ and HR DNA repair seen with PKCδ-depletion. Furthermore, depletion of SIRT6 reverses radioprotection in PKCδ-depleted cells. Our studies describe a novel pathway whereby PKCδ orchestrates SIRT6-dependent changes in chromatin accessibility to increase DNA repair, and define a mechanism for regulation of radiation-induced apoptosis by PKCδ.

Prognostic and predictive values of baseline and mid-treatment FDG-PET in oropharyngeal carcinoma treated with primary definitive (chemo)radiation and impact of HPV status: review of current literature and emerging roles

BACKGROUND AND PURPOSE

This study provides a review of the literature assessing whether semiquantitative PET parameters acquired at baseline and/or during definitive (chemo)radiotherapy ("prePET" and "iPET") can predict survival outcomes in patients with oropharyngeal squamous cell carcinoma (OPC), and the impact of human papilloma virus (HPV) status.

MATERIAL AND METHODS

A literature search was carried out using PubMed and Embase between 2001 to 2021 in accordance with PRISMA.

RESULTS

The analysis included 22 FDG-PET/CT studies^1-22, 19 pre-PET and 3 both pre-PET and iPET^14,18,20,. The analysis involved 2646 patients, of which 1483 are HPV-positive (17 studies: 10 mixed and 7 HPV-positive only), 589 are HPV-negative, and 574 have unknown HPV status. Eighteen studies found significant correlations of survival outcomes with pre-PET parameters, most commonly primary or "Total" (combined primary and nodal) metabolic tumour volume and/or total lesional glycolysis. Two studies could not establish significant correlations and both employed SUVmax only. Two studies also could not establish significant correlations when taking into account of the HPV-positive population only. Because of the heterogeneity and lack of standardized methodology, no conclusions on optimal cut-off values can be drawn. Ten studies specifically evaluated HPV-positive patients: five showed positive correlation of pre-PET parameters and survival outcomes, but four of these studies did not include advanced T or N staging in multivariate analysis^1,6,15,22, and two studies only showed positive correlations after excluding high risk patients with smoking history⁷ or adverse CT features²². Two studies found that prePET parameters predicted treatment outcomes only in HPV-negative but not HPV-positive patients^10,16. Two studies found that iPET parameters could predict outcomes in HPV-positive patients but not prePET parameters^14,18.

CONCLUSION

The current literature supports high pre-treatment metabolic burden prior to definitive (chemo)radiotherapy can predict poor treatment outcomes for HPV-negative OPC patients. Evidence is conflicting and currently does not support correlation in HPV-positive patients.

Identification of an individualized therapy prognostic signature for head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) are the most common cancers in the head and neck. Therapeutic response-related genes (TRRGs) are closely associated with carcinogenesis and prognosis in HNSCC. However, the clinical value and prognostic significance of TRRGs are still unclear. We aimed to construct a prognostic risk model to predict therapy response and prognosis in TRRGs-defined subgroups of HNSCC.

METHODS

The multiomics data and clinical information of HNSCC patients were downloaded from The Cancer Genome Atlas (TCGA). The profile data GSE65858 and GSE67614 chip was downloaded from public functional genomics data Gene Expression Omnibus (GEO). Based on TCGA-HNSC database, patients were divided into a remission group and a non-remission group according to therapy response, and differentially expressed TRRGs between those two groups were screened. Using Cox regression analysis and Least absolute shrinkage and selection operator (LASSO) analysis, candidate TRRGs that can predict the prognosis of HNSCC were identified and used to construct a TRRGs-based signature and a prognostic nomogram.

RESULT

A total of 1896 differentially expressed TRRGs were screened, including 1530 upregulated genes and 366 downregulated genes. Then, 206 differently expressed TRRGs that was significantly associated with the survival were chosen using univariate Cox regression analysis. Finally, a total of 20 candidate TRRGs genes were identified by LASSO analysis to establish a signature for risk prediction, and the risk score of each patient was calculated. Patients were divided into a high-risk group (Risk-H) and a low-risk group (Risk-L) based on the risk score. Results showed that the Risk-L patients had better overall survival (OS) than Risk-H patients. Receiver operating characteristic (ROC) curve analysis revealed great predictive performance for 1-, 3-, and 5-year OS in TCGA-HNSC and GEO databases. Moreover, for patients treated with post-operative radiotherapy, Risk-L patients had longer OS and lower recurrence than Risk-H patients. The nomogram involves risk score and other clinical factors had good performance in predicting survival probability.

CONCLUSIONS

The proposed risk prognostic signature and Nomogram based on TRRGs are novel promising tools for predicting therapy response and overall survival in HNSCC patients.

Noninvasive Monitoring of Radiation-Induced Salivary Gland Vascular Injury

Xerostomia is a common side effect of radiation therapy (RT) in patients with head and neck cancer. However, limited information is available on the temporal dynamics of parenchymal and vascular changes in salivary glands following RT. To address this gap in knowledge, we conducted experimental studies in mice employing ultrasound (US) with coregistered photoacoustic imaging (PAI) to noninvasively assess the early and late changes in salivary gland size, structure, vascularity, and oxygenation dynamics following RT. Multiparametric US-PAI of salivary glands was performed in immune-deficient and immune-competent mice before and after RT along with correlative sialometry and ex vivo histologic-immunohistochemical validation. US revealed reduction in gland volume and an early increase in vascular resistance postradiation. This was accompanied by a reduction in glandular oxygen consumption on PAI. Imaging data correlated strongly with salivary secretion and histologic evidence of acinar damage. The magnitude and kinetics of radiation response were impacted by host immune status, with immunodeficient mice showing early and more pronounced vascular injury and DNA damage response compared to immunocompetent animals. Our findings demonstrate the ability of noninvasive US-PAI to monitor dynamic changes in salivary gland hemodynamics following radiation and highlight the impact of the host immune status on salivary gland radiation injury.

Circadian rhythm-related genes index: A predictor for HNSCC prognosis, immunotherapy efficacy, and chemosensitivity

Background

Head and neck squamous cell carcinoma (HNSCC) is the most common head and neck cancer and is highly aggressive and heterogeneous, leading to variable prognosis and immunotherapy outcomes. Circadian rhythm alterations in tumourigenesis are of equal importance to genetic factors and several biologic clock genes are considered to be prognostic biomarkers for various cancers. The aim of this study was to establish reliable markers based on biologic clock genes, thus providing a new perspective for assessing immunotherapy response and prognosis in patients with HNSCC.

Methods

We used 502 HNSCC samples and 44 normal samples from the TCGA-HNSCC dataset as the training set. 97 samples from GSE41613 were used as an external validation set. Prognostic characteristics of circadian rhythm-related genes (CRRGs) were established by Lasso, random forest and stepwise multifactorial Cox. Multivariate analysis revealed that CRRGs characteristics were independent predictors of HNSCC, with patients in the high-risk group having a worse prognosis than those in the low-risk group. The relevance of CRRGs to the immune microenvironment and immunotherapy was assessed by an integrated algorithm.

