Advances in Radiotherapy for Head and Neck Cancer

Recommendations for radiotherapy quality assurance in clinical trials

Robust quality assurance (QA) of clinical trials in radiotherapy (RT) is paramount for minimising uncertainties in treatment delivery, thereby strengthening the statistical power of the study and increasing the likelihood of accurately answering the research question. As RT techniques evolve and become more complex, establishing an appropriate QA program for a specific clinical trial becomes increasingly challenging, highlighting the importance of clear and standardised recommendations. This study provide such recommendations for Principal Investigators (PIs) to consider when planning and conducting RT Quality Assurance (RTQA) for clinical trials. They arise from experiences with RTQA in the clinical trials conducted in the Danish Multidisciplinary Cancer Groups (DMCGs). The recommendations include a checklist to guide PIs in developing an effective RTQA program.

Comparative dosimetric assessment of combined treatment modalities in cervical cancer radiotherapy for optimal organ protection

External radiotherapy combined with internal radiotherapy in cervical cancer can provide a boost to the target volume to increase tumour control. At the same time internal radiotherapy protects neighboring organs. The aim of the present study was to dosimetrically compare three external beam radiotherapy techniques each combined with internal radiotherapy to evaluate the combination that offers the best organ protection. Treatment plans of 20 cervical cancer patients were created for external (including three-dimensional conformal radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT)) as well as brachytherapy. The prescribed dose was 50 Gy in 25 fractions for external and 21 Gy in three fractions for internal radiotherapy. The following organs at risk (OARs) were evaluated: bladder, rectum, sigmoid and bowel bag. The study analyzed the results of different treatment combinations in terms of dosimetric values for various parameters. The D90 for the clinical target volume was around 120 Gy, with the highest value seen in 3D-CRT + BT (brachytherapy) combination at 120.59 Gy. For the bladder, the D2cc remained below the recommended threshold of 90 Gy, with the lowest value obtained for the BT + IMRT combination at 79.2 Gy. For the rectum, both D2cc and D1cc remained below the recommended threshold of 75 Gy for both parameters. All techniques fell below the recommended dose of 75 Gy for the sigmoid. For the intestine, there were statistically significant differences between BT + IMRT and BT + 3D-CRT. The VMAT technique showed superiority over IMRT in tumour volume coverage and several organ-at-risk parameters. Generally, intensity-modulated techniques showed dosimetric advantage over the traditional 3D technique in cervical cancer. In addition to providing better compliance and homogeneity, they provided superior protection for organs at risk, especially for bowel bag. It is concluded that the BT + IMRT technique provided the best protection for organs at risk based on the lowest OAR dosimetric values, especially for the intestine.

Radiation induced dermatitis by increasing triglyceride levels to induce autophagy and inhibit the PI3K/Akt/mTOR signaling pathway

BACKGROUND

Radiodermatitis (RD) is the primary acute adverse effect experienced by patients receiving radiotherapy (RT) for head and neck cancer (HNC). This study aimed to investigate the correlation between triglyceride (TG) levels and the severity of RD, as well as the underlying mechanisms involved.

METHODS

Data were collected from 248 patients with locally advanced HNC treated with intensity-modulated radiation therapy (IMRT). Clinical characteristics and blood profiles prior to RT were collected. After RT, RD severity was assessed. A binary logistic regression analysis was used to determine risk factors. Mouse models of RD were established by administering radiating at a dose of 9 Gy over two consecutive days. TG levels in the mice and cells were quantified using an automatic biochemical analyzer and a TG assay kit, respectively. Cell viability was detected by the Cell Counting Kit-8 (CCK-8) assay, while apoptotic cell percentages were measured via flow cytometry. Western blotting assay was used to analyze the protein levels in the cells of interest.

