Dysphagia and trismus after concomitant chemo-Intensity-Modulated Radiation Therapy (chemo-IMRT) in advanced head and neck cancer; dose–effect relationships for swallowing and mastication structures

The impact of different timing of mouth opening exercises on trismus in postoperative radiotherapy patients with oral cancer

OBJECTIVE

To compare the effects of starting mouth opening exercises at two different times on trismus in postoperative radiotherapy patients with oral cancer.

METHODS

Through a prospective randomized controlled trial, purposive sampling was used to select 76 patients undergoing postoperative radiotherapy for oral cancer from March 2023 to January 2024 at the Department of Oral and Maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. Patients were randomly divided into an experimental group (n = 38) and a control group (n = 38) using a random number table at a ratio of 1:1. The experimental group began mouth opening exercises in the second week after surgery (before radiotherapy), while the control group began in the fourth week after surgery (at the start of radiotherapy). The primary outcome measure was maximum interincisal opening (MIO). Secondary outcome measures included pain visual analog scale (VAS) scores and quality of life scores (UW-QOL), assessed at baseline, the second week post-surgery (before radiotherapy), the fourth week post-surgery (at the start of radiotherapy), the ninth week post-surgery (end of radiotherapy), and the twelfth week post-surgery (three weeks after the end of radiotherapy).

RESULTS

A total of 72 patients completed all assessments, with 36 in each group, resulting in an overall sample attrition rate of 5.26 % (less than 15 %). There were no statistically significant differences in general demographic and clinical characteristics between the two groups. Repeated measures ANOVA showed significant differences in MIO, VAS, and UW-QOL scores between groups, over time, and in group-time interactions (P < 0.001). From the fourth week post-surgery (at the start of radiotherapy), the experimental group had significantly higher MIO (P < 0.001), significantly lower VAS scores (P < 0.001), and significantly higher UW-QOL scores (P < 0.001) compared to the control group. These differences persisted at subsequent assessment points.

CONCLUSION

Initiating mouth opening exercises in the second week post-surgery (before radiotherapy) can significantly improve mouth opening, reduce pain, and enhance the quality of life in postoperative radiotherapy patients with oral cancer. This provides important evidence for clinical practice, although further research is needed to verify the long-term effects.

Dysphagia After Total Laryngectomy: An Exploratory Study and Clinical Phase II Rehabilitation Trial with the Novel Swallowing Exercise Aid (SEA 2.0)

The aims of this exploratory study and clinical phase II trial were to assess the specific nature and extent of dysphagia in laryngectomized patients with self-reported dysphagia, and its rehabilitation potential using the novel Swallowing Exercise Aid (SEA 2.0). Twenty laryngectomized patients participated in a six-week exercise program with the SEA 2.0. Exercises consisted of Chin Tuck Against Resistance (CTAR), Jaw Opening Against Resistance (JOAR), and Effortful Swallow Against Resistance, conducted three times per day. Swallowing was assessed at baseline (T0), six (T1) and 14 (T2) weeks, consisting of patient-reported outcomes, BMI, videofluoroscopy, swallowing capacity, and muscle strength measurements. Dysphagia significantly impacts quality of life, with impaired swallowing speed and bolus propulsion as main reported issues. Subjective dysphagia parameters, swallowing capacity, and pharyngeal residue clearance were reduced, but BMI was normal. Muscle and tongue strength were within normal ranges. All participants managed to use the SEA 2.0. Adherence was 95%. At T1, subjective swallowing parameters (MDADI and EAT-10) showed clinically relevant improvements. Objectively, CTAR and JOAR strength increased with 27.4 and 20.1 Newton, respectively. Also, swallowing capacity (from 2.4 g/s to 3.8 g/s) and pharyngeal residue clearance improved. At T2, results were slightly lower than at T1, but still better than at baseline. Dysphagia in laryngectomized patients affects quality of life, but swallowing can be improved with a six-week rehabilitation program using the novel SEA 2.0. Adherence was excellent and several subjective and objective swallowing parameters improved.

Generalized root agenesis in permanent dentition of a young adolescent patient with rhabdomyosarcoma: a case report

BACKGROUND

Parameningeal rhabdomyosarcoma (PM-RMS) is a rare and aggressive soft tissue malignancy that primarily occurs in the head and neck region. The standard treatment approach for RMS involves a multimodal therapy regimen, which includes surgery, chemotherapy, and radiotherapy. However, the routine use of radiotherapy and chemotherapy in young patients with RMS in the head and neck region can lead to adverse effects on dental development and thereby, pose a challenge in planning dental intervention.

CASE PRESENTATION

This case report outlines the dental and facial developmental consequences in a 13-year-old child, who received chemo-radiotherapeutic intervention at the age of 7 years for the management of PM-RMS. Following treatment, the child exhibited significant dental complications, including arrested root growth and restricted mouth opening.

CONCLUSIONS

This case highlights the necessity for interdisciplinary collaboration between oncologists, dentists, and other healthcare professionals to mitigate the adverse effects on dental health and overall quality of life in patients undergoing chemo-radiotherapy for rhabdomyosarcoma.

Assessment of peripheral dose as a function of distance and depth from cobalt-60 beam in water phantom using TLD-100

BACKGROUND

Innovations in cancer treatment have contributed to the improved survival rate of cancer patients. The cancer survival rates have been growing and nearly two third of those survivors have been exposed to clinical radiation during their treatment. The study of long-term radiation effects, especially secondary cancer induction, has become increasingly important. An accurate assessment of out-of-field/peripheral dose (PDs) is necessary to estimate the risk of second cancer after radiotherapy and the damage to the organs at risk surrounding the planning target volume. This study was designed to measure the PDs as a function of dose, distances, and depths from Telecobalt-60 (Co-60) beam in water phantom using thermoluminescent dosimeter-100 (TLD-100).

METHODS

The PDs were measured for Co-60 beam at specified depths of 0 cm (surface), 5 cm, 10 cm, and 15 cm outside the radiation beam at distances of 5, 10, and 13 cm away from the radiation field edge using TLD-100 (G1 cards) as detectors. These calibrated cards were placed on the acrylic disc in circular tracks. The radiation dose of 2000 mGy of Co-60 beam was applied inside 10 × 10 cm2 field size at constant source to surface distance (SSD) of 80 cm.

RESULTS

The results showed maximum and minimum PDs at surface and 5 cm depth respectively at all distances from the radiation field edge. Dose distributions out of the field edge with respect to distance were isotropic. The decrease in PDs at 5 cm depth was due to dominant forward scattering of Co-60 gamma rays. The increase in PDs beyond 5 cm depth was due to increase in the irradiated volume, increase in penumbra, increase in source to axis distance (SAD), and increase in field size due to inverse square factor.

CONCLUSION

It is concluded that the PDs depends upon depth and distance from the radiation field edge. All the measurements show PDs in the homogenous medium (water); therefore, it estimates absorbed dose to the organ at risk (OAR) adjacent to cancer tissues/planning target volume (PTV). It is suggested that PDs can be minimized by using the SAD technique, as this technique controls sources of scattered radiation like inverse square factor and effect of penumbra up-to some extent.

Impact of Radiation on Dysphagia-Related Structures: A Dosimetric and Clinical Comparative Analysis of Three-Dimensional Conformal Radiotherapy (3D-CRT) and Intensity-Modulated Radiation Therapy (IMRT) Techniques in Patients With Head and Neck Cancer

Introduction Head and neck squamous cell carcinoma (HNSCC) is a significant health concern in India, with around one million new cases annually. The prevalence of HNSCC is notably high in Asia, especially in India, due to habits like tobacco chewing, betel nut usage, and alcohol consumption. Treatment typically involves a combination of surgery, radiation, chemotherapy, and biological therapy, aiming for tumor control while preserving function and quality of life. However, survivors often face long-term side effects like difficulty swallowing, leading to complications such as aspiration pneumonia. Intensity-modulated radiotherapy (IMRT) has shown promise in improving outcomes by sparing critical swallowing structures. Efforts to minimize radiation-related dysphagia are crucial for enhancing patients' quality of life post-treatment. Our study focuses on examining dosimetric parameters associated with dysphagia aspiration, alongside evaluating dysphagia grades in both treatment groups using the RTOG scale. Material and methods Patients with histologically confirmed non-metastatic head and neck carcinomas were included in our study in November 2018-April 2020. A total of 56 patients were taken into our study with 28 in each arm. They underwent radical radiotherapy (RT) with a total dose of 66-70 Gy, with or without concurrent chemotherapy, meeting specific inclusion criteria and excluding those receiving reirradiation or with distant metastasis. Patients were divided into two groups: Group I received three-dimensional conformal radiotherapy (3D-CRT), and Group II received IMRT. Treatment planning involved immobilization, CT imaging, delineation of target volumes and organs at risk, and contouring of swallowing structures. Dose-volume histogram parameters (mean dose, maximum dose, V30, V70, V80, D50, and D80) were used to assess mean dose to swallowing structures outside the planning target volume (PTV), with a mean dose constraint of 50 Gy. Dysphagia was evaluated using the RTOG criteria at baseline, during treatment, and six months post-treatment. Statistical analysis was performed using SPSS, with significance set at p < 0.05. Results In our study, the mean age at presentation differed slightly between the IMRT and 3D-CRT arms: 58 years versus 55 years, respectively. A higher proportion of patients in both arms experienced symptoms for three to six months, with 53.6% in 3D-CRT and 42.9% in IMRT. Stage distribution varied, with IV being most common in 3D-CRT and stage II in IMRT. Approximately 56% of patients in both groups had a history of smoking. Significant differences were observed in spinal cord dose between 3DCRT and IMRT techniques (p < 0.001). Similarly, a significant difference was found in the mean dose received by dysphagia aspiration-related structures (DARSs) between the 3D-CRT and IMRT arms (p = 0.04). Patients in the IMRT arm exhibited superior dysphagia grades compared to those in the 3D-CRT arm, with statistical significance observed in the third month (p = 0.008) and sixth month (p = 0.048). Conclusion Our study found a notable decrease in the mean DARS dose and reduced dysphagia severity at three and six months in the IMRT group compared to the 3D-CRT group. However, due to the diverse study population, establishing a definitive correlation between the DARS dose and dysphagia severity was challenging. Future large-scale studies are needed to validate these findings for improved preservation of DARS structures.