Results

6-CRRGs were considered to be strongly associated with HNSCC prognosis and a good predictor of HNSCC. The riskscore established by the 6-CRRG was found to be an independent prognostic factor for HNSCC in multifactorial analysis, with patients in the low-risk group having a higher overall survival (OS) than the high-risk group. Nomogram prediction maps constructed from clinical characteristics and riskscore had good prognostic power. Patients in the low-risk group had higher levels of immune infiltration and immune checkpoint expression and were more likely to benefit from immunotherapy.

Conclusion

6-CRRGs play a key predictive role for the prognosis of HNSCC patients and can guide physicians in selecting potential responders to prioritise immunotherapy, which could facilitate further research in precision immuno-oncology.

Artificial intelligence to predict outcomes of head and neck radiotherapy

Head and neck radiotherapy induces important toxicity, and its efficacy and tolerance vary widely across patients. Advancements in radiotherapy delivery techniques, along with the increased quality and frequency of image guidance, offer a unique opportunity to individualize radiotherapy based on imaging biomarkers, with the aim of improving radiation efficacy while reducing its toxicity. Various artificial intelligence models integrating clinical data and radiomics have shown encouraging results for toxicity and cancer control outcomes prediction in head and neck cancer radiotherapy. Clinical implementation of these models could lead to individualized risk-based therapeutic decision making, but the reliability of the current studies is limited. Understanding, validating and expanding these models to larger multi-institutional data sets and testing them in the context of clinical trials is needed to ensure safe clinical implementation. This review summarizes the current state of the art of machine learning models for prediction of head and neck cancer radiotherapy outcomes.

Osteoradionecrosis of the Jaw Following Proton Radiation Therapy for Patients With Head and Neck Cancer

Importance

Proton radiation therapy (PRT) has reduced radiation-induced toxic effects, such as mucositis and xerostomia, over conventional photon radiation therapy, leading to significantly improved quality of life in patients with head and neck cancers. However, the prevalence of osteoradionecrosis (ORN) of the jaw following PRT in these patients is less clear.

Objective

To report the prevalence and clinical characteristics of ORN in patients with oral and oropharyngeal cancer (OOPC) treated with PRT.

Design, Setting, and Participants

This case series reports a single-institution experience (Memorial Sloan Kettering Cancer Center, New York, New York) between November 2013 and September 2019 and included 122 radiation therapy-naive patients with OOPC treated with PRT. Data were analyzed from 2013 to 2019.

Main Outcomes and Measures

Clinical parameters, including sex, age, comorbidities, tumor histology, concurrent chemotherapy, smoking, comorbidities, and preradiation dental evaluation, were obtained from the medical record. Patients with clinical or radiographic signs of ORN were identified and graded using the adopted modified Glanzmann and Grätz grading system. Characteristics of ORN, such as location, clinical presentation, initial stage at diagnosis, etiology, time to diagnosis, management, and clinical outcome at the last follow-up, were also collected.

Results

Of the 122 patients (mean [SD] age, 63 [13] years; 45 [36.9%] women and 77 [63.1%] men) included in this study, 13 (10.6%) developed ORN following PRT during a median (range) follow-up time of 40.6 (<1-101) months. All patients had spontaneous development of ORN. At the time of initial diagnosis, grade 0, grade 1, grade 2, and grade 3 ORN were seen in 2, 1, 9, and 1 patient, respectively. The posterior ipsilateral mandible within the radiation field that received the full planned PRT dose was the most involved ORN site. At a median (range) follow-up of 13.5 (0.2-58.0) months from the time of ORN diagnosis, complete resolution, stable condition, and progression of ORN were seen in 3, 6, and 4 patients, respectively. The 3-year rates of ORN and death in the total cohort were 5.2% and 21.5%, while the 5-year rates of ORN and death were 11.5% and 34.4%, respectively.

Conclusions and Relevance

In this case series, the prevalence of ORN following PRT was found to be 10.6%, indicating that ORN remains a clinical challenge even in the era of highly conformal PRT. Clinicians treating patients with OOPC with PRT should be mindful of this complication.

Dosimetric comparison between VMAT plans using the fast-rotating O-ring linac with dual-layer stacked MLC and helical tomotherapy for nasopharyngeal carcinoma

BACKGROUND

To compare the dosimetric profiles of volumetric modulated arc therapy (VMAT) plans using the fast-rotating O-ring linac (the Halcyon system) based on a dual-layer stacked multi-leaf collimator and helical tomotherapy (HT) for nasopharyngeal cancer (NPCa).

METHODS

For 30 NPCa patients, three sets of RT plans were generated, under the same policy of contouring and dose constraints: HT plan; Halcyon VMAT plan with two arcs (HL_2arc); and Halcyon VMAT plan with four arcs (HL_4arc), respectively. The intended dose schedule was to deliver 67.2 Gy to the planning gross target volume (P-GTV) and 56.0 Gy to the planning clinical target volume (P-CTV) in 28 fractions using the simultaneously integrated boost concept. Target volumes and organ at risks dose metrics were evaluated for all plans. Normal tissue complication probabilities (NTCP) for esophagus, parotid glands, spinal cord, and brain stem were compared.

RESULTS

The HT plan achieved the best dose homogeneity index for both P_GTV and P_CTV, followed by the HL_4arc and L_2arc plans. No significant difference in the dose conformity index (CI) for P_GTV was observed between the HT plan (0.80) and either the HL_2arc plan (0.79) or the HL_4arc plan (0.83). The HL_4arc plan showed the best CI for P_CTV (0.88), followed by the HL_2arc plan (0.83) and the HT plan (0.80). The HL_4arc plan (median, interquartile rage (Q1, Q3): 25.36 (22.22, 26.89) Gy) showed the lowest D_mean in the parotid glands, followed by the HT (25.88 (23.87, 27.87) Gy) and HL_2arc plans (28.00 (23.24, 33.99) Gy). In the oral cavity (OC) dose comparison, the HT (22.03 (19.79, 24.85) Gy) plan showed the lowest D_mean compared to the HL_2arc (23.96 (20.84, 28.02) Gy) and HL_4arc (24.14 (20.17, 27.53) Gy) plans. Intermediate and low dose regions (40-65% of the prescribed dose) were well fit to the target volume in HL_4arc, compared to the HT and HL_2arc plans. All plans met the dose constraints for the other OARs with sufficient dose margins. The between-group differences in the median NTCP values for the parotid glands and OC were < 3.47% and < 1.7% points, respectively.

CONCLUSIONS

The dosimetric profiles of Halcyon VMAT plans were comparable to that of HT, and HL_4arc showed better dosimetric profiles than HL_2arc for NPCa.

