Dysphagia-optimised intensity-modulated radiotherapy versus standard intensity-modulated radiotherapy in patients with head and neck cancer (DARS): a phase 3, multicentre, randomised, controlled trial

Adaptive radiotherapy for oropharyngeal cancer with daily adapt-to-shape workflow on 1.5 T MRI-linac: Preliminary outcomes and comparison with helical tomotherapy

Introduction

MR-linac could offer several advantages for radical radiochemotherapy (RCHT) in oropharyngeal squamous cell carcinoma (OPSCC) patients. Currently, only a few case series have been published and no comparison with other techniques have been performed.

Methods

Data of 34 consecutive patients treated from September 2022 to May 2024 at a single Institution with RCHT on Unity® MR-linac for OPSCC with daily adaptive radiotherapy (RT) according to the adapt-to-shape (ATS) workflow were prospectively analyzed. A comparative cohort of 34 patients with similar characteristics treated with helical treatment on Radixact® was retrieved.

Results

Characteristics were well balanced across the two groups. Maximal toxicity grade ≥2 rate was borderline higher at RT end in MRI-linac group (p 0.049), but lower one month after RT (76.5 % vs 91.2 %; p = 0.257).Non-significantly lower rates of grade ≥2 xerostomia and dysgeusia were reported in Unity® group one and three months after RT. Higher rates of hospitalizations were reported in Radixact group at 20 fractions and at RT end (64.1 % vs 35.3 %; p = 0.015). Mean Karnofsky performance status (KPS) was higher in Unity group three months after RT (87.67 vs 83.87; p = 0.038).After a median follow up of 361.5 days, local complete response was reported for 93.6 % of patients treated with Unity® and 96.8 % of patients treated with Radixact®.

Conclusions

Results of this analysis support the feasibility of an ATS MR-linac workflow for RCHT in OPSCC. Compared with tomotherapy, treatment with Unity® resulted in significantly lower rates of hospitalization and higher KPS three months after RT. Grade 2 xerostomia and dysgeusia rates were non-significantly lower in Unity group. Optimal results in terms of local control were reported for both techniques.

Post-operative radiotherapy for oral cavity squamous cell carcinoma: Review of the data guiding the selection and the delineation of post-operative target volumes

BACKGROUND AND PURPOSE

To date, no consensus guidelines have been published that systematically guide delineation of primary and nodal Clinical Target Volumes (CTVs) in patients who require post-operative radiotherapy (PORT) for head and neck squamous cell carcinoma (HNSCC). As a result, significant individual, institutional and national variation exists in the way that CTVs are delineated in the post-operative setting, leading to considerable heterogeneity in radiotherapy treatment.

METHODS

A multi-disciplinary group of experts was convened by the European Society for Radiotherapy and Oncology (ESTRO), including radiation oncologists from Europe, North America and Asia, as well as surgery, radiology and pathology representatives. Oral cavity squamous cell carcinoma (OCSCC), where surgery followed by PORT is the standard of care, was first selected for focus. The indications for PORT, and the influence of tumour subsite and stage on post-operative treatment volumes, were considered with reference to current evidence, and clinical experience within the group.

RESULTS

We present clear recommendations regarding the indications for PORT in OCSCC, and propose a new classification of lateralised and non-lateralised OCSCC, to help guide the delineation of post-operative nodal CTVs.

CONCLUSIONS

The evidence and expert opinion summarised in this manuscript provides the background and context required to underpin new international consensus guidelines for the delineation of primary and nodal CTVs for OCSCC in the post-operative setting.

New trends in supportive care of head and neck cancers

PURPOSE OF REVIEW

Supportive care plays a vital role in the management of head and neck cancer (HNC) patients, as the disease often affects a frail and older population that is treated with multiple strategies and is associated with severe symptoms. We will focus on mucositis, dermatitis, dysphagia, pain, cachexia, and infections, as they are among the most common and challenging symptoms encountered.

RECENT FINDINGS

Efforts have focused on multiomics approaches to decipher the complex biological pathways that drive symptom onset and treatment-related toxicities, with the aim of developing novel therapeutic strategies. A notable example is ponsegromab, a monoclonal antibody designed to target cancer cachexia. Other promising areas of research, such as machine-learning models and the role of oral and gut microbiota on cachexia and mucositis, are actively being explored; however, their impact to date remains limited.

SUMMARY

In recent years, new knowledge has emerged regarding the underlying causes and predictive models for the supportive care of HNC patients. Unfortunately, this expanding body of knowledge primarily adds to complexity without translating into practical applications or substantial improvements for patients. Future efforts should prioritize the standardization of therapeutic algorithms, and the generation of robust evidence based on existing preclinical models.

Clinical Benefit and Safety of Reduced Elective Dose in Definitive Radiotherapy for Head and Neck Squamous Cell Carcinoma: The UPGRADE-RT Multicenter Randomized Controlled Trial

PURPOSE

Definitive radiotherapy (RT) for head and neck cancer (HNC) has significant long-term toxicity with elective neck irradiation (ENI) as a major contributor. In this multicenter randomized trial, the clinical benefit and safety of definitive RT with reduced versus standard elective dose were compared.

METHODS

Newly diagnosed patients with cT2-4N0-2M0 HNC were accrued and treated in five Dutch centers (definitive accelerated RT, 68 Gy in 34 fractions in 5.5 weeks). Patients receiving concurrent chemotherapy were not eligible. Dose for ENI was randomly assigned (2:1; dose reduction, 43 Gy, versus control, 50 Gy). The primary outcome was normalcy of diet score at 1 year. The secondary outcome was recurrence in electively irradiated nodes at 2 years in the dose reduction group with the null hypothesis rejected if the upper-bound one-sided 95% CI exceeded 9%.

RESULTS

Between 2016 and 2022, 300 patients were randomnly assigned, of whom 295 were evaluable and included in analysis (dose reduction, 196 and control, 99). The mean normalcy of diet score at 1 year was 91.6 (95% CI, 88.5 to 94.7) in the dose reduction group and 92.6 (95% CI, 88.2 to 97.1) in the control group (mean difference, -1.1 [95% CI, -6.5 to 4.4]). The 2-year recurrence rate in electively irradiated nodes in the dose reduction group was 4.9% (upper-bound one-sided 95% CI, 7.5%). In the control group, this was 4.3% (upper bound one-sided 95% CI, 7.7%). Exploratory analyses demonstrated less acute dysphagia grade ≥3 and better xerostomia-related quality of life in the dose reduction group.