Automatic IMRT treatment planning through fluence prediction and plan fine-tuning for nasopharyngeal carcinoma

BACKGROUND

At present, the implementation of intensity-modulated radiation therapy (IMRT) treatment planning for geometrically complex nasopharyngeal carcinoma (NPC) through manual trial-and-error fashion presents challenges to the improvement of planning efficiency and the obtaining of high-consistency plan quality. This paper aims to propose an automatic IMRT plan generation method through fluence prediction and further plan fine-tuning for patients with NPC and evaluates the planning efficiency and plan quality.

METHODS

A total of 38 patients with NPC treated with nine-beam IMRT were enrolled in this study and automatically re-planned with the proposed method. A trained deep learning model was employed to generate static field fluence maps for each patient with 3D computed tomography images and structure contours as input. Automatic IMRT treatment planning was achieved by using its generated dose with slight tightening for further plan fine-tuning. Lastly, the plan quality was compared between automatic plans and clinical plans.

RESULTS

The average time for automatic plan generation was less than 4 min, including fluence maps prediction with a python script and automated plan tuning with a C# script. Compared with clinical plans, automatic plans showed better conformity and homogeneity for planning target volumes (PTVs) except for the conformity of PTV-1. Meanwhile, the dosimetric metrics for most organs at risk (OARs) were ameliorated in the automatic plan, especially Dmax of the brainstem and spinal cord, and Dmean of the left and right parotid glands significantly decreased (P < 0.05).

CONCLUSION

We have successfully implemented an automatic IMRT plan generation method for patients with NPC. This method shows high planning efficiency and comparable or superior plan quality than clinical plans. The qualitative results before and after the plan fine-tuning indicates that further optimization using dose objectives generated by predicted fluence maps is crucial to obtain high-quality automatic plans.

Feasibility of Achieving Dose Constraints for Dysphagia Aspiration-Related Structures and Its Clinical Significance in Intensity-Modulated Radiotherapy Planning of Head and Neck Cancer

Introduction Dysphagia is commonly seen in patients with head and neck cancers after undergoing chemoradiotherapy and is often under-reported and also not given clinical importance. The quality of life of the patients can be significantly improved if the required dose constraints to the dysphagia aspiration-related structures (DARS) are achieved. The present study was conducted in order to determine the feasibility of achieving the dose constraints to DARS between the standard intensity-modulated radiotherapy (st-IMRT) arm and the dysphagia-optimized IMRT (do-IMRT) arm. Material and methods Sixty patients with head and neck cancer were recruited and randomized into two groups: In one group called the st-IMRT, constraints were not given to DARS, and in the other group called the do-IMRT, constraints were given to DARS. Treatment was given in the form of chemoradiation with a dose of 70 Gy in 35 fractions by IMRT technique, over seven weeks, 2 Gy per fraction along with weekly concurrent Cisplatin (35 mg/m2) in both the groups. Step and shoot IMRT setup was used for planning, and the system used for planning was Eclipse 13.6 (Varian Medical System, Inc., Palo Alto, CA, US); progressive resolution optimizer algorithm was used for optimization, and Anisotropic Analytical Algorithm algorithm was used for dose calculation. Truebeam was used for treatment delivery. DARS dosimetric parameters assessed were Dmean, V30, V50, V60, V70, D50, and D80. Radiation-induced toxicities to the skin, mucosa, larynx, salivary gland, and dysphagia and hematological toxicities were assessed in between both the groups during and after radiotherapy up to six months based on Common Terminology Criteria for Adverse Effects v5.0. p-values were calculated using the unpaired T-test. Results In the cohort of 60 patients with head and neck cancers, 95% were males. Dosimetric parameters of the planning target volume (PTV) were compared but were not found to be significant. In the dosimetry of the organs at risk, a p-value of some structures was found to be significant although the doses received were well within the tolerable limits in both arms. DARS dosimetry V60 and V70 of the inferior constrictor muscle was found to be statistically significant (p=0.01 and 0.008, respectively). V60 and V70 of larynx were also statistically significant (p=0.009 and 0.000, respectively). V70 and D50 of cricopharyngeus were found to be statistically significant (p=0.01 and 0.03, respectively), V30 and V60 for combined pharyngeal constrictor muscles were found to be statistically significant (p=0.02 and 0.01), and lastly, V60 for combined DARS was also significant (p=0.004). Post-treatment 33.3% of patients in the st-IMRT arm required Ryle's tube placement. No grade 4 toxicities were seen in either arm regarding hematological toxicities, acute or chronic radiation-induced toxicities. In site-wise comparison of doses, the p-value was not found to be significant in patients with oropharyngeal and oral cavity carcinomas but was found to be statistically significant in the larynx and hypopharynx subsites. Conclusion The feasibility of achieving dose constraints to the DARS was seen in cases of laryngeal and hypopharyngeal cancers where the constrictor muscles were at a distance from the PTV. Further, the feasibility of achieving dose constraints may be seen in lower-dose prescriptions either in postoperative cases or in low-risk clinical target volume nodal volumes.

Primary and adjuvant intensity-modulated radiotherapy in oropharyngeal carcinoma patients from a single institution

BACKGROUND

To retrospectively access outcome, adverse events and prognostic factors in oropharyngeal carcinoma (OPC) patients treated with intensity-modulated radiotherapy (IMRT).

METHODS

Ninety-eight OPC patients were treated between 2000 and 2015. Thirty-three patients received definitive and 65 adjuvant radiotherapy. Seventy-one percent had simultaneous chemotherapy. Patients were systematically followed up (mean 114 months, range 19-197 months). Statistical analysis used Kaplan-Meier method, Cox regression analysis, and log-rank test. Adverse events were classified according to common toxicity criteria version (CTCAE) 4.03.

RESULTS

The 1-, 5-, and 10-year overall survival rates in the adjuvant vs. definitive cohort were 90.8% vs. 66.7%, 67.4% vs. 33.1%, and 57.7% vs. 16.5%. Survival in the adjuvant cohort was significantly longer than in the definitive cohort (P < 0.00005). Patients <65 years had a significantly longer survival than older patients. Locoregional tumor control rates after 1-, 5-, and 10 years in the adjuvant vs. definitive cohort were 90.2% vs. 66.7%, 82.2% vs 45.4%, and 72.1% vs. 30.3%. Locoregional tumor control in the adjuvant cohort was significantly longer than in the definite cohort (P < 0.005). Distant metastases were diagnosed in 20.4% of all patients. Most patients had mild CTCAE grade 1 and 2 adverse events and mild late adverse events including xerostomia, dysphagia, and lymphedema.

CONCLUSION

Intensity-modulated radiotherapy for OPC is an important part of the treatment algorithm alone and in particular after surgery while the additional benefits of chemotherapy might be age dependent. Despite advanced tumor stages, nearly half of our patients were alive in the long term. The majority of patients had relatively mild chronic adverse events.

Toxicities and clinical outcome of adjuvant dysphagia optimized versus standard intensity-modulated radiotherapy for post-operative oral cavity cancers: A prospective comparative study

BACKGROUND

We prospectively assessed acute and late toxicity in post-operative oral cavity squamous cell carcinoma (PO-OCSCC) treated with adjuvant dysphagia optimized intensity-modulated radiotherapy (Do-IMRT) versus standard IMRT (S-IMRT).

MATERIAL AND METHODS

Fifty-six patients of PO-SCC without indications of concurrent chemotherapy were alternatively allocated to adjuvant Do-IMRT (n = 28) versus S-IMRT (n = 28) arms. High- and low-risk planning target volume received 60 and 54 Gy, respectively, in 30 fractions over 6 weeks. Dysphagia aspiration-related structures (DARS) were contoured in both arms. While dosimetric constraints were given in Do-IMRT arm, doses to DARS were only observed without dose constraints in S-IMRT arm. Acute and late toxicity were assessed by common terminology criteria for adverse events (CTCAE) v5.0 and RTOG criteria, respectively.