Conjoint analysis of OPRPN and SMR3A protein expression as potential predictive biomarkers for head and neck squamous cell carcinoma after radiotherapy

Increased submaxillary gland androgen‑regulated protein 3A (SMR3A) expression was previously shown to serve as an independent risk factor for oropharyngeal squamous cell carcinoma (OPSCC) and as a surrogate biomarker for active estrogen receptor 2 signaling in radioresistant tumor cells. In the present study, it was aimed to unravel the expression and clinical significance of another member of the opiorphin family, opiorphin prepropeptide (OPRPN), in the radiotherapy for head and neck squamous cell carcinoma (HNSCC). Expression of SMR3A and OPRPN were analyzed for the prior and post fractionated irradiation (4x2 Gy) by double immunofluorescence staining in established HNSCC cell lines as well as by immunohistochemical (IHC) staining in ex vivo tumor tissues. Next, in a retrospective experimental cohort study, primary tumor samples from OPSCC patients (n=96), who received definitive surgery and adjuvant radiotherapy were reviewed, and expression levels of OPRPN protein were detected by IHC. Immunoreactivity scores (IRS) were associated with pathological and clinical risk factors by Chi‑square analysis. Survival analysis was performed by using the Kaplan‑Meier plot, log‑rank test and Cox regression analysis. The expression levels of OPRPN and SMR3A protein were both induced by fractionated irradiation in vitro and ex vivo. In primary tumor samples, IRS of OPRPN was significantly higher than scores of SMR3A expression and positively correlated with expression patterns of SMR3A. SMR3A was confirmed to serve as an unfavorable factor, while OPRPN protein had no significant association with the clinical outcome of patients with OPSCC. A combinational analysis revealed that the subgroup with SMR3A^highOPRPN^low staining pattern had the worst clinical outcome among the various subgroups. Multivariate Cox regression analyses indicated that high expression of SMR3A serves as an independent unfavorable biomarker, while increased expression of OPRPN appears to exert protective function. In summary, the present study indicated that SMR3A and OPRPN serve as potential prognostic markers for HNSCC after radiotherapy.

Delineation uncertainties of tumour volumes on MRI of head and neck cancer patients

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Role of target delineation uncertainties in head and neck cancer patients.

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Knowing contouring variations for MRI allows better adaptation of MRLinac for H&N cancers.

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An interobserver variation for GTV among 8 observers was below 2 mm using MRI.

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Variability between observers might improve using other imaging modalities.

Background

During the last decade, radiotherapy using MR Linac has gone from research to clinical implementation for different cancer locations. For head and neck cancer (HNC), target delineation based only on MR images is not yet standard, and the utilisation of MRI instead of PET/CT in radiotherapy planning is not well established. We aimed to analyse the inter-observer variation (IOV) in delineating GTV (gross tumour volume) on MR images only for patients with HNC.

Material/methods

32 HNC patients from two independent departments were included. Four clinical oncologists from Denmark and four radiation oncologists from Australia had independently contoured primary tumour GTVs (GTV-T) and nodal GTVs (GTV-N) on T2-weighted MR images obtained at the time of treatment planning. Observers were provided with sets of images, delineation guidelines and patient synopsis. Simultaneous truth and performance level estimation (STAPLE) reference volumes were generated for each structure using all observer contours. The IOV was assessed using the DICE Similarity Coefficient (DSC) and mean absolute surface distance (MASD).

Results

32 GTV-Ts and 68 GTV-Ns were contoured per observer. The median MASD for GTV-Ts and GTV-Ns across all patients was 0.17 cm (range 0.08–0.39 cm) and 0.07 cm (range 0.04–0.33 cm), respectively. Median DSC relative to a STAPLE volume for GTV-Ts and GTV-Ns across all patients were 0.73 and 0.76, respectively. A significant correlation was seen between median DSCs and median volumes of GTV-Ts (Spearman correlation coefficient 0.76, p < 0.001) and of GTV-Ns (Spearman correlation coefficient 0.55, p < 0.001).

Conclusion

Contouring GTVs in patients with HNC on MRI showed that the median IOV for GTV-T and GTV-N was below 2 mm, based on observes from two separate radiation departments. However, there are still specific regions in tumours that are difficult to resolve as either malignant tissue or oedema that potentially could be improved by further training in MR-only delineation.

Effect of Autophagy Inhibitors on Radiosensitivity in DNA Repair-Proficient and -Deficient Glioma Cells

Background and Objectives: The development of radioresistance is a fundamental barrier to successful glioblastoma therapy. Autophagy is thought to play a role in facilitating the DNA repair of DNA damage foci in radiation-exposed tumor cells, thus, potentially contributing to their restoration of proliferative capacity and development of resistance in vitro. However, the effect of autophagy inhibitors on DNA damage repair is not fully clear and requires further investigation. Materials and Methods: In this work, we utilized M059K (DNA-PKcs proficient) and M059J (DNA-PKcs deficient) glioma cell lines to investigate the role of autophagy inhibitors in the DNA repair of radiation-induced DNA damage. Cell viability following radiation was determined by trypan blue exclusion in both cell lines. Cell death and autophagy assays were performed to evaluate radiation-induced cell stress responses. DNA damage was measured as based on the intensity of phosphorylated γ-H2AX, a DNA double-stranded breaks (DSBs) marker, in the presence or absence of autophagy inhibitors. Results: The cell viability assay showed that M059J cells were more sensitive to the same dose of radiation (4 Gy) than M059K cells. This observation was accompanied by an elevation in γ-H2AX formation in M059J but not in M059K cells. In addition, the DAPI/TUNEL and Senescence-associated β-galactosidase (SA-β-gal) staining assays did not reveal significant differences in apoptosis and/or senescence induction in response to radiation, respectively, in either cell line. However, acridine orange staining demonstrated clear promotion of acidic vesicular organelles (AVOs) in both cell lines in response to 4 Gy radiation. Moreover, DNA damage marker levels were found to be elevated 72 h post-radiation when autophagy was inhibited by the lysosomotropic agent bafilomycin A1 (BafA1) or the PI3K inhibitor 3-methyl adenine (3-MA) in M059K cells. Conclusions: The extent of the DNA damage response remained high in the DNA-PKcs deficient cells following exposure to radiation, indicating their inability to repair the newly formed DNA-DSBs. On the other hand, radioresistant M059K cells showed more DNA damage response only when autophagy inhibitors were used with radiation, suggesting that the combination of autophagy inhibitors with radiation may interfere with DNA repair efficiency.