RESULTS

The TG level was the sole independent risk factor for grade 3 or higher (grade 3+) RD. Radiation was found to increase the TG content in both mouse blood and skin cells. Skin cells with high TG contents presented more severe radiation-induced damage when the radiation dose administered was 9 Gy over two consecutive days. The administration of 200 µmol/L palmitic acid (PA) or 2 Gy radiation independently did not affect HaCaT cell proliferation or apoptosis rates. Their combination was shown to induce skin cell injury. Mechanistically, autophagy was excessively activated. Furthermore, the protein concentrations of phospho-PI3K, phospho-Akt, and phospho-mTOR were notably decreased.

CONCLUSIONS

TGs are crucially involved in the development of RD. Increased TG levels after radiation treatment suppress the PI3K/Akt/mTOR pathway, induce autophagy, and exacerbate RD.

The Emerging Role of Nanoparticles Combined with Either Radiotherapy or Hyperthermia in Head and Neck Cancer: A Current Review

Head and neck cancer (HNC) includes various malignancies and represents the seventh most common cancer worldwide. The early diagnosis of HNC results in a 70-90% five-year survival rate, which declines with locally advanced stages of disease. Current care employs a multimodal strategy encompassing surgery, radiation therapy (RT), chemotherapy, and immunotherapy, while treatment options vary according to the stage, tumor features, and patient characteristics. About 75% of patients with HNC will benefit from RT, either as a primary treatment or as adjuvant therapy following surgical resection. Technological improvements in RT, such as intensity-modulated RT (IMRT) and image-guided RT (IGRT), have enhanced tumor targeting and minimized adjacent healthy tissue irradiation while also expanding RT to the recurrent or metastatic setting. Innovative therapeutic strategies for HNC integrate RT with immunotherapy, gene therapy, molecular targeted therapy, photodynamic therapy, photothermal therapy, and nanoparticles (NPs), with the objective of optimizing tumor control while reducing damage to normal tissues. NPs are emerging as possible radiosensitizers in HNC treatment, enhancing the efficacy of RT, chemotherapy, and immunotherapy. In vivo and in vitro studies on the irradiation of tumors containing gold (Au), gadolinium (Gd), and hafnium oxide (HfO2) NPs show promising results in enhancing tumor destruction and survival rates, indicating their potential for clinical application. Hyperthermia, investigated as an adjunct treatment, potentially improves outcomes when combined with RT or chemotherapy, with advancements in nanotechnology renewing interest in this approach in HNC. At present, NBTXR3 is the sole NP that is being investigated in clinical trials for the enhancement of HNC RT.

Dosimetric Comparison of Noncoplanar VMAT Without Rotating the Patient Couch Versus Conventional Coplanar/Noncoplanar VMAT for Head and Neck Cancer: First Report of Dynamic Swing Arc

Purpose

This retrospective planning study aimed to verify the usefulness of a clinically available method, dynamic swing arc (DSA), a noncoplanar volumetric modulated arc therapy (VMAT) technique, of the new accelerator OXRAY for head and neck squamous cell carcinoma (HNSCC). We performed dosimetric comparisons between DSA and conventional coplanar/noncoplanar VMAT (C-VMAT/NC-VMAT) plans for HNSCC.

Methods and Materials

We selected 32 patients with oropharyngeal and hypopharyngeal cancer treated with C-VMAT at National Cancer Center Hospital East between September 2018 and July 2023. DSA and C/NC-VMAT plans were generated using OXRAY and TrueBeam, respectively. DSA employed noncoplanar 2-arc beams with an O-ring gantry swing, whereas C-VMAT and NC-VMAT used coplanar and noncoplanar 2-arc beams, respectively. Dosimetric parameters, normal tissue complication probability, and delivery times were compared pairwise using the Wilcoxon signed-rank test with Bonferroni correction.

Results

For high-risk planning target volume (PTV), D98 values in NC-VMAT plans were closest to the prescribed dose, significantly differing from C-VMAT and DSA plans. DSA plans showed significantly better median conformity and homogeneity indices (0.97 and 7.33, respectively) compared to C-VMAT (0.95 and 8.36) and NC-VMAT (0.96 and 7.96) plans. DSA plans significantly reduced the mean ipsilateral/contralateral parotid gland dose by 5.78/6.93 and 2.88/1.56 Gy (median) compared to C-VMAT and NC-VMAT. NC-VMAT and DSA plans significantly decreased the mean oral cavity dose by 2.16 and 3.22 Gy (median) compared to C-VMAT. DSA plans had the lowest median normal tissue complication for xerostomia with significant differences, followed by NC-VMAT and C-VMAT. The delivery time for DSA plans was longer than VMAT (151 seconds vs 124 seconds), but shorter than NC-VMAT.