RESULTS

The primary site of disease was buccal mucosa (64% vs. 53%) and oral tongue (21% vs. 32%), in Do-IMRT and S-IMRT, respectively. The mean doses to DARS was significantly less with Do-IMRT (all p < 0.001) as compared to S-IMRT. Median follow-up was 24.2 months. Grade ≥2 oral pain was less in the Do-IMRT arm (50% vs. 78.6%, p = 0.05). Grade ≥2 late dysphagia at 2 years were significantly less in Do-IMRT arm (0% vs. 17.9%, p = 0.016). Two-year locoregional control was 89.2% in Do-IMRT and 78.5% in S-IMRT (p = 0.261).

CONCLUSION

DARS can be spared in PO-OCSCC patients treated with Do-IMRT without compromising coverage of the target volumes. Limiting doses to DARS leads to lesser acute and late toxicity without compromising locoregional control.

Role of sarcopenia on survival and treatment-related toxicity in head and neck cancer: a narrative review of current evidence and future perspectives

PURPOSE

The purpose of this article is to provide an up-to-date summary of sarcopenia and its clinical implications for patients with head and neck cancer (HNC).

METHODS

We conducted a literature review of recent studies investigating the prevalence of sarcopenia in HNC patients, its detection using MRI or CT scans, and its association with clinical outcomes such as disease-free and overall survival time, radiotherapy-related side effects, cisplatin toxicity, and surgical complications.

RESULTS

Sarcopenia, characterized by low skeletal muscle mass (SMM), is a prevalent condition in HNC patients and can be effectively detected using routine MRI or CT scans. Low SMM in HNC patients is associated with increased risks of shorter disease-free and overall survival times, as well as radiotherapy-related side effects such as mucositis, dysphagia, and xerostomia. In addition, cisplatin toxicity is more severe in HNC patients with low SMM, leading to higher dose-limiting toxicity and treatment interruptions. Low SMM may also predict higher risks of surgical complications in head and neck surgery. Identifying sarcopenic patients can aid physicians in better riskstratifying HNC patients for therapeutic or nutritional interventions to improve clinical outcomes.

CONCLUSIONS

Sarcopenia is a significant concern for HNC patients and can impact their clinical outcomes. Routine MRI or CT scans can effectively detect low SMM in HNC patients. Identifying sarcopenic patients can aid physicians in better risk-stratifying HNC patients for therapeutic or nutritional interventions to improve clinical outcomes. Further research is needed to explore the potential of interventions to mitigate the negative effects of sarcopenia in HNC patients.

Longitudinal changes in swallowing function after surgery and proactive swallowing therapy for oral cancer

BACKGROUND

This study aimed to describe and explore the longitudinal changes in swallowing function among patients with oral cancer who underwent surgery and proactive swallowing therapy from baseline to 1-year postoperation.

METHODS

We retrospectively studied 118 patients over a 4.5-year duration. Swallowing functional assessment including 10-item Eating Assessment Tool (EAT-10), Functional Oral Intake Scale (FOIS), M. D. Anderson Dysphagia Inventory, and Modified Barium Swallow Impairment Profile (MBSImP™) was performed at baseline, 1-month, 6-month, and 1-year postoperatively.

RESULTS

All swallowing parameters worsened 1-month postoperation. EAT-10, FOIS, and MBSImP™ oral and pharyngeal impairment scores improved significantly compared with 1-month postoperation at 6 months. Other swallowing parameters, except for weight, did not differ significantly from baseline at 6 months. The rate of tube-feeding dependency was 11.5% and 5.6% at 1 and 6 months postoperation, respectively.

CONCLUSIONS

Periodic swallowing functional assessments help delineate the longitudinal changes in swallowing functional outcomes.

Trismus surgery and microsurgical reconstruction after oral cancer treatment

INTRODUCTION

Trismus after oral cancer is frequent, with scarce evidence of surgical release treatment in these patients.

OBJECTIVES

The objective of this study is to determine the results of trismus release and free flap reconstruction after oral cancer treatment, establish immediate and long-term results, and detect factors that influence outcome.

MATERIALS AND METHODS

A retrospective study was performed. Preoperative, intraoperative, and follow-up interincisal distances were measured. The intraoperative, long-term gain, and postoperative loss were calculated. Analysis of the long-term results with the preoperative and intraoperative variables was performed.

RESULTS

Surgical release immediately increased the interincisal distance by 29.25 mm. Sixty-six percent of this gain was lost due to trismus recurrence, giving a long-term interincisal gain of 9.90 mm. Worse results were observed in patients with previous high-stage tumors, maxillectomies, skin resections, and previous radiotherapy. The were no significant differences in the results depending on the type of release or reconstruction performed, with the exception of the reconstruction with the sural flap, which presented worse results. Patients with trismus of ≤10 mm could have more range for improvement after this surgery.

CONCLUSIONS

The results of this surgery are moderate in the long term due to high trismus recurrence in spite of aggressive treatment.

Investigation of the Effect of Radiotherapy Dose on Chewing and Swallowing Structures in Head and Neck Cancer Patients Treated with Concomitant Chemoradiotherapy

Intensity-modulated radiotherapy (IMRT) is a treatment method that is used in the treatment of head and neck cancers. Impairment of chewing and swallowing functions in the early and late periods of radiotherapy is frequent. Therefore, revealing the dose-effect relationship is important. The main purpose of this study is to investigate the dose-effect relationship between chewing and swallowing structures objectively via a standardized videofluoroscopy protocol. The study included 35 participants treated with chemo-IMRT. A videofluoroscopic swallowing study (VFSS) was performed before IMRT, and 3 and 6 months after IMRT. VFSS results were scored according to the Modified Barium Swallow Impairment Profile (MBSImP) and the Penetration-Aspiration Scale (PAS). Maximum interincisor mouth opening, body mass index (BMI), and Functional Oral Intake Scale levels were determined in these cases. The quality of life of participants was evaluated. There was a significant increase in PAS and MBSImP scores and a significant decrease in BMI scores of the patients after treatment. Xerotomy and sticky saliva complaints increased after treatment. The dose to the mastication muscles (> 40 Gy) and the temporomandibular joint (> 46 Gy) were found to be associated with a decrease in BMI; the dose to the superior pharyngeal constructor muscle (> 58 Gy) was found to be associated with pharyngeal stripping wave. The presence of aspiration was associated with the inferior pharyngeal constructor muscle, glottic larynx, supraglottic larynx, and upper esophageal sphincter. Important findings to emerge from this study include detected toxic dose limits. These findings may guide physicians to minimize the side effects of IMRT.

Longitudinal functional outcomes and late effects of radiation following treatment of nasopharyngeal carcinoma: secondary analysis of a prospective cohort study

BACKGROUND

The study objectives were: provide longitudinal data on upper aerodigestive tract function and late complications following IMRT for nasopharyngeal carcinoma, and elucidate factors that might predict a worse outcome. The hypotheses were: (1) Despite advances such as IMRT, radiation will cause significant functional decline and late complications that often progress or arise years after treatment. (2) Larger radiation volume will be associated with poorer outcomes.

METHODS

Longitudinal, observational cohort study of nasopharyngeal carcinoma patients with retrospective analysis of prospectively collected, population-based data. Late sequelae and validated measures of overall performance, speech, and swallowing were documented pre-treatment and 3,6,12, 24, 36 and ≥ 60-months post-treatment.

RESULTS

Forty-two patients treated curatively with radiation (N = 9) or chemoradiation (N = 33) were followed for a median 74 months. Functional outcomes showed an initial nadir at 3 months associated with acute effects of treatment, followed by initial recovery. There was subsequent functional decline years post-treatment with advancing dysphagia/aspiration, trismus, muscle spasm, and hypoglossal nerve palsy. Univariable regression analysis revealed that increasing high-dose radiation volumes (PTV 70 Gy) were associated with increased likelihood of less than solid diet (Performance Status Scale (PSS)-Normalcy of Diet score < 50; p = 0.04), and reduced PSS-Understandability of Speech (p = 0.005). The probability of poor outcome increased with time. Eleven percent of patients were tube feed dependent at ≥ 5 years.

CONCLUSIONS

Despite improvements in radiation delivery, late effects of radiation remain common. Higher radiation volumes are associated with poorer outcomes that worsen over time.

Photobiomodulation therapy in management of cancer therapy-induced side effects: WALT position paper 2022

Disclaimer

This article is based on recommendations from the 12th WALT Congress, Nice, October 3-6, 2018, and a follow-up review of the existing data and the clinical observations of an international multidisciplinary panel of clinicians and researchers with expertise in the area of supportive care in cancer and/or PBM clinical application and dosimetry. This article is informational in nature. As with all clinical materials, this paper should be used with a clear understanding that continued research and practice could result in new insights and recommendations. The review reflects the collective opinion and, as such, does not necessarily represent the opinion of any individual author. In no event shall the authors be liable for any decision made or action taken in reliance on the proposed protocols.

Objective

This position paper reviews the potential prophylactic and therapeutic effects of photobiomodulation (PBM) on side effects of cancer therapy, including chemotherapy (CT), radiation therapy (RT), and hematopoietic stem cell transplantation (HSCT).

Background

There is a considerable body of evidence supporting the efficacy of PBM for preventing oral mucositis (OM) in patients undergoing RT for head and neck cancer (HNC), CT, or HSCT. This could enhance patients’ quality of life, adherence to the prescribed cancer therapy, and treatment outcomes while reducing the cost of cancer care.