Overview and Update on Extracellular Vesicles: Considerations on Exosomes and Their Application in Modern Medicine

In recent years, there has been a rapid growth in the knowledge of cell-secreted extracellular vesicle functions. They are membrane enclosed and loaded with proteins, nucleic acids, lipids, and other biomolecules. After being released into the extracellular environment, some of these vesicles are delivered to recipient cells; consequently, the target cell may undergo physiological or pathological changes. Thus, extracellular vesicles as biological nano-carriers, have a pivotal role in facilitating long-distance intercellular communication. Understanding the mechanisms that mediate this communication process is important not only for basic science but also in medicine. Indeed, extracellular vesicles are currently seen with immense interest in nanomedicine and precision medicine for their potential use in diagnostic, prognostic, and therapeutic applications. This paper aims to summarize the latest advances in the study of the smallest subtype among extracellular vesicles, the exosomes. The article is divided into several sections, focusing on exosomes' nature, characteristics, and commonly used strategies and methodologies for their separation, characterization, and visualization. By searching an extended portion of the relevant literature, this work aims to give a quick outline of advances in exosomes' extensive nanomedical applications. Moreover, considerations that require further investigations before translating them to clinical applications are summarized.

Recurrent Carotid artery blow out in a head & neck patient

Introduction and importance

Carotid artery blowout syndrome is a rare complication of head and neck cancer treatment. It defines a rupture of the carotid artery wall through vessel wall necrosis. This is typically precipitated by radiotherapy, direct tumour invasion, or a combination of these factors. We describe a rare case of three consecutive carotid artery blowouts in a head and neck cancer patient.

Case presentation

A 58-year-old man with a history of T3NO hypopharyngeal squamous cell carcinoma (SCC) treated with chemotherapy and radiation presented with a four-month history of progressive dysphagia and right sided neck pain. Flexible nasendoscopy revealed laryngeal oedema and slough. A panendoscopy and biopsy showed no evidence of tumour recurrence. The patient was discharged and represented with worsening dyspnoea. He subsequently experienced a large volume hemorrhage necessitating ligation of his right external carotid artery. He underwent pharyngolaryngectomy indicated due to the extent of laryngeal radiation necrosis. Thereafter he suffered two additional acute carotid bleeds from his right common carotid necessitating ligation in theatre.

Clinical discussion and conclusion

This case report illustrates the key issues to be considered in patients with locally advanced hypopharyngeal squamous cell carcinoma and subsequent management of acute carotid blowout syndrome, which without prompt management, can be fatal.

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Carotid artery rupture, or blowout, has a high morbidity and mortality.

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Carotid blowout is a rare consequence of head and neck cancer treatment.

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Radiotherapy is the main predisposing risk factor.

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Acute carotid blowout requires prompt resuscitation and bleeding source control.

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Definitive treatment includes endovascular occlusion, stenting or surgical ligation.

Hafnium-Based Metal-Organic Framework Nanoparticles as a Radiosensitizer to Improve Radiotherapy Efficacy in Esophageal Cancer

Radiotherapy is one of the most widely used clinical treatments for tumors, but it faces limitations, such as poor X-ray retention at the tumor site. The use of radiosensitizers containing high Z elements is an effective way to enhance X-ray absorption. Here, we demonstrate a simple one-step method for the synthesis of UiO-66-NH₂(Hf) metal-organic framework nanoparticles for use as radiosensitizers in radiotherapy. The UiO-66-NH₂(Hf) nanoparticles had a diameter of less than 100 nm and were stable in the physiological environment. UiO-66-NH₂(Hf) induced apoptosis by enhancing X-ray absorption, as confirmed by in vitro and in vivo experiments. These characteristics make UiO-66-NH₂(Hf) a promising radiosensitizer for esophageal cancer radiotherapy.

Evaluating Automatic Segmentation for Swallowing-Related Organs for Head and Neck Cancer

Purpose: To evaluate the accuracy of deep-learning-based auto-segmentation of the superior constrictor, middle constrictor, inferior constrictor, and larynx in comparison with a traditional multi-atlas-based method. Methods and Materials: One hundred and five computed tomography image datasets from 83 head and neck cancer patients were retrospectively collected and the superior constrictor, middle constrictor, inferior constrictor, and larynx were analyzed for deep-learning versus multi-atlas-based segmentation. Eighty-three computed tomography images (40 diagnostic computed tomography and 43 planning computed tomography) were used for training the convolutional neural network, and for atlas-based model training. The remaining 22 computed tomography datasets were used for validation of the atlas-based auto-segmentation versus deep-learning-based auto-segmentation contours, both of which were compared with the corresponding manual contours. Quantitative measures included Dice similarity coefficient, recall, precision, Hausdorff distance, 95th percentile of Hausdorff distance, and mean surface distance. Dosimetric differences between the auto-generated contours and manual contours were evaluated. Subjective evaluation was obtained from 3 clinical observers to blindly score the autosegmented structures based on the percentage of slices that require manual modification. Results: The deep-learning-based auto-segmentation versus atlas-based auto-segmentation results were compared for the superior constrictor, middle constrictor, inferior constrictor, and larynx. The mean Dice similarity coefficient values for the 4 structures were 0.67, 0.60, 0.65, and 0.84 for deep-learning-based auto-segmentation, whereas atlas-based auto-segmentation has Dice similarity coefficient results at 0.45, 0.36, 0.50, and 0.70, respectively. The mean 95th percentile of Hausdorff distance (cm) for the 4 structures were 0.41, 0.57, 0.59, and 0.54 for deep-learning-based auto-segmentation, but 0.78, 0.95, 0.96, and 1.23 for atlas-based auto-segmentation results, respectively. Similar mean dose differences were obtained from the 2 sets of autosegmented contours compared to manual contours. The dose–volume discrepancies and the average modification rates were higher with the atlas-based auto-segmentation contours. Conclusion: Swallowing-related structures are more accurately generated with DL-based versus atlas-based segmentation when compared with manual contours.

Head and Neck Squamous Cell Carcinoma: Risk Factors, Molecular Alterations, Immunology and Peptide Vaccines

Head and neck squamous cell carcinoma (HNSCC) arises from the epithelial lining of the oral cavity, hypopharynx, oropharynx, and larynx. There are several potential risk factors that cause the generation of HNSCC, including cigarette smoking, alcohol consumption, betel quid chewing, inadequate nutrition, poor oral hygiene, HPV and Epstein–Barr virus, and Candida albicans infections. HNSCC has causative links to both environmental factors and genetic mutations, with the latter playing a more critical role in cancer progression. These molecular changes to epithelial cells include the inactivation of cancer suppressor genes and proto-oncogenes overexpression, resulting in tumour cell proliferation and distant metastasis. HNSCC patients have impaired dendritic cell (DC) and natural killer (NK) cell functions, increased production of higher immune-suppressive molecules, loss of regulatory T cells and co-stimulatory molecules and major histocompatibility complex (MHC) class Ι molecules, lower number of lymphocyte subsets, and a poor response to antigen-presenting cells. At present, the standard treatment modalities for HNSCC patients include surgery, chemotherapy and radiotherapy, and combinatorial therapy. Despite advances in the development of novel treatment modalities over the last few decades, survival rates of HNSCC patients have not increased. To establish effective immunotherapies, a greater understanding of interactions between the immune system and HNSCC is required, and there is a particular need to develop novel therapeutic options. A therapeutic cancer vaccine has been proposed as a promising method to improve outcome by inducing a powerful adaptive immune response that leads to cancer cell elimination. Compared with other vaccines, peptide cancer vaccines are more robust and specific. In the past few years, there have been remarkable achievements in peptide-based vaccines for HNSCC patients. Here, we summarize the latest molecular alterations in HNSCC, explore the immune response to HNSCC, and discuss the latest developments in peptide-based cancer vaccine strategies. This review highlights areas for valuable future research focusing on peptide-based cancer vaccines.