CONCLUSION

This is the second randomized controlled trial demonstrating that reduced elective dose is safe in definitive RT for HNC.

Analysis of factors related to radiation-induced oral mucositis in patients with head and neck tumors undergoing radiotherapy

OBJECTIVE

To explore the risk factors of radiation-induced oral mucositis (RIOM) in patients with head and neck tumors undergoing radiotherapy.

METHODS

A retrospective collection was conducted on patients with head and neck tumors who underwent radiotherapy and chemotherapy in our hospital from April 1, 2015 to April 1, 2019. They were divided into an incidence group (n = 48) and a non-incidence group (n = 76) based on whether RIOM occurred, and relevant data was collected for comparison.

RESULTS

There were statistically significant differences between the two groups of patients in terms of tumor type, smoking percentage, education level percentage, tumor stage, oral mucosal inflammation stage, radiotherapy dose, mucosal protectants, and oral hygiene condition(P < 0.05); The regression analysis results showed that smoking (OR=1.274, 95 % CI: 1.095-2.007), high-dose radiotherapy (OR=1.223, 95 % CI: 1.098-2.077), and poor oral hygiene (OR=1.367, 95 % CI: 1.024-2.890) were risk factors for RIOM.

CONCLUSION

Smoking, high-dose radiotherapy, and poor oral hygiene were risk factors for RIOM in head and neck patients after radiotherapy and chemotherapy.

Online Radiotherapy: The Paradigm Shift to Real-Time Adaptive Radiotherapy

BACKGROUND

Adaptive radiotherapy (ART) involves the continuous adaptation of the radiation plan according to patient- and tumorspecific feedback. In online ART, the plan is optimized in real time during the treatment; in offline ART, the plan is recalculated between treatment sessions. Hybrid linear accelerators with integrated CT, MRI, or PET are required to perform online ART.

METHODS

This review is based on clinically relevant studies on online ART (January 2019 - May 2024) that were retrieved by a selective search in PubMed.

RESULTS

Online ART is a new technique for which no phase 3 trials have been published; in contrast, multiple randomized trials are already available for offline ART. The initial findings of a random - ized phase 2 trial of online ART for head and neck cancer showed lower rates of G2 or higher radiation-induced dermatitis (8% vs. 31%, p = 0.05) and a lower dose to the parotid gland (mean dose: 11.5 Gy vs. 16.0 Gy, p = 0.02) with online ART compared to standard radiochemotherapy. Moreover, observational studies show that online ART is feasible and spares organs at risk in patients with esophageal, pancreatic, rectal, and prostatic cancer. Additionally, online ART can enable simulation-free treatment planning and faster initiation of radiotherapy. It is, however, more demanding of time and resources and more costly than standard radiotherapy, and no studies with long-term clinical endpoints are available to date.

CONCLUSION

Initial studies confirm the feasibility of online ART and arouse the hope that it will enable more precise radiotherapy with less damage to surrounding structures. Phase 3 trials are needed so that the patient groups who stand to benefit most from online ART can be identified.

Toxicity and Oncologic Outcomes of Proton Radiotherapy for Oropharyngeal Cancer: A Systematic Review and Meta-Analysis

Intensity-modulated radiotherapy (IMRT) for oropharyngeal cancer (OPC) is associated with acute and late toxicities that impact patient quality of life. Proton radiotherapy (PRT) can reduce exposure to surrounding tissues, but the clinical magnitude of this advantage is unclear. A systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Included studies reported toxicity or oncologic outcomes from patients treated with PRT for OPC. Pooled outcomes were estimated using random-effects models. Comparisons between PRT and IMRT were performed using log odds ratios. Primary outcomes were the pooled rates of adverse events, overall survival (OS), and progression-free survival (PFS). A total of 18 studies (16 retrospective, two prospective) consisting of 956 patients were identified. Pooled rates of acute grade 3+ toxicities were as follows: dermatitis 19%, mucositis 32%, xerostomia 1.3%, dysphagia 13%, and weight loss 1.4%. The pooled rate of acute hospitalizations was 10%. Among studies reporting late toxicities, the rates of grade 3+ xerostomia and dysphagia were 1.1% and 1.6%, respectively. Compared to IMRT, PRT was associated with lower rates of acute feeding tube use (21% versus 31%; P = 0.0012), but not long-term feeding tube use (1.4% versus 2.7%; P = 0.24). After PRT, OS at two and three years were 98% and 96%, while PFS at two and three years were 93% and 86%. PRT for patients with OPC is associated with favorable toxicity and oncologic outcomes. While randomized clinical trials are ongoing, these data provide additional evidence regarding the efficacy of PRT in the upfront treatment of OPC.

Association between Swallowing Outcomes and Dose to Critical Swallow Structures in Patients Undergoing Transoral Robotic Surgery and Post-Operative Radiation Therapy

BACKGROUND

The radiation dose to dysphagia and aspiration-related structures (DARS) for patients undergoing transoral robotic surgery (TORS) and post-operative radiation therapy (PORT) for primary oropharyngeal carcinoma is unknown.

METHODS

This prospective study measured swallowing using the MD Anderson Dysphagia Inventory at baseline and then 12-months after PORT. Dosimetric parameters were collected.

RESULTS

19 patients were recruited between 2017 and 2019. Worse swallow function at 12-months after PORT was associated with dose-parameters to the oesophageal inlet muscle, superior pharyngeal constrictor muscle and cervical oesophagus. Mean dose, V50Gy, and V60Gy to the base of tongue and pharyngeal constrictors was significantly lower in those receiving PORT to the neck alone.

CONCLUSION

Dose to DARS was lower in patients who received PORT to the neck alone. In patients treated with TORS and PORT, poorer swallowing outcomes at 12 months post-treatment were associated with increased dose to oesophageal inlet muscle, superior constrictor muscle, and cervical oesophagus.

Deglutition preservation after swallowing (SWOARs)-sparing IMRT in head and neck cancers: definitive results of a multicenter prospective study of the Italian Association of Radiotherapy and Clinical Oncology (AIRO)

BACKGROUND

To investigate changes of objective instrumental measures and correlate with patient reported outcomes (PROs) of radiation-induced dysphagia (RID) after swallowing organs at risk (SWOARs)-sparing IMRT.