Methods

A literature review on PBM effectiveness and dosimetry considerations for managing certain complications of cancer therapy were conducted. A systematic review was conducted when numerous randomized controlled trials were available. Results were presented and discussed at an international consensus meeting at the World Association of photobiomoduLation Therapy (WALT) meeting in 2018 that included world expert oncologists, radiation oncologists, oral oncologists, and oral medicine professionals, physicists, engineers, and oncology researchers. The potential mechanism of action of PBM and evidence of PBM efficacy through reported outcomes for individual indications were assessed.

Results

There is a large body of evidence demonstrating the efficacy of PBM for preventing OM in certain cancer patient populations, as recently outlined by the Multinational Association for Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). Building on these, the WALT group outlines evidence and prescribed PBM treatment parameters for prophylactic and therapeutic use in supportive care for radiodermatitis, dysphagia, xerostomia, dysgeusia, trismus, mucosal and bone necrosis, lymphedema, hand-foot syndrome, alopecia, oral and dermatologic chronic graft-versus-host disease, voice/speech alterations, peripheral neuropathy, and late fibrosis amongst cancer survivors.

Conclusions

There is robust evidence for using PBM to prevent and treat a broad range of complications in cancer care. Specific clinical practice guidelines or evidence-based expert consensus recommendations are provided. These recommendations are aimed at improving the clinical utilization of PBM therapy in supportive cancer care and promoting research in this field. It is anticipated these guidelines will be revised periodically.

Comparison of Dosimetric Parameters in Dysphagia Aspiration-Related Structures and Clinical Correlation in Head and Neck Cancer Patients Treated With Radiotherapy

Introduction

Chemoradiotherapy plays a major role in the treatment of head and neck cancer (HNC). Persistent dysphagia following primary chemoradiotherapy for head and neck cancers can have a devastating effect on a patient’s quality of life. Many studies have shown that the dosimetric sparing of critical structures which were included in swallowing such as the pharyngeal constrictor muscle and larynx can provide improved functional outcomes and better quality of life. However, there are no current randomized studies confirming the benefits of such swallowing-sparing strategies. The aim is to evaluate late dysphagia after chemoradiotherapy for head and neck cancer and to examine its correlation with clinical and dosimetric parameters.

Materials and methods

The period of this prospective study was from November 2018 to March 2020. Patients were divided randomly in 1:1 ratio into two groups, group 1 and group 2, each with 25 patients. Group 1 was planned by three-dimensional conformal radiotherapy (3D-CRT) technique and group 2 was planned by intensity-modulated radiotherapy technique (IMRT) technique. Treatment was delivered after approval of radiotherapy plan. To evaluate the dose to dysphagia aspiration-related structures (DARS), these structures were contoured and dose-volume histograms were generated. Various dosimetric parameters of DARS were evaluated. Swallowing status was clinically evaluated based on the Radiation Therapy Oncology Group and the Common Terminology Criteria for Adverse Events, version 5.

Results

A significant advantage was seen with intensity-modulated radiotherapy technique (IMRT) in comparison to three-dimensional conformal radiotherapy (3D-CRT) in terms of mean dose delivered to the pharyngeal constrictor muscles (66.03 Gy vs 68.77 Gy, p=0.003). The mean dose delivered to the combined dysphagia/aspiration-related structures (DARS) was statistically significantly lower in IMRT compared to 3D-CRT (66.15 Gy vs. 70.09 Gy, p<0.001). Other dose-volumes were also reduced in IMRT group (V30: {98.64% vs. 99.88%, p=0.05}; V50: {90.49% vs. 99.02%, p=0.0002}; V60: {83.92% vs. 95.04, p=0.0002}; D50: {70 Gy vs. 71.16 Gy, p=0.001); and D80: {61.18 Gy vs. 67.39 Gy, p=0.01}. Futhermore, the clinical worsening of dysphagia was less common in IMRT group (48% vs. 80%, p=0.039).

Conclusion

IMRT can reduce the high-dose volumes received by the DARS receiving high doses by sparing these structures through optimization. This may provide a significant additional benefit that could improve dysphagia and hence the quality of life of patients with head and neck cancer.

A predictive nomogram for trismus after radiotherapy for head and neck cancer

BACKGROUND

The aim of this study is to develop a prediction model for trismus (maximal interincisal distance equal to or less than 35 millimeters) based on a multivariable analysis of dosimetric and clinical factors METHODS: The Maximum inter-incisal opening (MIO) of HNC patients who underwent radiotherapy (RT) +/- concurrent chemotherapy with radical intent was prospectively measured prior to RT (baseline) and 6 months post-RT. The outcome variable is trismus. The potential risk factors (clinical and dosimetric) were first screened by univariate analysis and then by multivariate analysis. At the end of this process, we used the features identified as relevant to fit a logistic regression model and calculate the probability of observed trismus during the 6-month follow-up after radiation treatment.

RESULTS

One hundred and four consecutive patients were included (mean age 63 years, range 25-87), 68 were males, 36 females. In the univariate analysis, the MIO at baseline, as an independent variable, and several V_doses of different masticatory structures were found as significant. Additionally, using a bivariate model, a feature selection process was performed. Finally, we considered as best performing model the MIO at baseline and V₄₂ at Masseter Muscle. The area under curve (AUC) of Receiver Operating Characteristic (ROC) curve value of 0,8255 (95% CI 0.74-0.9). The Hosmer and Lemeshow goodness-of-fit test, used to calibrate our model, is non-significant.

CONCLUSIONS

A prediction nomogram was developed to assess trismus risk in planning process. An external validation of the model is required to apply it for current clinical use.

The Impact of Postoperative Radiotherapy on Dietary Function of Head and Neck Cancer Patients after Pharyngoesophageal Reconstruction with Free Jejunal Flap

This study investigated the impact of postoperative radiotherapy (PORT) on dietary function in patients who underwent pharyngoesophageal defect reconstruction using a free jejunal flap. A retrospective chart review of 36 patients who underwent circumferential pharyngoesophageal defect reconstruction using a free jejunal flap was performed. The European Organization for the Research and Treatment of Cancer head and neck cancer module questionnaire was used. Five items related to dietary function were selected and analyzed for changes in scores before and after PORT. Both the PORT and non-PORT groups showed improved dietary function before surgery, and no significant changes were noted at 3 and 12 months postoperatively. Repeated measures ANOVA showed that PORT had no significant impact on dietary function. In univariate analysis, no variable was a significant predictor of the score at 12 months, postoperatively. Previous radiotherapy and neck dissection had a close statistically significant relation. The multivariate analysis showed that neoadjuvant chemotherapy, previous radiotherapy, and neck dissection were significant predictors of the score at 12 months, postoperatively. PORT did not show a significant effect on the 12 months postoperative score. Free jejunal flap is an effective pharyngoesophageal defect reconstruction method that does not cause any dietary function disruption after PORT.

Predictors of severe dysphagia following radiotherapy for head and neck cancer

OBJECTIVE

To investigate if severe dysphagia following radiotherapy for head and neck cancer (HNC) could be predicted by patient and tumor characteristics, feeding tube use, weight factors, jaw opening function, and saliva secretion.

METHODS

Data was collected from 94 HNC patients 6 to 36 months post radiotherapy. Swallowing function was assessed by videofluroscopy (VFS). Severe dysphagia was defined by Penetration Aspiration Scale (PAS) as PAS≥5 or a total score ≤60 on the M. D. Anderson Dysphagia Inventory (MDADI).

RESULTS

Thirty-three patients (35%) had PAS ≥5 and 19 (20%) a MDADI ≤60, that is, presented with severe dysphagia. Univariable logistic regression analysis (UVA) gave that tumor of the tonsil, overweight at time of VFS and each unit increase in Body Mass Index (BMI) predicted less risk of PAS ≥5. Dependency of feeding tube at time of VFS and each month's continued use and weight loss ≥7.5% since treatment to time of VFS predicted increased risk of PAS ≥5. Predictive variables from the UVA of PAS ≥5 (tumor of the tonsil, overweight, and total duration of feeding tube), were analyzed by multivariate logistic regression analysis. All retained power as independent predictors. UVA for MDADI showed that use of feeding tube at time of VFS predicted MDADI ≤60 with the risk increasing each month. Each increasing unit of BMI decreased risk of MDADI ≤60.

CONCLUSION

Long time users of feeding tube and higher weight-loss are at risk of severe dysphagia. This makes collaboration between professionals working with dysphagia an important step in detecting severe dysphagia.Level of Evidence: 3.

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

Objectives

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

Materials and Methods

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

Results

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

Conclusions

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

Early-Stage Glottic Squamous Cell Carcinoma in the Era of Image-Guided Radiotherapy

Early-stage squamous cell cancer (SCC) of the glottis has a good prognosis. Therefore, patients have long survival outcomes and may potentially suffer from late toxicities of radiotherapy. Radiotherapy with a conventional parallel-opposed-pair or anterior-oblique beam arrangements for stage 1 and 2 glottic SCC have field borders that traditionally cover the entire larynx, exposing organs-at-risk (e.g. carotid arteries, contralateral vocal cord, contralateral arytenoid and inferior pharyngeal constrictor muscles) to high radiation doses. The potential long-term risk of cerebrovascular events has attracted much attention to the dose that carotid arteries receive. Swallow and respiratory motion of laryngeal structures has been an important factor that previously limited reduction of the radiation treatment volume. Motion has been evaluated using multiple imaging modalities and this information has been used to calculate PTV margins for generation of more limited target volumes. This review discusses the current literature surrounding dose-effect relationships for various organs-at-risk and the late toxicities that are associated with them. This article also reviews the currently available data and effects of laryngeal motions on dosimetry to the primary target. We also review the current limitations and benefits of a more targeted approach of radiotherapy for early-stage glottic SCCs and the evolution of CT-based IGRT and MR-guided radiotherapy techniques that may facilitate a shift away from a conventional 3D-conformal radiotherapy approach.