Temporomandibular disorder as risk factor for radiation-induced trismus in patients with head and neck cancer

Objectives

The aim of this study was to investigate if patients with temporomandibular disorders (TMD) prior to head and neck cancer (HNC) treatment are at higher risk of developing trismus after oncological treatment.

Materials and Methods

Eighty‐three study patients underwent detailed dental examination prior oncological treatment and 6 months after radiotherapy completion, including evaluation of temporomandibular jaw function, palpation of the jaw muscles, and measurement of mouth opening capacity. TMD criteria were based on both clinical examination findings and patient‐reported symptoms. TMD at baseline was used in regression analysis in order to predict restricted mouth opening.

Results

At the 6 months follow‐up more than a third of the patients (35%) were examined with reduced mouth opening of >20% compared to baseline. A majority of the patients had bilateral tenderness of both the temporal and the masseter muscle. At the 6 months follow‐up, 42% of the study patients reported mouth opening problems. About one‐third of the patients suffered from fatigue and stiffness of the jaw as well as pain when mowing the jaw. Two questions from the validated symptom‐specific Gothenburg Trismus Questionnaire were found to be related to a statistically significant increased risk of restricted mouth opening after radiotherapy; “During the last week, have you felt: Pain on moving the jaw?” (OR [95% CI] 5.9 (1.2–29.4) [p = 0.030]) and “During the last week, have you felt pain and tenderness in the muscles of mastication?” (OR [95% CI] 5.90 [1.19–29.40] [p = 0.030]).

Conclusions

TMD is common amongst HNC patients. Patients who suffer from pain in the jaw muscles and pain when moving the jaw before start of treatment are at higher risk of radiation‐induced trismus after 6 months. Clinicians should strive for optimizing the patients pain treatment and oral health before, during, and after radiotherapy.

FOXC2/ADAM12-dependent radiosensitivity of head and neck squamous cell carcinoma cells

BACKGROUND

Radiotherapy greatly benefits patients with tumors, but not all patients show favorable treatment response. This study investigated the impact of forkhead box protein C2 (FOXC2)-mediated a disintegrin and metalloprotease 12 (ADAM12) on the radiosensitivity of head and neck squamous cell carcinoma (HNSCC).

METHODS

After transfection and ionizing radiation, the biological activities of HNSCC cells were assessed. The relationship between ADAM12 and FOXC2 was verified. A xenograft model was used to evaluate the effect of FOXC2 knockdown on HNSCC growth in the context of radiation therapy.

RESULTS

FOXC2 and ADAM12 were upregulated in irradiated CAL-27 and HN4 cells. Knockdown of FOXC2 suppressed the malignant behaviors of CAL-27 and HN4 cells and inhibited the growth of transplanted tumors in nude mice. FOXC2 could bind ADAM12 promoter. Overexpression of ADAM12 reversed the promotion of FOXC2 silencing on the radiosensitivity of HNSCC cells.

CONCLUSIONS

FOXC2 regulates the radiosensitivity of HNSCC by targeting ADAM12.

Late toxicities in locally advanced head and neck squamous cell carcinoma treated with intensity modulated radiation therapy

Purpose

The study aims to report late toxicities in locally advanced head-and-neck squamous cell carcinoma (LAHNSCC) treated with intensity-modulated radiation therapy (IMRT).

Materials and Methods

A retrospective study was conducted on 103 patients of LAHNSCC treated with IMRT. We analyzed the cumulative incidence of late xerostomia, dysphagia, and aspiration at an interval of 6-month, 1-year, 2-year, and 3-year from the start of IMRT.

Results

At a median follow up of 4.2 years (interquartile range, 3.5 to 6 years), the cumulative incidence of grade ≥2 late xerostomia was 5.5%, dysphagia was 6.9%, and aspiration was 11.1%. Logistic regression showed that D_mean of ≥26 Gy to parotids had higher risk of xerostomia (hazard ratio [HR] = 5.19; 95% confidence interval [CI], 1.90–14.22; p = 0.001). Late dysphagia was associated with D_mean of ≥45 Gy to pharyngeal constrictors (PC) (HR = 7; 95% CI, 1.84–26.61; p =0.004), ≥55 Gy to larynx (HR = 3.25; 95% CI, 1.15–9.11; p = 0.025), and adjuvant RT (HR = 5.26; 95% CI, 1.85–14.87; p = 0.002). Aspiration was associated with D_mean of ≥45 Gy to larynx (HR = 6.5; 95% CI, 1.93–21.88; p = 0.003), D_mean of ≥55 Gy to PC (HR = 3.54; 95% CI, 1.25–9.98; p = 0.017), and patients having late dysphagia (HR = 4.37; 95% CI, 1.55–12.31; p = 0.005).

conclusions

IMRT is a feasible radiation delivery technique in LAHNSCC with a decreased late toxicity profile.

Mid-treatment Fluorodeoxyglucose Positron Emission Tomography in Human Papillomavirus-related Oropharyngeal Squamous Cell Carcinoma Treated with Primary Radiotherapy: Nodal Metabolic Response Rate can Predict Treatment Outcomes

AIMS

To evaluate whether biomarkers derived from fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) performed prior to (prePET) and during the third week (interim PET; iPET) of radiotherapy can predict treatment outcomes in human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPC).

MATERIALS AND METHODS

This retrospective analysis included 46 patients with newly diagnosed OPC treated with definitive (chemo)radiation and all patients had confirmed positive HPV status (HPV+OPC) based on p16 immunohistochemistry. The maximum standardised uptake value (SUV_max), metabolic tumour volume (MTV) and total lesional glycolysis (TLG) of primary, index node (node with the highest TLG) and total lymph nodes and their median percentage (≥50%) reductions in iPET were analysed, and correlated with 5-year Kaplan-Meier and multivariable analyses (smoking, T4, N2b-3 and AJCC stage IV), including local failure-free survival, regional failure-free survival, locoregional failure-free survival (LRFFS), distant metastatic failure-free survival (DMFFS), disease-free survival (DFS) and overall survival.