METHODS

Patients (pts) underwent Fiberoptic Endoscopic Evaluation of Swallowing (FEES), Videofluoroscopy (VFS) and M.D. Anderson Dysphagia Inventory (MDADI) questionnaire at baseline, 6 and 12 months after treatment. They were categorized in two groups: MDADI-C ≥ 80 and MDADI-C < 80. Pharyngeal residue (PR) and penetration (P) or aspiration (A) were considered as surrogate of RID.

RESULTS

Between 2016 and 2022 we enrolled 75 pts, 40 (53 %) MDADI-C ≥ 80 and 35 (47 %) MDADI-C < 80 at baseline. Among MDADI-C ≥ 80 the mean baseline PR score at FEES was 0,42 rising to 1,36 at 6 months (p = 0,001) and stabilizing to 1,15 at 12 months (p = 0,21); indeed, the mean baseline PR score at VFS was 0,55 rising to 1 at 6 months (p = 0,069) and slightly dropping to 0,7 at 12 months (p = 0,069). Among MDADI-C < 80 the mean baseline PR score at FEES was 0,56 rising to 1,07 at 6 months (p = 0,012) and stabilizing to 1,07 at 12 months (p = 0,99); indeed the mean baseline PR score at VFS was 0,67 rising to 1,19 at 6 months (p = 0,04) and dropping to 0,78 at 12 months (p = 0,04). No correlation was found between PROs and objective measures.

CONCLUSION

Our results show optimal acceptable deglutition preservation from major complications after SWOARs-sparing IMRT by means of low objective scores in both MDADI-C groups. Lack of correlation between PROs and objective measures suggest that referred RID is likely associated to persistence of SWOARs inflammation rather than to a real impairment of function.

Prediction of the need of enteral nutrition during radiation therapy for head and neck cancers

INTRODUCTION

Patients with a head and neck (HN) cancer undergoing radiotherapy risk critical weight loss and oral intake reduction leading to enteral nutrition. We developed a predictive model for the need for enteral nutrition during radiotherapy in this setting. Its performances were reported on a real-world multicentric cohort.

MATERIAL AND METHODS

Two models were trained on a prospective monocentric cohort of 230 patients. The first model predicted an outcome combining severe or early fast weight loss, or severe oral intake impairment (grade 3 anorexia or dysphagia or the prescription of enteral nutrition). The second outcome only combined oral intake impairment criteria. We trained a gradient boosted tree with a nested cross validation for Bayesian optimization on a prospective cohort and predictive performances were reported on the external multicentric real-world cohort of 410 patients from 3 centres. Predictions were explainable for each patient using Shapley values.

RESULTS

For the first and second outcome, the model yielded a ROC curve AUC of 81 % and 80%, an accuracy of 77 % and 77 %, a positive predictive value of 77 % and 72 %, a specificity of 78 % and 79 % and a sensitivity of 75 % and 73 %. The negative predictive value was 80 % and 80 %. For each patient, the underlying Shapley values of each clinical predictor to the prediction could be displayed. Overall, the most contributing predictor was concomitant chemotherapy.

CONCLUSION

Our predictive model yielded good performance on a real life multicentric validation cohort to predict the need for enteral nutrition during radiotherapy for HN cancers.

Impact of radiotherapy-related late toxicities of skin and soft tissue in the neck on quality of life in head and neck cancer patients: a multi-institutional observational study in Japan

PURPOSE

This multi-institutional observational study aimed to assess the incidence, severity, and impact of radiotherapy-related late toxicities of the cervical skin and soft tissue in head and neck cancer patients. We also explored patient interest in fat grafting as a potential treatment for skin and soft tissue sequelae.

METHODS

This study was conducted across 19 institutions in Japan. The study involved head and neck cancer patients who received ≥ 60 Gy of cervical radiotherapy concomitant with a history of neck dissection and were free of cancer recurrence ≥ 3 years after the final treatment. Consenting outpatients completed a self-administered questionnaire to collect data on symptom severity and the attending outpatient physicians reported data on demographics and treatments in a case report form.

RESULTS

A total of 222 patients were enrolled. The incidence proportion of late cervical skin and soft tissue toxicities was 96%, with 32% of patients reporting their symptoms as severe, and 69% of patients reporting an impact on quality of life (QOL). An interest in or consideration of fat grafting was reported by 34% of patients, with a greater desire among those with severe symptoms.

CONCLUSION

This study elucidated the incidence, severity, and life impact of late toxicities affecting the cervical skin and soft tissue after radiotherapy for head and neck cancer. These late toxicities were highly prevalent and significantly impacted QOL. There is a substantial demand for new treatments, such as fat grafting, to address these complications and enhance the QOL for survivors of head and neck cancer.

Emerging Radiotherapy Technologies for Head and Neck Squamous Cell Carcinoma: Challenges and Opportunities in the Era of Immunotherapy

Radiotherapy (RT) is an integral component in the multidisciplinary management of patients with head and neck squamous cell carcinoma (HNSCC). Significant advances have been made toward optimizing tumor control and toxicity profiles of RT for HNSCC in the past two decades. The development of intensity modulated radiotherapy (IMRT) and concurrent chemotherapy established the standard of care for most patients with locally advanced HNSCC around the turn of the century. More recently, selective dose escalation to the most radioresistant part of tumor and avoidance of the most critical substructures of organs at risk, often guided by functional imaging, allowed even further improvement in the therapeutic ratio of IMRT. Other highly conformal RT modalities, including intensity modulated proton therapy (IMPT) and stereotactic body radiotherapy (SBRT) are being increasingly utilized, although there are gaps in our understanding of the normal tissue complication probabilities and their relative biological effectiveness. There is renewed interest in spatially fractionated radiotherapy (SFRT), such as GRID and LATTICE radiotherapy, in both palliative and definitive settings. The emergence of immune checkpoint inhibitors (ICIs) has revolutionized the treatment of patients with recurrent and metastatic HNSCC. Novel RT modalities, including IMPT, SBRT, and SFRT, have the potential to reduce lymphopenia and immune suppression, stimulate anti-tumor immunity, and synergize with ICIs. The next frontier in the treatment of HNSCC may lie in the exploration of combined modality treatment with new RT technologies and ICIs.