Association of Trismus With Quality of Life and Swallowing in Survivors of Head and Neck Cancer

OBJECTIVE

We aim to (1) determine the prevalence and predictors of trismus and (2) examine the relationship of trismus, swallowing dysfunction, and quality of life (QOL) in survivors of head and neck cancer (HNC).

STUDY DESIGN

Case series with chart review.

SETTING

Multidisciplinary HNC survivorship clinic.

METHODS

Data on trismus and patient-reported outcomes were obtained from survivors of HNC between December 2016 and October 2019. Trismus was defined as a maximum interincisal opening ≤35 mm. QOL and swallowing dysfunction were measured with the University of Washington Quality of Life questionnaire and EAT-10 (Eating Assessment Tool-10), respectively. Linear regressions were applied to investigate the relationship of trismus with QOL and swallowing dysfunction.

RESULTS

Of the 237 survivors, 22.78% (n = 54) had trismus. Advanced stage of cancer (stage III/IV vs Tis-II, P = .002) and treatment (nonsurgical and surgery + adjuvant treatment vs surgery only, P = .006) were correlated with a higher prevalence of trismus. After controlling for cancer stage and treatment type, EAT-10 scores for survivors with trismus were 9.342 (95% CI, 6.262-12.423; P < .0001) higher than those without trismus. The University of Washington Quality of Life Physical and Social-Emotional subscales for patients with trismus were 14.088 (95% CI, 9.042-19.134; P < .0001) and 10.470 (95% CI, 4.793-16.147; P = .0003) lower than those without trismus, respectively.

CONCLUSION

Trismus is a common, treatment-related consequence and is associated with increased symptoms of dysphagia and decreased QOL. Early detection and management of trismus in survivors of HNC are essential to optimize QOL and reduce morbidity.

[State of art of photobiomodulation in the management of radiotherapy adverse events: Indications and level of evidence]

PURPOSE

To evaluate the current and potential indications of photobiomodulation (PBM) and their level of evidence in the prevention or management of radiation therapy-related side effects.

MATERIALS AND METHODS

The Embase, Medline/PubMed, Cochrane, EBSCO, Scopus, and LILACS databases were systematically reviewed to include and analyze publications of clinical studies that have assessed PBM in the prevention or management of radiotherapy-related side effects. The keywords used were "photobiomodulation"; "low level laser therapy"; "acute oral mucositis"; "acute dysphagia"; "acute radiation dermatitis"; "lymphedema"; "xerostomia"; "hyposalivation"; "trismus"; "bone necrosis"; "osteoradionecrosis"; and "radiation induced fibrosis". Prospective studies were included, whereas retrospective cohorts and non-original articles were excluded from the analysis.

RESULTS

PBM in the red or infrared spectrum has demonstrated efficacy in randomized controlled trials in the prevention and management of radiotherapy-related side effects, especially acute oral mucositis, acute radiation dermatitis, and upper extremity lymphedema. The level of evidence associated with PBM was heterogeneous, but overall was still moderate. The main shortcomings were the diversity and lack of detail in treatment protocols, which could have compromised efficiency and reproducibility of PBM results.

CONCLUSION

The published data suggest that PBM may be considered as a full-fledged supportive care for patients treated with radiotherapy, or at least in the setting of a therapeutic clinical trial. However, until strong evidence has been published on its long-term safety, the use of PBM should be considered with caution, specifically when applied near areas with proven or potential tumors. The patient should be informed of the theoretical benefits and risks of PBM in order to obtain his informed consent before treatment.

Specimen oriented intraoperative margin assessment in oral cavity and oropharyngeal squamous cell carcinoma

OBJECTIVE

Evaluate the oncologic outcomes and cost analysis of transitioning to a specimen oriented intraoperative margin assessment protocol from a tumour bed sampling protocol in oral cavity (OCSCC) and oropharyngeal squamous cell carcinoma (OPSCC).

STUDY DESIGN

Retrospective case series and subsequent prospective cohort study SETTING: Tertiary care academic teaching hospital SUBJECTS AND METHODS: Retrospective case series of all institutional T1-T2 OCSCC or OPSCC treated with primary surgery between January 1st 2009 - December 31st 2014. Kaplan-Meier survival estimates with log rank tests were used to compare patients based on final margin status. Cost analysis was performed for escalation of therapy due to positive final margins. Following introduction of a specimen derived margin protocol, successive prospective cohort study of T1-T4 OCSCC or OPSCC treated with primary surgery from January 1st 2017 - December 31st 2018. Analysis and comparison of both protocols included review of intraoperative margins, final pathology and treatment cost.

RESULTS

Analysis of our intra-operative tumour bed frozen section protocol revealed 15 of 116 (12.9%) patients had positive final pathology margins, resulting in post-operative escalation of therapy for 14/15 patients in the form of re-resection (7/14), radiation therapy (6/14) and chemoradiotherapy (1/14). One other patient with positive final margins received escalated therapy for additional negative prognostic factors. Recurrence free survival at 3 years was 88.4 and 50.7% for negative and positive final margins respectively (p = 0.048). Implementation of a specimen oriented frozen section protocol resulted in 1 of 111 patients (0.9%) having positive final pathology margins, a statistically significant decrease (p < 0.001). Utilizing our specimen oriented protocol, there was an absolute risk reduction for having a final positive margin of 12.0% and relative risk reduction of 93.0%. Estimated cost avoidance applying the specimen oriented protocol to our previous cohort was $412,052.812017 CAD.

CONCLUSION

Implementation of a specimen oriented intraoperative margin protocol provides a statistically significant decrease in final positive margins. This change in protocol leads to decreased patient morbidity by avoiding therapy escalation attributable only to positive margins, and avoids the economic costs of these treatments.

Dysphagia, trismus and speech impairment following radiation-based treatment for advanced stage oropharyngeal carcinoma: a one-year prospective evaluation

OBJECTIVE

The objective was to assess swallowing, mouth opening and speech function during the first year after radiation-based treatment (RT(+)) after introduction of a dedicated preventive rehabilitation program for stage III-IV oropharyngeal carcinoma (OPC).

METHODS

Swallowing, mouth opening and speech function were collected before and at six- and twelve-month follow-up after RT(+) for OPC as part of ongoing prospective assessments by speech-language pathologists .

RESULTS

Objective and patient-perceived function deteriorated until 6 months and improved until 12 months after treatment, but did not return to baseline levels with 25%, 20% and 58% of the patients with objective dysphagia, trismus and speech problems, respectively. Feeding tube dependency and pneumonia prevalence was low.

CONCLUSION

Despite successful implementation, a substantial proportion of patients still experience functional limitations after RT(+) for OPC, suggesting room for improvement of the current rehabilitation program. Pretreatment sarcopenia seems associated with worse functional outcomes and might be a relevant new target for rehabilitation strategies.

Asymptomatic swallowing disorders may be present in individuals with laryngeal and hypopharyngeal cancer treated with chemo-radiotherapy

PURPOSE

Patients with advanced laryngeal and hypopharyngeal cancer are often treated with chemo-radiotherapy to avoid total laryngectomy. Subclinical swallowing disorders could be present in these patients even though patients do not complain of any symptoms. We sought to evaluate the impact of chemoradiation on swallowing and quality of life.

METHODS

We studied 21 patients undergoing chemo-radiotherapy for advanced laryngeal and hypopharyngeal cancer. All patients were tumor-free and none reported symptoms related to dysphagia during follow-up or showed altered routine screening tests (EAT-10) to detect it. Swallowing functions were assessed using volume-viscosity swallow test (V-VST) and fiberoptic endoscopic evaluation of swallowing (FEES). Quality of life was assessed with the EORT-H&N35, and SWAL-QOL scales.

RESULTS

Frequent alterations in swallowing efficacy (100%) and safety (85.5%) were detected with V-VST and FEES. Quality-of-life scales showed a reduction in their scores between 12 and 17%, mainly in the areas of symptoms.

CONCLUSION

Swallowing disorders are common after chemo-radiotherapy, even in patients who do not clinically manifest these disorders, contributing to a decrease in patients' quality of life. FEES and V-VST are useful procedures to detect asymptomatic swallowing disorders.

Brachytherapy of the head and neck: An University of California Los Angeles guide to morbidity reduction

The head and neck (H&N) region is among the most intricate and functional part of our anatomy. Major functional nerves and blood vessels with importance that affect the entire body emanate from the base of skull. Brachytherapy plays an important role as a single modality therapy in early cancer of the lip and oral cavity and a supplemental role in the pharynx or in advanced or recurrent disease. Morbidity in the H&N is intensely personal and disabling. Its avoidance is critical in determining the success or failure of a treatment program, and it is essential to preservation of quality of life. This article summarizes the current literature regarding morbidity related to H&N brachytherapy to aid patients and physicians to achieve optimal outcomes.