RESULTS

There was no association of outcomes with prePET parameters observed on multivariate analysis. A complete metabolic response of primary tumour was seen in 13 patients; the negative predictive value for local failure was 100%. More than a 50% reduction in total nodal MTV provided the best predictor of outcomes, including LRFFS (88% versus 47.1%, P = 0.006, hazard ratio = 0.153) and DFS (78.2% versus 41.2%, P = 0.01, hazard ratio = 0.234). More than a 50% reduction in index node TLG was inversely related to DMFFS: a better nodal response was associated with a higher incidence of distant metastatic failure (66.7% versus 100%, P = 0.009, hazard ratio = 3.0).

CONCLUSION

The reduction (≥50%) of volumetric nodal metabolic burden can potentially identify a subgroup of HPV+OPC patients at low risk of locoregional failure but inversely at higher risk of distant metastatic failure and may have a role in individualised adaptive radiotherapy and systemic therapy.

Acupuncture for radiation-induced toxicity in head and neck squamous cell carcinoma: a systematic review based on PICO criteria

Purpose

In head and neck squamous cell carcinoma (HNSCC), the potential mitigating effect of complementary medicine interventions such as acupuncture for radiation-induced toxicity is unknown. This study aimed to assess the impact of acupuncture on the incidence and degree of severity of common radiation-induced side effects.

Methods

In accordance with pre-specified PICO criteria, a systematic review was performed. Two electronic databases (Medline and Embase) were searched over a 10-year time frame (01/01/10 to 30/09/20). Patients undergoing a curatively intended, radiation-based treatment for histologically confirmed squamous cell carcinoma of the nasopharynx, oropharynx, larynx, hypopharynx and oral cavity represented the target population of our study. Accurate information on the acupuncture methodology was reported. All included articles were evaluated to identify any potential source of bias

Results

Five papers were included in our qualitative analysis, for a total of 633 subjects. Compliance to per-protocol defined schedule of acupuncture sessions was high, ranging from 82 to 95.9%. Most patients (70.6%) were randomly allocated to receive acupuncture for its potential preventive effect on xerostomia. The large heterogeneity in study settings and clinical outcomes prevented from performing a cumulative quantitative analysis, thus no definitive recommendations can be provided.

Conclusions

Although shown to be feasible and safe, no firm evidence currently supports the use of acupuncture for the routine management of radiation-induced toxicity in HNSCC.

Marathi Translation and Linguistic Validation of an Updated European Organization for Research and Treatment of Cancer Quality of Life Module for Head and Neck

Aim  This study was aimed to translate an updated European Organization for Research and Treatment of Cancer (EORTC) quality of life module for head and neck (EORTC QLQ-H&N43) in grammatically and conceptually acceptable Marathi language and its linguistic validation.

Materials and Methods  Approval was obtained from the Institutional Ethics Committee. The permission for translation was obtained from the EORTC translation unit (TU). The EORTC guidelines for the translation were followed to form a translation for pilot testing which was administered to 10 Marathi speaking head and neck squamous cell cancer (HNSCC) patients who gave informed written consent for the participation in the study. Patients were interviewed personally. The final Marathi translation was prepared and sent to EORTC TU for approval. Statistical analysis was performed using SYSTAT version 12 by Cranes software, Bengaluru, Karnataka, India.

Results  After getting permission, the translation files were received from EORTC TU, including Marathi EORTC QLQ-H&N35 for reference. Two forward translations, reconciled translation, back translations, first interim translation, translation for proof editing, and second interim translation (SIT) were prepared. This SIT was pilot tested in 10 Marathi-speaking HNSCC patients. Each patient was interviewed regarding difficulty in answering, confusing or offensive word, and reframing sentence. The questionnaire was well understood by patients reflecting its linguistic validity. After incorporating the changes as per the patient’s interview, updated translation was prepared and sent to EORTC TU which was accepted and approved by EORTC. The psychometric analysis of pilot testing showed that the questionnaire is acceptable.

Conclusion  Marathi translation of EORTC QLQ-H&N43 is well accepted and understandable. It can be used for future studies.

Interobserver variability in organ at risk delineation in head and neck cancer

Background

In radiotherapy inaccuracy in organ at risk (OAR) delineation can impact treatment plan optimisation and treatment plan evaluation. Brouwer et al. showed significant interobserver variability (IOV) in OAR delineation in head and neck cancer (HNC) and published international consensus guidelines (ICG) for OAR delineation in 2015. The aim of our study was to evaluate IOV in the presence of these guidelines.

Methods

HNC radiation oncologists (RO) from each Belgian radiotherapy centre were invited to complete a survey and submit contours for 5 HNC cases. Reference contours (OARref) were obtained by a clinically validated artificial intelligence-tool trained using ICG. Dice similarity coefficients (DSC), mean surface distance (MSD) and 95% Hausdorff distances (HD95) were used for comparison.

Results

Fourteen of twenty-two RO (64%) completed the survey and submitted delineations. Thirteen (93%) confirmed the use of delineation guidelines, of which six (43%) used the ICG. The OARs whose delineations agreed best with the OARref were mandible [median DSC 0.9, range (0.8–0.9); median MSD 1.1 mm, range (0.8–8.3), median HD95 3.4 mm, range (1.5–38.7)], brainstem [median DSC 0.9 (0.6–0.9); median MSD 1.5 mm (1.1–4.0), median HD95 4.0 mm (2.3–15.0)], submandibular glands [median DSC 0.8 (0.5–0.9); median MSD 1.2 mm (0.9–2.5), median HD95 3.1 mm (1.8–12.2)] and parotids [median DSC 0.9 (0.6–0.9); median MSD 1.9 mm (1.2–4.2), median HD95 5.1 mm (3.1–19.2)]. Oral cavity, cochleas, PCMs, supraglottic larynx and glottic area showed more variation. RO who used the consensus guidelines showed significantly less IOV (p = 0.008).

Conclusions

Although ICG for delineation of OARs in HNC exist, they are only implemented by about half of RO participating in this study, which partly explains the delineation variability. However, this study highlights that guidelines alone do not suffice to eliminate IOV and that more effort needs to be done to accomplish further treatment standardisation, for example with artificial intelligence.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s13014-020-01677-2.

Awareness of the risk of radiation-related caries in patients with head and neck cancer: A survey of physicians, dentists, and patients

OBJECTIVES

Radiation-related caries (RRC) is one of the most aggressive complications of radiotherapy (RT) in survivors of head and neck cancer (HNC). Lack of RRC awareness may contribute to the occurrence of this oral cavity complication. RRC may be considered a "forgotten oral complication" by patients with HNC, oncologists, and dentists. The present study aimed to assess the level of awareness of RRC among physicians, dentists, and patients.

STUDY DESIGN

Physicians (group 1, G1), dentists (group 2, G2), and patients with HNC undergoing RT (group 3, G3) answered questionnaires concerning their awareness of RRC. Physicians (G1) were divided into group 1A (oncological experience) and group 1B (general physicians/other specialties). Dentists (G2) were divided into group 2A (oncological experience) and group 2B (general dentists/other specialties). Personalized questionnaires were designed for each group.