Global assessment of swallow function (GASF) following VMAT radiotherapy for head and neck squamous cell carcinoma

Aim

This study aimed to conduct a global assessment of swallow function (GASF) using a range of swallow outcome tools, in a cohort of patients pre- and post-treatment with image-guided volumetric modulated arc therapy (VMAT) radiotherapy.

Materials and methods

All patients receiving radical (chemo)radiation for SCC of the larynx, oro-, hypo- or nasopharynx between October 2016 - 2021 were eligible for inclusion.Patients were treated with VMAT radiotherapy according to institutional and national protocols.Patients underwent GASF pre- and 6 months post-treatment. Data were collated from the MD Anderson Dysphagia Inventory (MDADI), the Functional Oral Intake Scale (FOIS), the Performance Status Scale-Head and Neck: Normalcy of Diet scale (PSS-NoD), the 100 ml water swallow test (WST) for capacity and maximal interincisal opening (MIO).

Results

One hundred and seventy-five patients were included. 55.2 % of patients experienced a fall in MDADI-Composite score greater than the published meaningful clinical important difference (MCID).A trend for a decrease in FOIS score reflects a decrease in range of diet textures and increase in reliance on enteral feeding at 6 months post-treatment.Mean PSS-NoD score decreased reflecting increased restriction in diet textures.20 patients' WST capacity improved by the minimal clinically important difference of > 4mls whilst 37 % of patients experienced a decrease in WST capacity of 4mls or more. 12.6 % of patients developed trismus following radiotherapy.

Conclusions

This paper adds new detail to the understanding of the decline in measured eating, drinking and swallowing function that patients treated with VMAT radiotherapyexperience at 6 months post treatment. However, gaps are highlighted in the evidence base in terms of interpretation of swallow outcomes tool scores; future research in HNC should include ongoing discussion and development around robust outcomes tools and data collection.

The timed 100 mL water swallow test for patients with head and neck cancer: What constitutes a clinically significant difference?

OBJECTIVES

Swallowing function in patients with head and neck cancer (HNC) is often assessed pre-treatment, during and at intervals post-treatment to identify those with dysphagia as early as possible. This study aims to investigate the minimal clinical important difference (MCID) for the 100 mL water swallow test (100 mL WST) to increase its utility in clinical practice and in clinical trials.

METHODS

Data from 211 HNC patients, treated by either single or combined modality were included. Patients completed both the 100 mL WST and M.D. Anderson Dysphagia Inventory (MDADI) at baseline (i.e., prior to treatment) and 12 months post-treatment. The MCID for the 100 mL WST was calculated using two approaches of the anchor-based method (using the MDADI), including mean change, and ROC curve. Additionally, the distribution-based method was used utilizing the half standard deviation approach.

RESULTS

In the anchor-based method, a 4 mL/s in the 100 mL WST was defined as an MCID for deterioration, with a sensitivity of 75% and a 1-specificity of 46%. In contrast, a change of 5 mL/s was deemed as an MCID for improvement, based on the distribution-based method.

CONCLUSION

The findings showed that deterioration of 4 mL, or an increase of 5 mL from baseline to 12 months post-HNC treatment equates to an MCID from the patients' perspective. Based on these findings, it may be beneficial to increase the utilization of the 100 mL WST in clinical practice to observe the changes, and in clinical trials to interpret and compare different study arms.

Preliminary experience using MR-guided adaptive radiotherapy in head and neck cancer

This retrospective study evaluates the dosimetric benefits of adaptive radiotherapy for head and neck cancer patients. Five patients with node-positive oropharyngeal squamous cell carcinoma were treated with MR-guided radiotherapy using the Elekta Unity MR-Linac, undergoing 3-4 offline adaptive plan modifications during their treatment. This study compared the dose delivered to organs at risk (OARs) in a full offline adaptive approach versus an approach accounting only for daily setup. Results demonstrated a reduction in mean dose to critical structures in the offline adaptive arm. For example, the pharynx avoidance structure showed mean dose reductions ranging from 1.4 Gy to 3.6 Gy, and the left parotid gland exhibited reductions from 1.5 Gy to 1.9 Gy. Overall, offline adaptive radiotherapy reduced the mean cumulative dose to OARs in 19 of the 23 evaluated structures. Despite some instances of higher doses, the offline adaptive approach generally resulted in lower cumulative doses, emphasizing its potential to mitigate radiation-induced side effects. These findings suggest that offline adaptive radiotherapy has the potential to enhance treatment efficacy by better accommodating anatomical changes during therapy, thereby improving patient outcomes and reducing treatment-related morbidity.

Pyroptosis induced by natural products and their derivatives for cancer therapy

Natural products, which are compounds extracted and/or refined from plants and microbes in nature, have great potential for the discovery of therapeutic agents, especially for infectious diseases and cancer. In recent years, natural products have been reported to induce multiple cell death pathways to exhibit antitumor effects. Among them, pyroptosis is a unique programmed cell death (PCD) characterized by continuous cell membrane permeability and intracellular content leakage. According to the canonical and noncanonical pathways, the formation of gasdermin-N pores involves a variety of transcriptional targets and post-translational modifications. Thus, tailored control of PCD may facilitate dying cells with sufficient immunogenicity to activate the immune system to eliminate other tumor cells. Therefore, we summarized the currently reported natural products or their derivatives and their nano-drugs that induce pyroptosis-related signaling pathways. We reviewed six main categories of bioactive compounds extracted from natural products, including flavonoids, terpenoids, polyphenols, quinones, artemisinins, and alkaloids. Correspondingly, the underlying mechanisms of how these compounds and their derivatives engage in pyroptosis are also discussed. Moreover, the synergistic effect of natural bioactive compounds with other antitumor therapies is proposed as a novel therapeutic strategy for traditional chemotherapy, radiotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, hyperthermal therapy, and sonodynamic therapy. Consequently, we provide insights into natural products to develop a novel antitumor therapy or qualified adjuvant agents by inducing pyroptosis, which may eventually be applied clinically.