Conclusions

DSA plans using OXRAY for HNSCC maintained PTV coverage while reducing parotid gland and oral cavity mean doses compared to coplanar VMAT plans, although delivery times increased. DSA plans reduced parotid gland doses and delivery times compared to noncoplanar VMAT plans.

Cuproptosis-Inducing Functional Nanocomposites for Enhanced and Synergistic Cancer Radiotherapy

Radiotherapy is crucial in local cancer management and needs advancements. Tumor cells elevate intracellular copper levels to promote growth and resist radiation; thus, targeted copper delivery to mitochondria could enhance radiotherapy by inducing cuproptosis in tumor cells. In this study, we engineered a multifunctional nanoliposome complex, termed Lipo-Ele@CuO2, which encapsulates both copper peroxide (CuO2) and the copper chelator elesclomol, which can delivery Cu ions to the mitochondria. The Lipo-Ele@CuO2 complex induces mitochondria-mediated cuproptosis in tumor cells and synergistically enhances the efficacy of radiotherapy. CuO2 acts as a copper donor and exhibits inherent sensitivity to acidic environments. Additionally, it depletes intracellular glutathione, thereby sensitizing cells to cuproptosis. Leveraging its pH-responsive properties in the acidic tumor microenvironment, the Lipo-Ele@CuO2 facilitate the controlled release of elesclomol, efficiently delivering copper ions to mitochondria at tumor sites. The combined in vitro and in vivo studies demonstrate that Lipo-Ele@CuO2-based therapy significantly improves antitumor efficacy and exhibits excellent safety profiles, effectively inducing cuproptosis in tumor cells and boosting the effectiveness of radiotherapy. Furthermore, metabolomic and transcriptomic analyses reveal that this combination therapy precipitates significant alterations in tumor energy metabolism, notably repressing genes related to iron-sulfur cluster assembly and glycolysis, thereby confirming the induction of cuproptosis. This therapeutic strategy provides a viable approach for addressing clinical radiotherapy resistance and demonstrates significant translational potential.

Effectiveness of Early Oral Nutritional Supplementation in Preventing Weight Loss in Head and Neck Cancer Patients Undergoing Postoperative Radiotherapy or Chemoradiotherapy: A Prospective Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Patients with locally advanced head and neck squamous cell carcinoma (HNSCC) typically undergo surgery followed by postoperative radiotherapy/chemoradiotherpy. Nutritional issues often arise during treatment, potentially affecting outcomes. This study aimed to investigate whether early initiation of oral nutritional supplements (ONS) would prevent weight loss in HNSCC patients undergoing postoperative radiotherapy/chemoradiotherapy compared to conventional nutritional intervention.

SUBJECTS AND METHODS

Sixty-five surgically treated HNSCC patients were randomized to early nutritional intervention (ENI) or conventional nutritional intervention (CNI) groups. The ENI group started ONS two weeks before radiotherapy, while the CNI group initiated ONS based on dietitian's advice when dietary intake was insufficient. Primary endpoint was body weight change from baseline to two weeks post-radiotherapy. Secondary endpoints included nutritional status, body composition, adverse events, quality of life, and survival.

RESULTS

Patients in the ENI group experienced less pronounced weight loss compared to those in the CNI group. Lower serum prealbumin levels were observed in the CNI group during radiotherapy, while no significant between-group differences existed in other nutritional parameters, QoL, or survival.

CONCLUSION

Early ONS intervention effectively prevented significant weight loss in HNSCC patients undergoing postoperative radiotherapy/chemoradiotherapy. Our findings strongly support prioritizing and integrating early nutritional support with ONS into routine care for this patient population, given its clear benefits in improving nutritional outcomes during treatment.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov. NCT03545490.