RESULTS

Recruitment was as follows: physicians (n = 124): 1A (n = 64), 1B (n = 60); dentists: (n = 280), 2A (n = 160), 2B (n = 120). In addition, 58 patients answered the questionnaire. In terms of RRC awareness, 46.77% of physicians, 81.78% of dentists, and 24.13% of patients had some knowledge of the problem.

CONCLUSION

Patient awareness of RRC was poor. The heterogeneity of answers among physicians and dentists suggests an opportunity to improve patient education and prevention of this serious oral complication of RT.

Radiation therapy in head and neck cancer

This review summarizes the beginning of radiotherapy, techniques of modern radiation therapy with different types, toxicities induced by radiotherapy and their management. Head and neck radiation therapy is still improving for the better management and control of the cancer and induced radiotherapy toxicities.

Improving the therapeutic ratio of radiotherapy against radioresistant cancers: Leveraging on novel artificial intelligence-based approaches for drug combination discovery

Despite numerous advances in cancer radiotherapy, tumor radioresistance remain one of the major challenges limiting treatment efficacy of radiotherapy. Conventional strategies to overcome radioresistance involve understanding the underpinning molecular mechanisms, and subsequently using combinatorial treatment strategies involving radiation and targeted drug combinations against these radioresistant tumors. These strategies exploit and target the molecular fingerprint and vulnerability of the radioresistant clones to achieve improved efficacy in tumor eradication. However, conventional drug-screening approaches for the discovery of new drug combinations have been proven to be inefficient, limited and laborious. With the increasing availability of computational resources in recent years, novel approaches such as Quadratic Phenotypic Optimization Platform (QPOP), CURATE.AI and Drug Combination and Prediction and Testing (DCPT) platform have emerged to aid in drug combination discovery and the longitudinally optimized modulation of combination therapy dosing. These platforms could overcome the limitations of conventional screening approaches, thereby facilitating the discovery of more optimal drug combinations to improve the therapeutic ratio of combinatorial treatment. The use of better and more accurate models and methods with rapid turnover can thus facilitate a rapid translation in the clinic, hence, resulting in a better patient outcome. Here, we reviewed the clinical observations, molecular mechanisms and proposed treatment strategies for tumor radioresistance and discussed how novel approaches may be applied to enhance drug combination discovery, with the aim to further improve the therapeutic ratio and treatment efficacy of radiotherapy against radioresistant cancers.

A comparison of methods for fully automatic segmentation of tumors and involved nodes in PET/CT of head and neck cancers

Target volume delineation is a vital but time-consuming and challenging part of radiotherapy, where the goal is to deliver sufficient dose to the target while reducing risks of side effects. For head and neck cancer (HNC) this is complicated by the complex anatomy of the head and neck region and the proximity of target volumes to organs at risk. The purpose of this study was to compare and evaluate conventional PET thresholding methods, six classical machine learning algorithms and a 2D U-Net convolutional neural network (CNN) for automatic gross tumor volume (GTV) segmentation of HNC in PET/CT images. For the latter two approaches the impact of single versus multimodality input on segmentation quality was also assessed. 197 patients were included in the study. The cohort was split into training and test sets (157 and 40 patients, respectively). Five-fold cross-validation was used on the training set for model comparison and selection. Manual GTV delineations represented the ground truth. Tresholding, classical machine learning and CNN segmentation models were ranked separately according to the cross-validation Sørensen-Dice similarity coefficient (Dice). PET thresholding gave a maximum mean Dice of 0.62, whereas classical machine learning resulted in maximum mean Dice scores of 0.24 (CT) and 0.66 (PET; PET/CT). CNN models obtained maximum mean Dice scores of 0.66 (CT), 0.68 (PET) and 0.74 (PET/CT). The difference in cross-validation Dice between multimodality PET/CT and single modality CNN models was significant (p ≤ 0.0001). The top-ranked PET/CT-based CNN model outperformed the best-performing thresholding and classical machine learning models, giving significantly better segmentations in terms of cross-validation and test set Dice, true positive rate, positive predictive value and surface distance-based metrics (p ≤ 0.0001). Thus, deep learning based on multimodality PET/CT input resulted in superior target coverage and less inclusion of surrounding normal tissue.

Diffusion weighted imaging in submandibular gland sparing helical tomotherapy for nasopharyngeal carcinoma

PURPOSE

To verify clinical significance of submandibular gland (SMG)-sparing during helical tomotherapy (HT) for nasopharyngeal carcinoma (NPC) from the perspective of imaging by using diffusion weighted imaging (DWI).

MATERIALS AND METHODS

In this prospective study, 60 NPC patients scheduled for radical SMG-sparing HT were enrolled. All patients underwent DWI examinations prior to HT (pre-HT) and 1, 3, 6, 9, 12 months post HT. Mean apparent diffusion coefficient (ADC) values of bilateral parotid glands (PGs) and submandibular glands (SMGs) were measured. Differences of ADC and changes of ADC pre and pro HT (ΔADC) among SMG-spared, SMG-unspared and PGs were compared and the associations betweenΔADC and variations of patient-rated xerostomia questionnaire summary scores (XQ-sum) were further tested.

RESULTS

ADC_post-HT and ΔADC_post-HT of SMG-spared were both much lower than of SMG-unspared and a strong dose-response relationship was detected between mean radiation dose and ΔADC of SMGs. Dynamic change trends of PGs, SMG-spared and SMG-unspared were similar, with initial increase at 1 m-post-HT followed by little change at 3 m-post-HT and then gradual decrease over time. But for SMG-unspared, there was no obvious change of ADC from 6 m-post-HT to 12 m-post-HT. The dynamic change trend of XQ-sum was nearly in line with that of ADC on the whole. And a positive correlation between mean ΔADC_1m-post-HT of bilateral SMGs and variation of XQ-sum_1m-post-HT in patients with bSMG-unspared were found (r = 0.693, P < 0.001). Multivariate stepwise regression analysis showed that whether spared SMG or not was the only independent predictor correlated to XQ-sum_post-HT at each follow-up timepoint.

CONCLUSION

SMG-sparing technique could significantly improve subjective xerostomia post HT in NPC patients from the perspective of imaging.

Risk of ischaemic cerebrovascular events in head and neck cancer patients is associated with carotid artery radiation dose

BACKGROUND AND PURPOSE

Radiotherapy in the head and neck area may cause vascular damage to the carotid arteries, increasing the risk of anterior circulation ischaemic cerebrovascular events (ICVEs). However, limited data exists on the relationship between radiation dose to the carotid arteries and risk of ICVE. The purpose of this study was therefore to determine the relationship between radiation dose to the carotid arteries and anterior circulation ICVE risk.