A Hard Truth to Swallow: Critically Evaluating the MD Anderson Dysphagia Inventory (MDADI) as an Endpoint in Human Papillomavirus-associated Oropharyngeal Cancer Trials

The MD Anderson Dysphagia Inventory (MDADI), a measure of swallowing-related quality of life, has become the preferred patient-reported outcome measure (PROM) in contemporary clinical trials evaluating the experience of human papillomavirus-associated oropharyngeal squamous cell carcinoma (HPVOPSCC) survivors. With many potentially practice-changing studies using the MDADI composite score as either a primary or coprimary endpoint, or as a key secondary endpoint, it is important to understand its psychometric properties as judged by contemporary PROM standards, with a particular focus on its application to contemporary HPVOPSCC populations. In this critical review, we evaluate contemporary HPVOPSCC studies reporting MDADI outcomes, followed by a detailed evaluation of the psychometric properties of the MDADI. Although the focus of this review was the MDADI, the issues discussed are not unique to the MDADI and have broader applicability to the evaluation and assessment of other PROMs currently in use. First, it may be possible to improve administration of the instrument, as related to missing items, scoring, and the number of items required. Second, although in many instances, the MDADI has been intended as a direct or surrogate measure of swallowing physiology, the MDADI composite score captures a broader health-related quality of life construct affected by both swallowing and eating, the latter of which may be affected by a range of nonswallowing treatment-related toxicities. Finally, a clinically meaningful change of 10 in the MDADI composite score, widely accepted and applied to the clinical trial setting, represents an undoubtably clinically relevant difference in unselected head and neck cancer survivors. However, the smallest difference that might be clinically important to a highly functional HPVOPSCC cohort remains uncertain. Understanding the purpose and properties of the MDADI instrument and furthering the sophistication with which we apply it in this population would improve its interpretation in clinical trials.

Preserving Laryngo-Esophageal Function in Patients With Hypopharyngeal Cancer Treated With Radiotherapy: Predictive Factors and Long-Term Outcomes

BACKGROUND

Functional outcomes after hypopharyngeal cancer (HPC) treatment have a significant effect on patients' quality of life and prognosis. This study aimed to identify the predictive factors associated with laryngo-esophageal dysfunction in patients with HPC who received definitive radiotherapy.

METHODS

Patients with HPC treated with definitive intensity-modulated radiotherapy between 2007 and 2019 at our institution were retrospectively evaluated. Laryngo-esophageal dysfunction-free survival (LDFS) events were defined as local recurrence, laryngo-esophageal dysfunction (defined as tracheostomy or feeding tube dependence), or death from any cause.

RESULTS

The median follow-up period was 61 months for the 80 patients included in the study. The 5-year LDFS rate was 47%. A clinical T4 stage and lower pretreatment prognostic nutritional index (PNI) were independently associated with a lower LDFS.

CONCLUSION

A clinical T4 stage and lower pretreatment PNI were identified as predictors of a lower LDFS after definitive radiotherapy for HPC.

Pilot Feasibility and Safety Study of Hydrogen Gas Inhalation in Locally Advanced Head and Neck Cancer Patients

Purpose

Hydrogen (H2) gas inhalation might alleviate acute radiotherapy toxicities by scavenging free radicals produced by ionizing radiation and anti-inflammatory properties. This study aimed to investigate the feasibility and safety of H2 gas inhalation during concurrent chemoradiotherapy (CCRT) in patients with locally advanced head and neck cancer (LAHNC).

Patients and Methods

We designed a pilot prospective study combining CCRT with aerosol inhalation of H2 gas. Each patient was scheduled to receive daily intensity-modulated radiotherapy (IMRT) in 33 fractions on a weekday and six cycles of weekly chemotherapy. All patients inhaled H2 gas through a cannula or mask 1 hour per day, 1-2 hours before IMRT. The primary endpoint was the feasibility of H2 inhalation. Eighty percent of the patients who completed at least 20 applications of H2 gas inhalation were considered feasible. The secondary endpoints were safety profiles during H2 gas inhalation (vital signs and symptoms related to H2 gas inhalation) and acute toxicities during CCRT.

Results

We enrolled 10 patients with LAHNC between July 2023 and December 2023. All patients received 33 fractions of H2 gas inhalation on the same day as the IMRT. Vital signs during and at the end of H2 gas inhalation were stable in all patients. None of the 10 patients had hypertension or hypotension during any of the 33 inhalations. No adverse events related to H2 gas inhalation, such as cough, nasal bleeding, dizziness, headache, nausea, or vomiting, were reported. Grade 3 leukopenia was found in two patients (20%) during the 5th week of CCRT. Grade 2 radiation dermatitis and pharyngitis were found in three patients (30%).

Conclusion

H2 gas inhalation combined with CCRT is feasible and safe for patients with LAHNC.

Radiation Therapy for HPV-Positive Oropharyngeal Squamous Cell Carcinoma: An ASTRO Clinical Practice Guideline

PURPOSE

Human Papilloma Virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is a distinct disease from other head and neck tumors. This guideline provides evidence-based recommendations on the critical decisions in its curative treatment, including both definitive and postoperative radiation therapy (RT) management.

METHODS

ASTRO convened a task force to address 5 key questions on the use of RT for management of HPV-associated OPSCC. These questions included indications for definitive and postoperative RT and chemoradiation; dose-fractionation regimens and treatment volumes; preferred RT techniques and normal tissue considerations; and posttreatment management decisions. The task force did not address indications for primary surgery versus RT. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Concurrent cisplatin is recommended for patients receiving definitive RT with T3-4 disease and/or 1 node >3 cm, or multiple nodes. For similar patients who are ineligible for cisplatin, concurrent cetuximab, carboplatin/5-fluorouracil, or taxane-based systemic therapy are conditionally recommended. In the postoperative setting, RT with concurrent cisplatin (either schedule) is recommended for positive surgical margins or extranodal extension. Postoperative RT alone is recommended for pT3-4 disease, >2 nodes, or a single node >3 cm. Observation is conditionally recommended for pT1-2 disease and a single node ≤3 cm without other risk factors. For patients treated with definitive RT with concurrent systemic therapy, 7000 cGy in 33 to 35 fractions is recommended, and for patients receiving postoperative RT without positive surgical margins and extranodal extension, 5600 to 6000 cGy is recommended. For all patients receiving RT, intensity modulated RT over 3-dimensional techniques with reduction in dose to critical organs at risk (including salivary and swallowing structures) is recommended. Reassessment with positron emission tomography-computed tomography is recommended approximately 3 months after definitive RT/chemoradiation, and neck dissection is recommended for convincing evidence of residual disease; for equivocal positron emission tomography-computed tomography findings, either neck dissection or repeat imaging is recommended.