Risk Stratification for Trial Enrichment Considering Loco-Regional Failure in Head and Neck Cancer: UICC8 Versus Purpose-Built Failure-Type Specific Risk Prediction Model

BACKGROUND

A previously published failure-type specific risk model showed good performance in the original cohort.

AIM

to validate the model and separate patients with high- and low-risk loco-regional failure (LRF).

GOAL

to identify patients potentially suitable for treatment intensification trials.

METHODS

Validation data: 756 patients from two institutions (different countries). Predictive performance was evaluated by Brier scores and AUCs. Discriminatory performance was compared to Union for International Cancer Control (UICC) staging (versions 7 and 8).

RESULTS

The model's 3-year AUC for LRF was 65%, significantly better than UICC7 staging, but no significant difference to UICC8. Model-based risk stratification and UICC8 both identified high-risk patient groups with 3-year LRF ≈30%. The population mean was 18%.

CONCLUSIONS

The model performed well on a group level. UICC8 staging performed equally well. Although developed for the endpoint of OS, an improvement from UICC version 7 to version 8 was evident also for the prediction of LRF.

Carotid artery stenosis and ischemic cerebrovascular events after radiotherapy in patients with head and neck cancer

Radiotherapy is the main treatment for patients with head and neck cancer (HNC) and is associated with an increased risk of ischemic cerebrovascular events (ICVE). The purpose of this cross-sectional study was to determine the incidence of ICVE and carotid artery stenosis (CAS) in patients with HNC who receive radiotherapy and the risk factors for CAS. We enrolled 907 patients with HNC who underwent radiotherapy between February 2011 and June 2022 and obtained information on their clinical and tumor characteristics and their treatment from the clinical records. Data on risk factors for atherosclerosis, medications used, and radiotherapy were also collected. The patients were followed through to the end of 2023 unless they died or were lost to follow-up. The overall incidence of ICVE was 1.98%, with a cumulative incidence of 1.65% over 5 years. In patients who did not have a preexisting carotid artery lesion, the cumulative incidence of significant CAS was 1.3% at 12 months, 2.2% at 24 months, and 2.5% at 36 months post-radiotherapy. The most important risk factors for new CAS were age >65 years (aHR = 2.60, p = 0.008, 95% confidence Interval: 1.28-5.30), laryngeal cancer (aHR = 2.36, p<0.017, 95% confidence Interval: 1.01-5.55), and total plaque score (aHR = 1.38, p<0.001, 95% confidence Interval: 1.23-1.56). There was a significant increase in stenosis, plaque score, and wall thickness in all areas in the carotid artery (p<0.001). The incidence of ICVE and the cumulative incidence of CAS was found to be lower in the Thai population than in other populations. The main risk factors for new CAS were age >65 years, laryngeal cancer, and total plaque score. Changes in the carotid artery were detected early and affected all areas in the artery. Patients with HNC treated by radiotherapy should be assessed for risk factors for CAS and undergo vascular surveillance during follow-up.

Compressed Sensing-Based Cine-MRI for Location of Dysphagia and Swallowing Function assessment in Patients with Head and Neck Cancer: A Comparative Study

Cine magnetic resonance imaging (Cine-MRI) may evaluate the swallowing function and locations of patients with dysphagia, which requires very fast imaging speed. Compressed sensing is a technique that allows for faster MRI imaging by sampling fewer data points and reconstructing the image via optimization techniques, crucial for capturing the rapid movements involved in swallowing. This study aimed to analyze swallowing function and locations in patients with head and neck cancer and healthy individuals using Cine-MRI based on compressed sensing. This comparative study enrolled 36 patients with dysphagia and 10 healthy controls at the Department of Radiology, Yunnan Cancer Hospital between June 2020 and January 2021. Significant correlations were found between primary tumor location and Cine-MRI parameters, and between swallowing function and Cine-MRI parameters. The areas under the receiver operating characteristic curve for the combined Cine-MRI-related parameters in predicting mild and severe dysphagia were 0.806 (95% CI: 0.662-0.949). Cine-MRI with compressed sensing may identify swallowing function and abnormal stages of the physiologic swallowing process in patients with dysphagia after treatment.