MATERIALS AND METHODS

A retrospective analysis of a prospective study cohort of 750 head and neck cancer patients treated with definitive (chemo)radiotherapy was performed. Carotid arteries were delineated, and dose-volume parameters of the treatment plans were calculated. ICVEs were scored prospectively and checked retrospectively by analysing all patient records. Cox proportional hazards analysis was performed to analyse the dose-effect relationships.

RESULTS

The median follow-up period was 3.4 years, 27 patients experienced an ICVE and the 5-year cumulative risk was 4.6%. ICVE risk was significantly associated with dose to the carotid arteries. Multivariable analysis showed that the absolute volume (cm³) of the carotid arteries that received at least a radiation dose of 10 Gy was the most important prognostic factor for ICVE (HR = 1.11, AUC = 0.68, p < 0.001).

CONCLUSION

This is the first large prospective cohort study that demonstrates an independent dose-effect relationship between radiation dose to the carotid arteries and the risk of ICVE. These findings may be used to identify patients at risk for ICVE after radiotherapy who may benefit from primary or secondary preventive measures.

Prospects and challenges of extracellular vesicle-based drug delivery system: considering cell source

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are nanosized membrane vesicles derived from most cell types. Carrying diverse biomolecules from their parent cells, EVs are important mediators of intercellular communication and thus play significant roles in physiological and pathological processes. Owing to their natural biogenesis process, EVs are generated with high biocompatibility, enhanced stability, and limited immunogenicity, which provide multiple advantages as drug delivery systems (DDSs) over traditional synthetic delivery vehicles. EVs have been reported to be used for the delivery of siRNAs, miRNAs, protein, small molecule drugs, nanoparticles, and CRISPR/Cas9 in the treatment of various diseases. As a natural drug delivery vectors, EVs can penetrate into the tissues and be bioengineered to enhance the targetability. Although EVs' characteristics make them ideal for drug delivery, EV-based drug delivery remains challenging, due to lack of standardized isolation and purification methods, limited drug loading efficiency, and insufficient clinical grade production. In this review, we summarized the current knowledge on the application of EVs as DDS from the perspective of different cell origin and weighted the advantages and bottlenecks of EV-based DDS.

Individualized quality of life benefit and cost-effectiveness estimates of proton therapy for patients with oropharyngeal cancer

Background

Proton therapy is a promising advancement in radiation oncology especially in terms of reducing normal tissue toxicity, although it is currently expensive and of limited availability. Here we estimated the individual quality of life benefit and cost-effectiveness of proton therapy in patients with oropharyngeal cancer treated with definitive radiation therapy (RT), as a decision-making tool for treatment individualization.

Methods and materials

Normal tissue complication probability models were used to estimate the risk of dysphagia, esophagitis, hypothyroidism, xerostomia and oral mucositis for 33 patients, comparing delivered photon intensity-modulated RT (IMRT) plans to intensity-modulated proton therapy (IMPT) plans. Quality-adjusted life years (QALYs) lost were calculated for each complication while accounting for patient-specific conditional survival probability and assigning quality-adjustment factors based on complication severity. Cost-effectiveness was modeled based on upfront costs of IMPT and IMRT, and the cost of acute and/or long-term management of treatment complications. Uncertainties in all model parameters and sensitivity analyses were included through Monte Carlo sampling.

Results

The incremental cost-effectiveness ratios (ICERs) showed considerable variability in the cost of QALYs spared between patients, with median $361,405/QALY for all patients, varying from $54,477/QALY to $1,508,845/QALY between individual patients. Proton therapy was more likely to be cost-effective for patients with p16-positive tumors ($234,201/QALY), compared to p16-negative tumors ($516,297/QALY). For patients with p16-positive tumors treated with comprehensive nodal irradiation, proton therapy is estimated to be cost-effective in ≥ 50% of sampled cases for 8/9 patients at $500,000/QALY, compared to 6/24 patients who either have p16-negative tumors or receive unilateral neck irradiation.

Conclusions

Proton therapy cost-effectiveness varies greatly among oropharyngeal cancer patients, and highlights the importance of individualized decision-making. Although the upfront cost, societal willingness to pay and healthcare administration can vary greatly among different countries, identifying patients for whom proton therapy will have the greatest benefit can optimize resource allocation and inform prospective clinical trial design.

Pluripotent Stem Cell-Derived Mesenchymal Stem Cells Show Comparable Functionality to Their Autologous Origin

A multimodal therapeutic approach involving radiotherapy is required when treating head and neck squamous cell carcinoma. However, radiotherapy is restricted due to its high risk for damages to the surrounding healthy tissue of the treated area. Tissue regeneration and wound healing is promoted by the survival and regenerative capacities of tissue-resident or invading stem cells. Mesenchymal stem cells (MSCs) exhibit a promising therapeutic potential in the field of cell-based tissue engineering and regenerative medicine due to their immunomodulatory properties and differentiation capacity. However, the generation of MSCs for therapeutic applications is still a major challenge. We aimed to produce highly homogeneous induced pluripotent stem cell-derived mesenchymal stem cells (iP-MSCs) in an autologous manner from initially isolated human mucosa mesenchymal stem cells (mMSCs) of the upper respiratory tract. Therefore, mMSCs were reprogrammed into induced pluripotent stem cells (iPSCs) by non-integrative chromosomal technologies and differentiated into corresponding iP-MSCs. We demonstrated that mMSCs and iP-MSCs show similar cell characteristics in terms of morphology, clonogenic potential, differentiation, and surface phenotype. Moreover, iP-MSCs demonstrated related immunosuppressive capacity as mMSCs including the secretion of cytokines, and T cell inhibition. Therefore, generating iP-MSCs in an autologous manner may be a novel personalized treatment option in regenerative medicine.

Functional proteomic analysis reveals roles for PKCδ in regulation of cell survival and cell death: Implications for cancer pathogenesis and therapy

Protein Kinase C-δ (PKCδ), regulates a broad group of biological functions and disease processes, including well-defined roles in immune function, cell survival and apoptosis. PKCδ primarily regulates apoptosis in normal tissues and non-transformed cells, and genetic disruption of the PRKCD gene in mice is protective in many diseases and tissue damage models. However pro-survival/pro-proliferative functions have also been described in some transformed cells and in mouse models of cancer. Recent evidence suggests that the contribution of PKCδ to specific cancers may depend in part on the oncogenic context of the tumor, consistent with its paradoxical role in cell survival and cell death. Here we will discuss what is currently known about biological functions of PKCδ and potential paradigms for PKCδ function in cancer. To further understand mechanisms of regulation by PKCδ, and to gain insight into the plasticity of PKCδ signaling, we have used functional proteomics to identify pathways that are dependent on PKCδ. Understanding how these distinct functions of PKCδ are regulated will be critical for the logical design of therapeutics to target this pathway.