CONCLUSIONS

The role and practice of RT continues to evolve for HPV-associated OPSCC, and these guidelines inform best clinical practice based on the available evidence.

Dysphagia in Head and Neck Cancer

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

De-Escalation Strategies in HPV-Associated Oropharynx Cancer: A Historical Perspective with Future Direction

The incidence of HPV-related oropharyngeal cancers has increased in recent decades. While cure rates exceed those of HPV-negative head and neck cancers, both acute and long-term sequelae of chemotherapy, radiation and surgery have led to clinical investigation into de-escalation of treatment. De-escalation trials have sought to reduce long-term treatment-related morbidity by altering or omitting chemotherapy, reducing radiation, or incorporating less invasive surgical resection through transoral surgery. More recent approaches include the use of novel agents such as immunotherapy in place of cisplatin. With the advent of tumor-tissue-modified HPV DNA detection and monitoring in blood, new strategies incorporating this biomarker are being developed.

A systematic review of antibody-drug conjugates and bispecific antibodies in head and neck squamous cell carcinoma and nasopharyngeal carcinoma: Charting the course of future therapies

INTRODUCTION

There is a need to improve the outcomes of patients with head and neck squamous cell carcinoma (HNSCC) and nasopharyngeal carcinoma (NPC), especially in recurrent unresectable and metastatic (R/M) setting. Antibody-drug conjugates (ADC) and bispecific antibodies (BsAb) may deliver promising results.

METHODS

We conducted a systematic literature review to identify ADC and BsAb clinical trials, involving patients with HNSCC and NPC, from database creation to December 2023. We reported trial characteristics, overall response rate (ORR), overall survival (OS), and grade ≥ 3 treatment-related adverse events (trAEs).

RESULTS

23 trials (65 % phase I) were found, involving 540 R/M patients (355 [20trials] HNSCC and 185 [5trials] NPC). There were 13 ADC (n = 343) and 10 BsAb (n = 197) trials. 96 % patients were refractory to standard of care treatments. ORR ranged from 0 to 100 %, with the highest ORR for GEN1042 plus chemoimmunotherapy. ORRs for monotherapies were 47 % for ADC, and 0-37 % for BsAb. MRG003 reached in HNSCC 43 % and NPC 47 %. BL-B01D1 54 % in NPC. Longest median OS was seen with MRG003 and KN046. Grade ≥ 3 trAEs were 28-60 % in ADC trials, and 3-33 % BsAb. Grade ≥ 3 myelosuppressive trAEs were typically seen in 8 ADC trials, while 4 BsAb showed infusion-related reactions (IRR). Four treatment-related deaths were reported (1 pneumonitis), all ADC trials.

CONCLUSION

ADC and BsAb antibodies show promise in R/M HNSCC and NPC. Results are premature by small sample sizes and lack of control arm. ADC mainly caused myelosuppression and a pneumonitis case, and BsAb IRR. Further research is warranted in this setting.

Multidisciplinary survey on use of feeding tubes in head and neck cancer patients undergoing chemoradiotherapy in Germany-the SUFEETUBE project

BACKGROUND AND OBJECTIVE

Data on enteral tube feeding in head and neck cancer (HNC) patients undergoing chemoradiotherapy vary considerably between German institutions. This survey aims to investigate the management of feeding tubes in an interdisciplinary context across Germany.

MATERIALS AND METHODS

Between December 2022 and May 2023, 70 participants (42 radiation oncologists, 12 medical oncologists, 14 head and neck surgeons, and 2 physicians covering several specialties) responded to our web-based survey. In addition to the type of institution (university hospital, private practice, etc.), their age, and professional experience (in years), participants were asked several questions on the indication and institutional policy for tube placement and management (prophylactic/reactive nasogastric or gastrostomy tube). All questions were mandatory single- or multiple-choice questions, while additional comments were possible by email.

RESULTS

Most participants were employed at a university hospital (n = 52; 74.3%) and came from a radiation oncology background (n = 42; 60%). Fifty-four contributors (77.1%) reported that no nutritional risk screening prior to chemoradiotherapy was routinely performed, and 71.4% (n = 50) stated that no standardized protocol was used at the institution to set the indication for tube placement. Generally, policies and methods of tube feeding vary considerably between the individual institutions and specialties. However, the majority (n = 56, 80%) recommended a prophylactic percutaneous enteral gastrostomy (PEG) tube to their patients before chemoradiotherapy. Still, there was no consistent trend regarding the approach for reactive tube feeding.

CONCLUSION

The policies and methods of tube feeding vary considerably between the individual institutions and specialties in Germany. In the era of individualized medicine, uniform protocols are difficult to establish. However, a baseline nutritional risk screening could simplify decision-making in clinical practice.

Reducing Salivary Toxicity with Adaptive Radiotherapy (ReSTART): A Randomized Controlled Trial Comparing Conventional IMRT to Adaptive IMRT in Head and Neck Squamous Cell Carcinomas

BACKGROUND

The utility of Adaptive Radiotherapy (ART) in Head and Neck Squamous Cell Carcinoma (HNSCC) remains to be ascertained. While multiple retrospective and single-arm prospective studies have demonstrated its efficacy in decreasing parotid doses and reducing xerostomia, adequate randomized evidence is lacking.

METHODS AND ANALYSIS

ReSTART (Reducing Salivary Toxicity with Adaptive Radiotherapy) is an ongoing phase III randomized trial of patients with previously untreated, locally advanced HNSCC of the oropharynx, larynx, and hypopharynx. Patients are randomized in a 1:1 ratio to the standard Intensity Modulated Radiotherapy (IMRT) arm {Planning Target Volume (PTV) margin 5 mm} vs. Adaptive Radiotherapy arm (standard IMRT with a PTV margin 3 mm, two planned adaptive planning at 10th and 20th fractions). The stratification factors include the primary site and nodal stage. The RT dose prescribed is 66Gy in 30 fractions for high-risk PTV and 54Gy in 30 fractions for low-risk PTV over six weeks, along with concurrent chemotherapy. The primary endpoint is to compare salivary toxicity between arms using salivary scintigraphy 12 months' post-radiation. To detect a 25% improvement in the primary endpoint at 12 months in the ART arm with a two-sided 5% alpha value and a power of 80% (and 10% attrition ratio), a sample size of 130 patients is required (65 patients in each arm). The secondary endpoints include acute and late toxicities, locoregional control, disease-free survival, overall survival, quality of life, and xerostomia scores between the two arms.