Changing Landscape of Head and Neck Squamous Cell Carcinoma and Nasopharyngeal Carcinoma Treatment and Survival Trends in Thailand: A 13-Year Multicenter Retrospective Study of Patients

PURPOSE

The incidence and survival rates of head and neck squamous cell carcinoma (HNSCC) and nasopharyngeal carcinoma (NPC) vary globally, influenced by factors such as ethnicity, lifestyle, and health care systems.

METHODS

A retrospective analysis was conducted on patients with HNSCC treated between 2008 and 2020 in four major Thai academic cancer centers, using a multidisciplinary multicenter database. The study focused on the evolution of patient characteristics, survival changes, and treatment landscape alterations over time.

RESULTS

Among 6,319 patients, the most common primary sites were nasopharynx (33%), oral cavity (23%), oropharynx (17%), larynx (15%), and hypopharynx (8%). An increase in human papillomavirus-related oropharyngeal carcinoma was noted, from 13% in 2008 to 42% in 2019-2020. The majority of patients presented with locally advanced (LA) stages (IVa/b: 50%, III: 26%). Chemoradiotherapy (54%) and surgery (24%) were the main treatments, with cisplatin (79%) being most commonly used in chemoradiation. Overall survival (OS) improved annually across all subsites, correlating with an increase in intensity-modulated radiotherapy (IMRT) use, from 25% in 2008 to 90% in 2019-2020. The median follow-up duration was 4.59 years, with a minimum of 2.75 years. Patients treated with IMRT had significantly longer OS compared with those treated with non-IMRT techniques, in both NPC and non-NPC HNSCC (P < .001).

CONCLUSION

To our knowledge, this is the largest study in Thailand that demonstrates increasing survival outcomes in patients with HNSCC and NPC, despite commonly presenting with LA stages. The increasing use of IMRT may be contributing to improved survival outcomes in both patients with NPC and non-NPC HNSCC patients.

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.

Correlation of degree of acute radiation dermatitis (RD) with skin dose distribution in head and neck squamous cell carcinoma patients treated with definitive concurrent chemoradiation

Background

Radiation dermatitis (RD) or skin toxicity is one of the most common acute side effects of radiation in head and neck cancer patients. This study aims to correlate the pattern of volumetric-modulated arc therapy (VMAT) dose distribution to the skin with the grades of RD.

Materials and methods

80 plans of histopathologically proven squamous cell carcinoma head and neck patients already treated with definitive concurrent chemoradiation [66-70 Gy in 33-35# or 66 Gy in 30# in simultaneous integrated boost (SIB), with concurrent Cisplatin 100 mg/m2 3 weekly] at our institution between November 2022 and November 2023 were retrieved from our digital archives. For each plan, 1 ring structure was created 3mm below the external skin surface, and the parameters V40, V50, V60 and Dmax were collected from the same. These parameters were correlated with grades of RD as per Common Terminology Criteria for Adverse Events (CTCAE) v5.0. The statistical analysis was done using MedCalc software version 22.021.

Results

The incidence of G2/G3 RD was 52.5%, and its incidence was significantly correlated with all of the four parameters. Statistically significant (p < 0.001) dosimetric predictive accuracy was provided by 71.66 cc, 29.98 cc and 7.624 cc of the 3mm skin ring V40, V50 and V60, respectively.

Conclusion

The dose distribution pattern to a skin layer stationed 3mm below the surface may help predict the development of severe RD in head and neck cancer patients receiving concurrent chemoradiation.

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.

The influence of different radiotherapy doses on the mechanical properties and microstructure of the enamel and dentin of human premolar teeth

OBJECTIVE

Radiation therapy is applied in the treatment of head and neck cancer patients. However, oral-health-related side effects like hyposalivation and a higher prevalence of caries have been shown. This study aims to assess the influence of different radiotherapy doses on the mechanical properties, roughness, superficial microstructure, and crystallinity of the enamel and dentin of human premolar teeth.