Evaluation of Carbon Ion Radiation-Induced Trismus in Head and Neck Tumors Using Dose-Volume Histograms

Simple Summary

Patients who receive carbon ion radiotherapy (C-ion RT) for tumors near the temporomandibular joint are likely to experience trismus, a condition characterized by reduced jaw opening. However, the relationship between the dose of carbon ion and the onset of trismus remains unclear. Therefore, we conducted a subgroup analysis of a prospective observational study to understand the relationship between the dose of carbon ion and the occurrence of trismus. Of 35 patients included in the study, six developed grade 2 trismus, and the median onset time was 12 months. The affected muscles included masticatory muscles and the coronoid process. Our findings suggest better treatment planning, such as dose optimization, to minimize the occurrence of muscle-related adverse effects associated with C-ion RT.

Abstract

Carbon ion radiotherapy (C-ion RT) provides a highly localized deposition of energy that can increase radiation doses to tumors while minimizing irradiation of adjacent normal tissues. For tumors located near the temporomandibular joint, C-ion RT-induced trismus may occur. However, the relationship between the carbon ion dose and the onset of trismus is unclear. In this prospective observational study, we assessed the trismus/carbon ion dose relationship using dose−volume histograms in 35 patients who received C-ion RT in their head and neck regions between 2010 and 2014. Trismus was evaluated in patients according to the Common Terminology Criteria for Adverse Events, version 4.0. All patients were treated with 57.6 or 64.0 Gy (relative biological effectiveness (RBE)) in 16 fractions, and the median follow-up time was 57 months. Grade 2 trismus was observed in six patients. The median onset time was 12 months. At maximum radiation doses, all masticatory muscles and coronoid processes, particularly the masseter muscle, were significantly different (p = 0.003). The contouring of the masseter muscle and coronoid process requires different treatment planning. The maximum radiation doses of the coronoid process can be proposed as a guideline for treatment planning, considering the ease of contouring in C-ion RT.

Temporomandibular Joint Dislocation following Pterygomasseteric Myotomy and Coronoidectomy in the Management of Postradiation Trismus

Supplemental Digital Content is available in the text.

Trismus is a known complication following treatment of oral and oropharyngeal cancers, with radiation therapy reported as a known risk factor for its development. The prevention of trismus after radiation therapy is hard to achieve, with no clear benefit of early prophylactic rehabilitation. Pterygomasseteric myotomy and coronoidectomy are well described procedures in the management of extra-articular trismus. Herein, we present 2 cases of temporomandibular joint dislocation as a cautionary tale of the potential risk for temporomandibular joint dislocation and need for closed reduction and maxillomandibular fixation.

Deep learning vs. atlas-based models for fast auto-segmentation of the masticatory muscles on head and neck CT images

BACKGROUND

Impaired function of masticatory muscles will lead to trismus. Routine delineation of these muscles during planning may improve dose tracking and facilitate dose reduction resulting in decreased radiation-related trismus. This study aimed to compare a deep learning model with a commercial atlas-based model for fast auto-segmentation of the masticatory muscles on head and neck computed tomography (CT) images.

MATERIAL AND METHODS

Paired masseter (M), temporalis (T), medial and lateral pterygoid (MP, LP) muscles were manually segmented on 56 CT images. CT images were randomly divided into training (n = 27) and validation (n = 29) cohorts. Two methods were used for automatic delineation of masticatory muscles (MMs): Deep learning auto-segmentation (DLAS) and atlas-based auto-segmentation (ABAS). The automatic algorithms were evaluated using Dice similarity coefficient (DSC), recall, precision, Hausdorff distance (HD), HD95, and mean surface distance (MSD). A consolidated score was calculated by normalizing the metrics against interobserver variability and averaging over all patients. Differences in dose (∆Dose) to MMs for DLAS and ABAS segmentations were assessed. A paired t-test was used to compare the geometric and dosimetric difference between DLAS and ABAS methods.

RESULTS

DLAS outperformed ABAS in delineating all MMs (p < 0.05). The DLAS mean DSC for M, T, MP, and LP ranged from 0.83 ± 0.03 to 0.89 ± 0.02, the ABAS mean DSC ranged from 0.79 ± 0.05 to 0.85 ± 0.04. The mean value for recall, HD, HD95, MSD also improved with DLAS for auto-segmentation. Interobserver variation revealed the highest variability in DSC and MSD for both T and MP, and the highest scores were achieved for T by both automatic algorithms. With few exceptions, the mean ∆D98%, ∆D95%, ∆D50%, and ∆D2% for all structures were below 10% for DLAS and ABAS and had no detectable statistical difference (P > 0.05). DLAS based contours had dose endpoints more closely matched with that of the manually segmented when compared with ABAS.

CONCLUSIONS

DLAS auto-segmentation of masticatory muscles for the head and neck radiotherapy had improved segmentation accuracy compared with ABAS with no qualitative difference in dosimetric endpoints compared to manually segmented contours.

Precision toxicity correlates of tumor spatial proximity to organs at risk in cancer patients receiving intensity-modulated radiotherapy

PURPOSE

Using a 200 Head and Neck cancer (HNC) patient cohort, we employ patient similarity based on tumor location, volume, and proximity to organs at risk to predict radiation-associated dysphagia (RAD) in a new patient receiving intensity modulated radiation therapy (IMRT).

MATERIAL AND METHODS

All patients were treated using curative-intent IMRT. Anatomical features were extracted from contrast-enhanced tomography scans acquired pre-treatment. Patient similarity was computed using a topological similarity measure, which allowed for the prediction of normal tissues' mean doses. We performed feature selection and clustering, and used the resulting groups of patients to forecast RAD. We used Logistic Regression (LG) cross-validation to assess the potential toxicity risk of these groupings.

RESULTS

Out of 200 patients, 34 patients were recorded as having RAD. Patient clusters were significantly correlated with RAD (p < .0001). The area under the receiver-operator curve (AUC) using pre-established, baseline features gave a predictive accuracy of 0.79, while the addition of our cluster labels improved accuracy to 0.84.

CONCLUSION

Our results show that spatial information available pre-treatment can be used to robustly identify groups of RAD high-risk patients. We identify feature sets that considerably improve toxicity risk prediction beyond what is possible using baseline features. Our results also suggest that similarity-based predicted mean doses to organs can be used as valid predictors of risk to organs.

Dose-volume correlates of the prevalence of patient-reported trismus in long-term survivorship after oropharyngeal IMRT: A cross-sectional dosimetric analysis

PURPOSE

To ascertain the dose-toxicity relationship for the prevalence of self-reported trismus in long-term survivors after intensity-modulated radiotherapy (IMRT) for oropharyngeal carcinoma (OPC).

MATERIALS AND METHODS

Self-reported mouth opening was ascertained prospectively via a cross-sectional survey of OPC survivors using the intraoral finger-test. RT dose-volume histograms (DVHs) were generated for the following masticatory regions of interest: medial pterygoid, lateral pterygoid, and masseter muscles which were designated as ipsilateral or contralateral to the primary tumor. Trismus was defined as self-reported mouth opening of <3 finger-widths. Recursive partitioning analysis (RPA) was performed to identify the dose-volume thresholds associated with late trismus.

RESULTS

At a median follow-up time of 72 months (95% CI 68-74), 168 of the 587 (29%) survey respondents reported late trismus. Multivariate analysis demonstrated a significant association between late trismus and the following clinical variables: tonsillar primary site, advanced T stage, or higher total RT dose. RPA showed DVH-derived ipsilateral lateral pterygoid (ILP) mean dose of 61 Gy and volume receiving 27 Gy of at least 98.6% were independently associated with late trismus. The association between the ILP dosimetric parameters and the prevalence of late trismus was maintained after adjustment for clinical variables.

CONCLUSION

The integral dose of IMRT results in unavoidable low/intermediate dose to non-target masticatory muscles that is associated with increased prevalence of late trismus in OPC survivors. Whenever clinically and technically applicable, applying the proposed dosimetric constraints to the ILP (V27 <98.6 and D_mean <61 Gy) may reduce the prevalence of late trismus after IMRT for OPC patients.

Etiopathogenesis of Trismus in Patients With Head and Neck Cancer: An Exploratory Literature Review

Trismus refers to a person's inability to normally open his or her mouth. Trismus can occur as a symptom due to tumor ingrowth or it can occur postsurgical following the treatment for head and neck cancer. Radiation-induced trismus is also a relatively common oral complication. This review aimed at reviewing the etiopathogenesis of trismus in patients with head and neck cancer. Of the 16 publications included after final screening, of which one was a nonrandomized control trial, one a randomized control trial, 6 prospective cohort studies, and 8 retrospective cohort studies. Among them, 6 articles addressed the possible mechanism for trismus related to tumor ingrowth, 8 articles suggested the likely reason for trismus in patients who had undergone radiation therapy and 2 articles addressed the postsurgical cause for trismus. This review highlights the possible involvement of infratemporal fossa as a predetermining factor for developing trismus related to tumor extension. The molecular mechanism of radiation-induced fibrosis is well studied in the literature.