DISCUSSION

The ReSTART trial aims to answer an important question in Radiation Therapy for HNSCC, particularly in a resource-limited setting. The uniqueness of this trial, compared to other ongoing randomized trials, includes the PTV margins and the xerostomia assessment by scintigraphy at 12 months as the primary endpoint.

Proposals for the delineation of neck clinical target volume for definitive Radiation therapy in patients with oral/ oropharyngeal squamous cell cancer based on lymph node distribution

PURPOSE/OBJECTIVE(S)

To establish the distribution pattern of cervical lymph node metastasis (LNM) and propose optimized clinical target volume (CTV) boundaries specific to oral/ oropharyngeal squamous cell cancer (OSCC/OPSCC).

MATERIALS/METHODS

531 patients with pathologically confirmed OSCC/OPSCC were enrolled from January 2013 to June 2022. Patients were stratified into two groups based on the minimal distance from the lesion's edge to the body's midline: ≤1 cm or > 1 cm. The geometric center of cervical metastatic LN was marked on a template CT. LN distribution probability maps were established. The relationships between the LN distribution and consensus guidelines were analyzed to propose modifications for CTV boundaries specific to OSCC/OPSCC.

RESULTS

A total of 1962 positive LNs were enrolled. Compared with the > 1 cm group, the ≤ 1 cm group has following feature tendencies: male smokers, younger, median organs, large gross lesion, infiltrative growth pattern, contralateral LNM. The most frequently involved level of LNM was ipsilateral II, but ipsilateral Ib had the highest involvement rate in the > 1 cm OSCC group. In addition, tongue cancer had a higher incidence of LN extranodal extension (ENE), which mainly distributes in ipsilateral level II. The skip metastasis was prone to from level III to Vb (3.5 %) in LN(+)/ENE (-), and level Ib to VIa (3.7 %) in LN(+)/ENE (+). Accordingly, we proposed the following modifications: 1. only including lateral and posterior margin of submandibular gland within 5 mm; 2. retracting posterior boundary of level II to front edge of levator scapula muscle, and descending the upper boundary to transverse process of C2 vertebra only for OSCC; 3. including posterior third of thyroglossal muscle or anterior edge of sternocleidomastoid muscle; 4. sparing level Va in case of only level II involvement; 5. including upper area of the thyroid cartilage plate in case of level Ib LN(+)/ENE (+); 6. sparing level VIIa is considered.

CONCLUSION

This is the first description of LN topographic spread patterns for OSCC/OPSCC. Modified CTV for prophylactic irradiation was proposed to spare the organs at risk and minimize adverse effects.

The role of the soft palate dose regarding normal tissue toxicities in older adults with head and neck cancer undergoing definitive radiotherapy

PURPOSE

The number of older adults with head and neck squamous cell carcinoma (HNSCC) is continuously increasing. Older HNSCC patients may be more vulnerable to radiotherapy-related toxicities, so that extrapolation of available normal tissue complication probability (NTCP) models to this population may not be appropriate. Hence, we aimed to investigate the correlation between organ at risk (OAR) doses and chronic toxicities in older patients with HNSCC undergoing definitive radiotherapy.

METHODS

Patients treated with definitive radiotherapy, either alone or with concomitant systemic treatment, between 2009 and 2019 in a large tertiary cancer center were eligible for this analysis. OARs were contoured based on international consensus guidelines, and EQD2 doses using α/ß values of 3 Gy for late effects were calculated based on the radiation treatment plans. Treatment-related toxicities were graded according to Common Terminology Criteria for Adverse Events version 5.0. Logistic regression analyses were carried out, and NTCP models were developed and internally validated using the bootstrapping method.

RESULTS

A total of 180 patients with a median age of 73 years fulfilled the inclusion criteria and were analyzed. Seventy-three patients developed chronic moderate xerostomia (grade 2), 34 moderate dysgeusia (grade 2), and 59 moderate-to-severe (grade 2-3) dysphagia after definitive radiotherapy. The soft palate dose was significantly associated with all analyzed toxicities (xerostomia: OR = 1.028, dysgeusia: OR = 1.022, dysphagia: OR = 1.027) in the multivariable regression. The superior pharyngeal constrictor muscle was also significantly related to chronic dysphagia (OR = 1.030). Consecutively developed and internally validated NTCP models were predictive for the analyzed toxicities (optimism-corrected AUCs after bootstrapping: AUCxerostomia=0.64, AUCdysgeusia=0.60, AUCdysphagia=0.64).

CONCLUSIONS

Our data suggest that the dose to the soft palate is associated with chronic moderate xerostomia, moderate dysgeusia and moderate-to-severe dysphagia in older HNSCC patients undergoing definitive radiotherapy. If validated in external studies, efforts should be undertaken to reduce the soft palate dose in these patients.

Acute Diabetes-Related Complications in Patients Receiving Chemoradiotherapy for Head and Neck Cancer

Patients with cancer and diabetes face unique challenges. Limited data are available on diabetes management in patients undergoing concurrent chemoradiotherapy (CCRT), a curative intent anticancer therapy commonly associated with glucocorticoid administration, weight fluctuations and enteral feeds. This retrospective case-control study examined the real-world incidence of acute diabetes-related complications in patients with head and neck cancer receiving CCRT, along with the impact of diabetes on CCRT tolerance and outcomes.

METHODS

Consecutive patients with head and neck squamous cell or nasopharyngeal cancer who underwent definitive or adjuvant CCRT between 2010 and 2019 at two large cancer centers in Australia were included. Clinicopathological characteristics, treatment complications and outcomes were collected from medical records.

RESULTS

Of 282 patients who received CCRT, 29 (10.3%) had pre-existing type 2 diabetes. None had type 1 diabetes. The majority (74.5%) required enteral feeding. A higher proportion of patients with diabetes required admission to a high-dependency or intensive care unit (17.2 versus 4.0%, p = 0.003). This difference was driven by the group who required insulin at baseline (n = 5), of which four (80.0%) were admitted to a high-dependency unit with diabetes-related complications, and three (60.0%) required omission of at least one cycle of chemotherapy.