METHODS

Specimens (n = 25) were categorized into five groups based on the radiation dose received (0, 10, 30, 50, and 70 Gy). The enamel and dentin of these specimens were subjected to a microhardness tester, profilometer, atomic force microscopy (AFM), scanning electron microscopy (SEM), and X‑ray diffraction (XRD) before and after different irradiation doses and compared to hydroxylapatite in each group. The data were analyzed using repeated-measures analysis of variance (ANOVA).

RESULTS

Therapeutic radiation doses of 30, 50, and 70 Gy led to a decrease in the microhardness and an increase in the average roughness of the enamel, and rougher surfaces were observed in the mixed three-dimensional images. Moreover, in the dentin, a similar outcome could be observed for more than 10 Gy. The main crystalline phase structure remained hydroxylapatite, but the crystallinity decreased and the crystalline size increased above 10 Gy. The superficial micromorphology revealed granulation, fissures, and cracks in a dose-dependent manner. Radiation below 70 Gy had little effect on the hydroxylapatite concentration during the whole experiment.

CONCLUSION

Above a radiation dose of 30 Gy, the micromorphology of the tooth enamel changed. This occurred for dentin above 10 Gy, which indicates that dentin is more sensitive to radiotherapy than enamel. The radiation dose had an effect on the micromorphology of the hard tissues of the teeth. These results illustrate the possible mechanism of radiation-related caries and have guiding significance for clinical radiotherapy.

Time to Onset of Dysphagia Following Head and Neck Radiation

To evaluate the time of onset of dysphagia in a cohort of head and neck cancer patients treated with radiation or chemoradiation. Retrospective chart review of adult patients. 237 patients met inclusion criteria for the study. The average age at cancer diagnosis was 62 years (± 12.6) in a predominantly male cohort (n = 198, 83.5%). The most common subsite was oropharyngeal (n = 146, 60.8%) and squamous cell carcinoma in origin (n = 232, 97.9%). Of head and neck cancer patients diagnosed with new onset dysphagia or a dysphagia related diagnosis, nine (3.8%) were diagnosed at six months to 1 year, 12 (5.1%) at 1-2 years, and 17 (7.1%) at greater than 2 years. The mean radiation dose to the larynx was 43.8 Gy (Gy) (± 14.5) and statistically significant across time the periods (p = 0.018, η2 = 0.161). No difference was found between age, HPV status, T stage, smoking history, or tumor site. The majority of head and neck cancer patients treated with chemoradiation who developed dysphagia did so within the acute time period (during treatment and up to 6 months post treatment). However, a substantial proportion of patients also developed dysphagia in later time periods (16%). The incidence of dysphagia in certain time periods may be impacted by laryngeal radiation dose. Therefore, we recommend long term monitoring/screening of these patients so early intervention can occur.

Dosimetric Comparison and Selection Criteria of Intensity-Modulated Proton Therapy and Intensity-Modulated Radiation Therapy for Adaptive Re-Plan in T3-4 Nasopharynx Cancer Patients

BACKGROUND

Proton therapy requires caution when treating patients with targets near neural structures. Intuitive and quantitative guidelines are needed to support decision-making concerning the treatment modality. This study compared dosimetric profiles of intensity-modulated proton therapy (IMPT) and intensity-modulated radiation therapy (IMRT) using helical tomotherapy (HT) for adaptive re-planning in cT3-4 nasopharyngeal cancer (NPCa) patients, aiming to establish criteria for selecting appropriate treatment modalities.

METHODS

HT and IMPT plans were generated for 28 cT3-4 NPCa patients undergoing definitive radiotherapy. Dosimetric comparisons were performed for target coverage and high-priority organs at risk (OARs). The correlation between dosimetric parameters and RT modality selection was analyzed with the target OAR distances.