Temporomandibular disorders in head and neck cancers: Overview of specific mechanisms and management

Diagnosis classification system of Temporomandibular disorders (TMD) is based on the biopsychosocial model of pain. The pathogenesis is poorly understood, leading to difficulties in treating these multifactorial conditions. The predisposing factors are pathophysiological, psychological or structural processes that alter the masticatory system and lead to an increase in the risk of development of TMD. The purpose of this integrative review was then to point out the specific mechanisms of TMD in the oral oncologic context to optimize the TMJ functional results in the management of patients with oral oncologic conditions. We explored in this paper the role of Axis II assessment of the biopsychosocial model of pain, the involvement of mechanical concepts such as dental occlusion, mandibular condyle positioning and related-structures reconstruction, and the stomatognathic changes induced by radiation.

Predicting Swallowing Outcomes from Objective Videofluoroscopic Timing and Displacement Measures in Head and Neck Cancer Patients

Radiation therapy with or without chemotherapy compromises swallowing efficiency and safety in patients with head and neck cancer (HNC). The resulting dysphagia leads to overall morbidity, with altered diets, reduced nutritional intake, reduced quality of life, and potential interruption of curative cancer treatment. Despite well-documented radiation-related changes in swallowing physiology, scarce research exists on the potential clinical value for measurements of swallowing timing and displacement in this population. This study investigated the discriminatory value of quantitative timing and displacement parameters for the Functional Oral Intake Scale and Penetration Aspiration Scale scores using pre- and post-radiation videofluoroscopy data. Swallowtail Software Version 1 (Belldev Medical, Arlington Heights, IL) was used to obtain objective timing and displacement measurements from the pre- and post-radiation videofluoroscopy data for 31 patients who underwent radiation therapy, with or without chemotherapy, for head and neck cancer. The total pharyngeal transit time (BP2) (p < 0.000, r = 0.43) in pudding bolus trials and the maximal upper esophageal sphincter opening (PESMax/cm) (p = 0.001, r = 0.31) in thin bolus trials were discriminatory for Functional Oral Intake Scale (FOIS). Findings suggest that measurement of post-radiation changes using objective and quantitative parameters may offer some discriminatory value regarding future dysphagia risk and prognosis based on total pharyngeal transit time and degree of UES opening. In addition, the results suggest that different bolus types may offer different discriminatory values in HNC population, and that some timing and displacement variables may have discriminatory value for patients' diet levels independent from any aspiration risk.

Deglutition disorders as a consequence of head and neck cancer therapies: a systematic review and meta-analysis

PURPOSE

In this study, we aimed to estimate the frequency of deglutition disorders in patients pre- and post-treatment for head and neck cancer (HNC).

METHODS

Search strategies were developed for the following databases: LILACS, PubMed, SpeechBITE, LIVIVO, Web of Science, and Scopus. Additionally, the gray literature was searched using Google Scholar, OpenGrey, and ProQuest. Only studies that conducted an evaluation of deglutition before and after cancer treatment and had sufficient quantitative data were included. We conducted a proportion of random effects meta-analysis using R statistical software.

RESULTS

Seventeen studies were included. Aspiration showed a high frequency in the period less than 3 months post-treatment, with 28.6% (total sample = 229). Penetration of fluids above the vocal folds and reduced laryngeal elevation were more frequent in the period less than 6 months post-treatment.

CONCLUSION

The frequency of deglutition disorders and its complications, such as aspiration, appears to be higher in the immediate to 6-month post-treatment period in patients with HNC. The parameter pharyngeal residue continued to increase through the period analyzed.

Use of the Penetration-Aspiration Scale in Dysphagia Research: A Systematic Review

The penetration-aspiration scale (PAS) is an 8-point scale used to characterize the depth and response to airway invasion during videofluoroscopy. Though widely used in the field of deglutition, there is a lack of consensus regarding the statistical properties of the scale. In order to better understand the state of the literature and the statistical use of the PAS, a systematic review was undertaken to descriptively examine trends in statistical and reporting practices of the PAS since its inception. Online databases were searched for studies citing the original PAS article, which yielded 754 unique articles. Of these, 183 studies were included in the review. Results showed inconsistencies in the statistical use of the scale; 79 studies treated the PAS as ordinal, 71 as categorical, and 49 as interval. Ten types of categorizations were identified. Reporting of power analyses (9%), as well as inter- (26%) and intra-rater (17%) reliability, was uncommon. Among studies that administered multiple bolus volumes or consistencies, 55% reported PAS analyses at the participant/group level only. This review confirms the existence of discrepancies in the statistical treatment of the PAS. A lack of consensus among researchers limits comparisons between studies. The approach to handling this scale dictates the statistical tests used, potentially affecting results and interpretations. Consistent application of statistically sound approaches to PAS analyses is vital for the future of deglutition research.

Radiation-Induced Hypothyroidism After Radical Intensity Modulated Radiation Therapy for Oropharyngeal Carcinoma

PURPOSE

To evaluate 2 published normal tissue complication probability models for radiation-induced hypothyroidism (RHT) on a large cohort of oropharyngeal carcinoma (OPC) patients who were treated with intensity-modulated radiation therapy (IMRT).

METHODS AND MATERIALS

OPC patients treated with retrievable IMRT Digital Imaging and Communications in Medicine (DICOMs) data and available baseline and follow-up thyroid function tests were included. Mean dose (Dmean) to the thyroid gland (TG) and its volume were calculated. The study outcome was clinical HT at least 6 months after radiation therapy, which was defined as grade ≥2 HT per Common Terminology Criteria for Adverse Events grading system (symptomatic hypothyroidism that required thyroid replacement therapy). Regression analyses and Wilcoxon rank-sum test were used. Receiver operating characteristic curves and area under the curve for the fitted model were calculated.

RESULTS

In the study, 360 OPC patients were included. The median age was 58 years. Most tumors (51%) originated from the base of tongue. IMRT-split field was used in 95%, and median radiation therapy dose was 69.96 Gy. In the study, 233 patients (65%) developed clinical RHT that required thyroid replacement therapy. On multivariate analysis higher Dmean and smaller TG volume maintained the statistically significant association with the risk of clinical RHT (P < .0001). Dmean was significantly higher in patients with clinical RHT versus those without (50 vs 42 Gy, P < .0001). Patients with RHT had smaller TG volume compared with those without (11.8 compared with 12.8 mL, P < .0001). AUC of 0.72 and 0.66 were identified for fitted model versus for the applied Boomsma et al and Cella et al models, respectively.

CONCLUSIONS

Volume and Dmean of the TG are important predictors of clinical RHT and shall be integrated into normal tissue complication probability models for RHT. Dmean and thyroid volume should be considered during the IMRT plan optimization in OPC patients.

Identifying organs at risk for radiation-induced late dysphagia in head and neck cancer patients

Background and purpose

Dysphagia is a common, severe and dose-limiting toxicity after oncological treatment of head and neck cancer (HNC). This study aims to investigate relationships between radiation doses to structures involved in normal swallowing and patient-reported as well as clinically measured swallowing function in HNC patients after curative (chemo-) radiation therapy (RT) with focus on late effects.

Materials and methods

Patients (n = 90) with HNC curatively treated with RT ± chemotherapy in 2007-2015 were assessed for dysphagia post-treatment by telephone interview and videofluoroscopy (VFS). A study-specific symptom score was used to determine patient-reported dysphagia. The Penetration-Aspiration Scale (PAS) was applied to determine swallowing function by VFS (PAS ≥ 4/ ≥ 6 = moderate/severe dysphagia). Thirteen anatomical structures involved in normal swallowing were individually delineated on the patients' original planning CT scans and associated dose-volume histograms (DVHs) retrieved. Relationships between structure doses and late toxicity were investigated through univariable and multivariable logistic regression analysis (UVA/MVA) accounting for effects by relevant clinical factors.

Results

Median assessment time was 7 months post-RT (range: 5-34 months). Mean dose to the contralateral parotid gland and supraglottic larynx as well as maximum dose to the contralateral anterior digastric muscle predicted patient-reported dysphagia (AUC = 0.64-0.67). Mean dose to the pharyngeal constrictor muscle, the larynx, the supraglottic larynx and the epiglottis, as well as maximum dose to the contralateral submandibular gland predicted moderate and severe dysphagia by VFS (AUC = 0.71-0.80).

Conclusion

The patients in this cohort were consecutively identified pre-treatment, and were structurally approached and assessed for dysphagia after treatment at a specific time point. In addition to established dysphagia organs-at-risk (OARs), our data suggest that epiglottic and submandibular gland doses are important for swallowing function post-RT. Keeping DVH thresholds below V60 = 60% and V60 = 17%, respectively, may increase chances to reduce occurrence of severe late dysphagia. The results need to be externally validated in future studies.

Volumetric changes in pharyngeal structures following head and neck cancer chemoradiation therapy

OBJECTIVES/HYPOTHESIS

To determine the volumetric changes in pharyngeal structures in patients with head and neck squamous cell carcinoma (HNSCC) treated with curative chemoradiation therapy (CRT). Patients treated with CRT for esophageal carcinoma (EC), where pharyngeal structures were not part of the radiation treatment fields, were controlled for dysphagia-associated weight loss. We hypothesize that tissue volume alteration is a contributing factor of post-CRT dysphagia.

STUDY DESIGN

Case series.