CONCLUSIONS

Patients with diabetes requiring insulin have a high risk of acute life-threatening diabetes-related complications while receiving CCRT. We recommend multidisciplinary management involving a diabetes specialist, educator, dietitian, and pharmacist, in collaboration with the cancer care team, to better avoid these complications.

Prospects for online adaptive radiation therapy (ART) for head and neck cancer

BACKGROUND

The aim of the present study is to examine the impact of kV-CBCT-based online adaptive radiation therapy (ART) on dosimetric parameters in comparison to image-guided-radiotherapy (IGRT) in consecutive patients with tumors in the head and neck region from a prospective registry.

METHODS

The study comprises all consecutive patients with tumors in the head and neck area who were treated with kV-CBCT-based online ART or IGRT-modus at the linear-accelerator ETHOS™. As a measure of effectiveness, the equivalent-uniform-dose was calculated for the CTV (EUDCTV) and organs-at-risk (EUDOAR) and normalized to the prescribed dose. As an important determinant for the need of ART the interfractional shifts of anatomic landmarks related to the tongue were analyzed and compared to the intrafractional shifts. The latter determine the performance of the adapted dose distribution on the verification CBCT2 postadaptation.

RESULTS

Altogether 59 consecutive patients with tumors in the head-and-neck-area were treated from 01.12.2021 to 31.01.2023. Ten of all 59 patients (10/59; 16.9%) received at least one phase within a treatment course with ART. Of 46 fractions in the adaptive mode, irradiation was conducted in 65.2% of fractions with the adaptive-plan, the scheduled-plan in the remaining. The dispersion of the distributions of EUDCTV-values from the 46 dose fractions differed significantly between the scheduled and adaptive plans (Ansari-Bradley-Test, p = 0.0158). Thus, the 2.5th percentile of the EUDCTV-values by the adaptive plans amounted 97.1% (95% CI 96.6-99.5%) and by the scheduled plans 78.1% (95% CI 61.8-88.7%). While the EUDCTV for the accumulated dose distributions stayed above 95% at PTV-margins of ≥ 3 mm for all 8 analyzed treatment phases the scheduled plans did for margins ≥ 5 mm. The intrafractional anatomic shifts of all 8 measured anatomic landmarks were smaller than the interfractional with overall median values of 8.5 mm and 5.5 mm (p < 0.0001 for five and p < 0.05 for all parameters, pairwise comparisons, signed-rank-test). The EUDOAR-values for the larynx and the parotid gland were significantly lower for the adaptive compared with the scheduled plans (Wilcoxon-test, p < 0.001).

CONCLUSIONS

The mobile tongue and tongue base showed considerable interfractional variations. While PTV-margins of 5 mm were sufficient for IGRT, ART showed the potential of decreasing PTV-margins and spare dose to the organs-at-risk.

Radiation-induced long-term dysphagia in survivors of head and neck cancer and association with dose-volume parameters

BACKGROUND

Although dysphagia is a common side effect after radiotherapy (RT) of head and neck cancer (HNC), data on long-term dysphagia is scarce. We aimed to 1) compare radiation dose parameters in HNC survivors with and without dysphagia, 2) investigate factors associated with long-term dysphagia and its possible impact on health-related quality of life (HRQoL), and 3) investigate how our data agree with existing NTCP models.

METHODS

This cross-sectional study conducted in 2018-2020, included HNC survivors treated in 2007-2013. Participants attended a one-day examination in hospital and filled in patient questionnaires. Dysphagia was measured with the EORTC QLQ-H&N35 swallowing scale. Toxicity was scored with CTCAE v.4. We contoured swallowing organs at risk (SWOAR) on RT plans, calculated dose-volume histograms (DVHs), performed logistic regression analyses and tested our data in established NTCP models.

RESULTS

Of the 239 participants, 75 (31%) reported dysphagia. Compared to survivors without dysphagia, this group had reduced HRQoL and the DVHs for infrahyoid SWOAR were significantly shifted to the right. Long-term dysphagia was associated with age (OR 1.07, 95% CI 1.03-1.10), female sex (OR 2.75, 95% CI 1.45-5.21), and mean dose to middle pharyngeal constrictor muscle (MD-MPCM) (OR 1.06, 95% CI 1.03-1.09). NTCP models overall underestimated the risk of long-term dysphagia.

CONCLUSIONS

Long-term dysphagia was associated with higher age, being female, and high MD-MPCM. Doses to distally located SWOAR seemed to be risk factors. Existing NTCP models do not sufficiently predict long-term dysphagia. Further efforts are needed to reduce the prevalence and consequences of this late effect.

Delineation of the "Oropharyngeal Mucosa" and Limiting its Dose in Head and Neck Cancer Patients Spares the Oropharynx Without Compromising Target Coverage

OBJECTIVES

Radiation-induced oropharyngeal injury is a dose-limiting toxicity in head and neck cancer patients. Delineation of the "oropharyngeal mucosa" and limiting its dose to spare the oropharynx was investigated.

METHODS

In this retrospective study, computed tomography imaging from eight patients with previously untreated head and neck cancer was employed. An adaptive contouring brush within the planning software Monaco was used to create an air cavity within the oropharynx, and then the air cavity was expanded uniformly 2 mm to create the "oropharyngeal mucosa". Three plans were independently generated for each patient: Plan1: dose constraint was applied for the oropharynx; Plan2: dose constraints were applied for the oropharynx and the "oropharyngeal mucosa"; Plan3: dose constraint was applied for the "oropharyngeal mucosa". T-tests were used to compare the dosimetry variables.

RESULTS

All plans had adequate target coverage and there were no statistical differences among plans. The mean dose, D30%, D45%, D50%, D85%, D90%, D95%, D100%, V25 Gy, V30 Gy, V35 Gy, V40 Gy, and V45 Gy of the oropharynx and "oropharyngeal mucosa" in Plan1 were significantly higher than those in Plan2 and Plan3. There were no significant differences between Plan2 and Plan3. There were no significant differences in the dosimetric parameters of any other organs at risk.

CONCLUSION

Delineation of the "oropharyngeal mucosa" and limiting its dose should be an easy and effective method to spare the oropharynx.