RESULTS

Target coverages were similar, while IMPT achieved better dose spillage. HT was more favorable for brainstem D1, optic chiasm Dmax, optic nerves Dmax, and p-cord D1. IMPT showed advantages for oral cavity Dmean. Actually, 14 IMPT and 14 HT plans were selected as adaptive plans, with IMPT allocated to most cT3 patients (92.9% vs. 42.9%, p = 0.013). The shortest distances from the target to neural structures were negatively correlated with OAR doses. Receiver operating characteristic curve analyses were carried out to discover the optimal cut-off values of the shortest distances between the target and the OARs (temporal lobes and brainstem), which were 0.75 cm (AUC = 0.908, specificity = 1.00) and 0.85 cm (AUC = 0.857, specificity = 0.929), respectively.

CONCLUSIONS

NPCa patients with cT4 tumor or with the shortest distance between the target and critical neural structures < 0.8 cm were suboptimal candidates for IMPT adaptive re-planning. These criteria may improve resource utilization and clinical outcomes.

Volumetric measurement to evaluate treatment response to induction chemotherapy on MRI outperformed RECIST guideline in outcome prediction in advanced nasopharyngeal carcinoma

BACKGROUND

Treatment response evaluated by tumour size change is an important indicator for outcome prediction. Advanced nasopharyngeal carcinoma (adNPC) grows irregularly, and so the unidimensional measurement may not be accurately applied to adNPC for outcome prediction. This study aimed to evaluate values of unidimensional and volumetric measurements for treatment response to induction chemotherapy (IC) for outcome prediction in adNPC and compared the values with that of RECIST 1.1 guideline.

MATERIALS AND METHODS

Pre-treatment and post-IC magnetic resonance images (MRIs) from 124 patients with stage III-IVA NPC were retrospectively reviewed. Sums of the maximum unidimensional diameters (D) and volumes of the targeted tumours (primary tumour and two largest metastatic lymph nodes) on the pre- (Dpre and Vpre) and post-IC MRIs (Dpost-IC and Vpost-IC) and percentage changes in D (Δ D%) and V (ΔV%) between two scans were calculated and correlated with disease-free survival (DFS), locoregional recurrence-free survival (LRRFS), and distant metastases-free survival (DMFS) using Cox regression analysis. Area under the curves (AUCs) of independent measurements and RECIST groups (RECIST response and non-response groups) for predicting disease recurrence, locoregional recurrence, and distant metastases, respectively, were calculated and compared using the DeLong test.

RESULTS

Univariable analysis showed correlations between high Dpost-IC with poor DFS and DMFS (P < 0.05), but not with LRRFS (P = 0.07); high Vpost-IC and low ΔV% (less decrease in volume on post-IC) with poor DFS, LRRFS, and DMFS (P < 0.05); and no correlations between Dpre, ΔD%, and Vpre and the outcomes (P > 0.05). Multivariable analysis showed that ΔV% was the only independent measurement for outcomes (P < 0.05). Compared with RECIST groups, ΔV% of 47.9% (median value) showed a higher AUC for disease recurrence (0.682 versus 0.526, P < 0.01) and for locoregional recurrence (0.782 versus 0.585, P < 0.01), but not for distant metastases (0.593 versus 0.518, P = 0.26).

CONCLUSIONS

Volumetric measurement to evaluate treatment response to IC outperformed unidimensional measurement and RECIST guideline in outcome prediction in adNPC.

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.

Tumor Hypoxia on 18F-fluoromisonidazole Positron Emission Tomography and Distant Metastasis From Head and Neck Squamous Cell Carcinoma

Importance

Given high rates of locoregional control after definitive management of head and neck squamous cell carcinoma (HNSCC), better methods are needed to project distant metastasis (DM) risk. Tumor hypoxia on 18F-fluoromisonidazole (FMISO) positron emission tomography (PET) is associated with locoregional failure, but data demonstrating an association with DM are limited.

Objective

To determine whether tumor hypoxia on FMISO PET is associated with DM risk after chemoradiotherapy (CRT) for HNSCC.

Design, Setting, and Participants

This cohort study assessed patients with HNSCC enrolled in 2 prospective clinical trials at a single academic referral center from 2004 to 2021 in which participants received FMISO PET before and during CRT. Data analysis occurred from May 2023 to May 2024.

Exposures

FMISO PET scans before and 1 to 2 weeks after starting CRT were evaluated for tumor hypoxia by nuclear medicine physicians.

Main Outcomes and Measures

The primary outcome was DM, defined as biopsy-proven HNSCC outside the primary site and regional lymph nodes. Time to DM was modeled with competing risk regression, with death as a competing risk. Overall survival (OS) was assessed secondarily and modeled with Cox regression.

Results

Among 281 patients (median [range] age at CRT, 58.7 [25.5-85.6] years; 251 male [89.3%]) included in this study, 242 (86.1%) had oropharyngeal primary cancer, and 266 (94.7%) had human papillomavirus-positive disease. Of all patients, 217 (77.2%) had T stage 1 or 2, and 231 patients (82.2%) had N stage 2b or less. De-escalated 30 Gy CRT was delivered to 144 patients (51.2%), and the remainder received standard 70 Gy CRT. On FMISO PET examination, 73 patients (26.0%) had hypoxia-negative disease before CRT, 138 patients (49.1%) had hypoxia-positive disease before CRT and then hypoxia-negative disease during CRT, and 70 patients (24.9%) persistently had hypoxia-positive disease before and during CRT. At a median (IQR) 58 (46-91) months of follow-up, 12 DM events and 22 deaths were observed. Persistent intratreatment hypoxia was associated with increased DM risk (hazard ratio, 3.51; 95% CI, 1.05-11.79; P = .04) and worse OS (hazard ratio, 2.66; 95% CI, 1.14-6.19; P = .02). No patients with hypoxia-negative disease before CRT experienced DM.

Conclusions and Relevance

In this cohort study using pooled analysis of prospective nonrandomized clinical trials incorporating FMISO PET in the definitive management of HNSCC, persistent intratreatment hypoxia was associated with increased risk of DM and worse OS. Conversely, all patients with hypoxia-negative disease before treatment remained free of DM. These findings suggest that pretreatment and intratreatment FMISO PET results may serve as biomarkers for DM risk and aid in identifying candidates for escalated therapeutic strategies.

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.

Deep learning with uncertainty estimation for automatic tumor segmentation in PET/CT of head and neck cancers: impact of model complexity, image processing and augmentation

Objective.Target volumes for radiotherapy are usually contoured manually, which can be time-consuming and prone to inter- and intra-observer variability. Automatic contouring by convolutional neural networks (CNN) can be fast and consistent but may produce unrealistic contours or miss relevant structures. We evaluate approaches for increasing the quality and assessing the uncertainty of CNN-generated contours of head and neck cancers with PET/CT as input.Approach.Two patient cohorts with head and neck squamous cell carcinoma and baseline18F-fluorodeoxyglucose positron emission tomography and computed tomography images (FDG-PET/CT) were collected retrospectively from two centers. The union of manual contours of the gross primary tumor and involved nodes was used to train CNN models for generating automatic contours. The impact of image preprocessing, image augmentation, transfer learning and CNN complexity, architecture, and dimension (2D or 3D) on model performance and generalizability across centers was evaluated. A Monte Carlo dropout technique was used to quantify and visualize the uncertainty of the automatic contours.Main results. CNN models provided contours with good overlap with the manually contoured ground truth (median Dice Similarity Coefficient: 0.75-0.77), consistent with reported inter-observer variations and previous auto-contouring studies. Image augmentation and model dimension, rather than model complexity, architecture, or advanced image preprocessing, had the largest impact on model performance and cross-center generalizability. Transfer learning on a limited number of patients from a separate center increased model generalizability without decreasing model performance on the original training cohort. High model uncertainty was associated with false positive and false negative voxels as well as low Dice coefficients.Significance.High quality automatic contours can be obtained using deep learning architectures that are not overly complex. Uncertainty estimation of the predicted contours shows potential for highlighting regions of the contour requiring manual revision or flagging segmentations requiring manual inspection and intervention.

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.