METHODS

This study measured pre- and 1-year posttreatment volumes of the base of tongue (BOT), parapharyngeal spaces, posterior pharyngeal constrictors (PCs), and retropharyngeal space (RPS) in patients undergoing CRT for HNSCC or EC treated January 1, 2012 to December 31, 2015. All HNSCC patients were treated to doses of 66 to 70 Gy in 30 to 33 fractions using intensity-modulated radiotherapy techniques.

RESULTS

Our cohort included 49 HNSCC and 11 EC patients. Within the HNSCC cohort, the PCs volume increased 1.55 cm³ (95% confidence interval [CI]: 0.77 to 2.34 cm³ , P = .0002), RPS increased 1.22 cm³ (95% CI: 0.67 to 1.77 cm³ , P < .0001), and BOT decreased 2.29 cm³ (95% CI: -0.20 to 4.79 cm³ , P = .070). The EC cohort showed no significant volumetric changes for any anatomic space, with combined PCs and RPS volume changes statistically less than the HNSCC cohort (P = .031). There was no difference in mean body mass index reduction between groups (P = .10).

CONCLUSIONS

Volumetric changes following CRT may play a role in posttreatment dysphagia. Our findings support loss of physiologic function from posterior pharynx tissue thickening combined with reduced pharyngeal constriction capacity, and BOT atrophy secondary to radiation effects contribute to dysphagia.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:597-602, 2020.

Systematic review and meta-analysis of the impact of dosimetry to dysphagia and aspiration related structures

BACKGROUND

Technological advances in radiotherapy have allowed investigations into new methods to spare healthy tissue in those treated for head and neck cancer. This systematic review with meta-analysis demonstrates the effect that radiation has on swallowing.

METHODS

Selection and analysis of studies examining the effect of radiation to swallowing structures. A fixed effects meta-analysis calculated the pooled proportions for select outcomes of dysphagia, common across many studies.

RESULTS

The majority of the papers found a correlation between radiation dose to the swallowing structures and dysphagia, however a meta-analysis found the studies carried a significant degree of heterogeneity. The appraisal demonstrates the need for large-scale studies using a randomized design and instrumental dysphagia assessments.

CONCLUSIONS

Radiation dose to dysphagia and aspiration structures is correlated with incidence of dysphagia and aspiration. The variables in this population contribute to the heterogeneity within and cross studies and future studies should consider controlling for this.

Radiation dose to the masseter and medial pterygoid muscle in relation to trismus after chemoradiotherapy for advanced head and neck cancer

BACKGROUND

We studied the relationship between trismus (maximum interincisor opening [MIO] ≤35 mm) and the dose to the ipsilateral masseter muscle (iMM) and ipsilateral medial pterygoid muscle (iMPM).

METHODS

Pretreatment and post-treatment measurement of MIO at 13 weeks revealed 17% of trismus cases in 83 patients treated with chemoradiation and intensity-modulated radiation therapy. Logistic regression models were fitted with dose parameters of the iMM and iMPM and baseline MIO (bMIO). A risk classification tree was generated to obtain optimal cut-off values and risk groups.

RESULTS

Dose levels of iMM and iMPM were highly correlated due to proximity. Both iMPM and iMM dose parameters were predictive for trismus, especially mean dose and intermediate dose volume parameters. Adding bMIO, significantly improved Normal Tissue Complication Probability (NTCP) models. Optimal cutoffs were 58 Gy (mean dose iMPM), 22 Gy (mean dose iMM) and 46 mm (bMIO).

CONCLUSIONS

Both iMPM and iMM doses, as well as bMIO, are clinically relevant parameters for trismus prediction.

Trismus in patients with head and neck cancer and 5-year overall survival

BACKGROUND

Trismus is a common complication of radiotherapy for head and neck cancer but its impact on survival is unknown.

AIMS/OBJECTIVES

This prospective study evaluates the incidence of trismus in patients with head and neck cancer receiving radiotherapy and the impact of trismus on 5-year overall survival.

MATERIAL AND METHODS

Two hundred forty-four patients with head and neck cancer were included. All patients received instructions on jaw exercises and were evaluated before initiation of radiotherapy and at 2, 6, and 12 months after termination of radiotherapy.

RESULTS

One year after treatment 25% had a reduced maximum interincisal opening (MIO) of 13 mm or more as compared to the pretreatment MIO. Trismus was most prevalent in patients with oral and oropharyngeal cancer. A trend towards worse 5-year overall survival was seen among patients with trismus.

CONCLUSIONS

The trismus rate was approximately 30% at 12 months. Jaw exercises should primarily be offered to patients with oral and oropharyngeal cancer who are most likely to benefit. Further studies are required to investigate the effect of trismus on survival.

SIGNIFICANCE

This study identifies patients likely to benefit from jaw exercises and provides basis for further research on trismus and survival.

Use of a novel atlas for muscles of mastication to reduce inter observer variability in head and neck radiotherapy contouring

PURPOSE/OBJECTIVE(S)

Trismus is caused by injury to the masticatory muscles resulting from cancer or its treatment. Contouring these muscles to reduce dose and radiation related trismus can be problematic due to interobserver variability. This study aimed to evaluate the reduction in interobserver variability achievable with a new contouring atlas.

MATERIALS/METHODS

The atlas included: medial and lateral pterygoids (MP, LP), masseter (M) and temporalis (T) muscles, and the temporo-mandibular joint (TMJ). Seven clinicians delineated five paired structures on CT scans from 5 patients without the atlas. After ≥5 weeks, contouring was repeated using the atlas. Using contours generated by the clinicians on the same 5 CT scans as reference, dice similarity coefficient (DSC), mean distance-to-agreement (DTA) and centre of mass (COM) difference were compared with and without the atlas. Comparison was also performed split by training grade. Mean and standard deviation (SD) values were measured.

RESULTS

The atlas reduced interobserver variability for all structures. Mean DTA significantly improved for MP (p = 0.01), M (p < 0.01), T (p < 0.01) and TMJ (p < 0.01). Mean DTA improved using the atlas for the trainees across all muscles, with the largest reduction in variability observed for the T (4.3 ± 7.1 v 1.2 ± 0.4 mm, p = 0.06) and TMJ (2.1 ± 0.7 v 0.8 ± 0.3 mm, p < 0.01). Distance between the COM and interobserver variability reduced in all directions for MP and T.

CONCLUSION

A new atlas for contouring masticatory muscles during radiotherapy planning for head and neck cancer reduces interobserver variability and could be used as an educational tool.

Dosimetric evaluation of cobalt-60 teletherapy in advanced radiation oncology

Background

Recent investigations demonstrate a strong potential for cobalt-60 (Co-60)-based teletherapy. The influence of the lower energy and penetration of a cobalt-60 beam compared with linear accelerator beams is negligible for intensity-modulated radiotherapy.

Purpose

The aim of this research is to investigate source head fluence modulation in cobalt-60 teletherapy by using a three-dimensional (3D) physical compensator and secondary collimator jaw motion.

Materials and methods

The Oncentra treatment planning system was used to develop three hypothetical plans by secondary collimator jaw motion. A clinical MDS Nordion Equinox 80 cobalt-60 teletherapy unit was used to acquire conventional water phantom beam characteristics. Fluence modulation experiments were executed at 5·0 cm depth in a PTW universal intensity-modulated radiation therapy (IMRT) verification phantom using calibrated Gafchromic external beam therapy 2 (EBT2) and RTQA2-1010 film batches. Gafchromic EBT2 film was used to sample intensity maps generated by secondary collimator jaw motion, yet Gafchromic RTQA2-1010 film sampled maps from the 3D physical compensator. The solid-state drives used were 75·0 and 74·3 cm for the Gafchromic EBT2 and Gafchromic RTQA2-1010 film measurements.

Results

A 2D gamma index analysis was coded to compare EBT2 film measurements with Digital Imaging and Communications in Medicine data. This analysis was also used to verify film measurements versus Monte-Carlo simulations.

Conclusion

Lateral beam profiles generated from water phantom measurements were used to establish source head fluence modulation on the film measurements. The source head fluence of a cobalt-60 teletherapy beam could be modulated by secondary collimator jaw motion and using a 3D physical compensator.

Radiation-Associated Chronic Dysphagia Assessment by Flexible Endoscopic Evaluation of Swallowing (FEES) in Head and Neck Cancer Patients: Swallowing-Related Structures and Radiation Dose-Volume Effect

PURPOSE

We aimed to restore dose-volume parameters of swallowing-related structures (SRSs) by evaluating long-term swallowing dysfunctions after radiotherapy (RT) in head and neck cancer patients (HNCPs).

MATERIALS AND METHODS

Head and neck cancer patients whose pharyngeal region was involved in RT portal and treated with definitive RT/chemoradiotherapy (CRT) were included in the analyses. Patients underwent objective swallowing assessment by flexible endoscopic evaluation of swallowing (FEES). Volumes of SRSs that received 55 Gy (V₅₅) (mean dose [D_mean]) were evaluated according to the dose-volume histograms of each patient. For every SRS, optimal dose-volume cut-off values were determined by receiver operating characteristic curve analysis.

RESULTS

Fifty-five patients at a median 20 months (range, 12-26 months) after their treatments were evaluated. There was a strong negative correlation between FEES scores and dose-volume parameters of SRS ( r ⩽ -0.5, P < .0001). According to our results, middle pharyngeal constrictor (MPC) and inferior pharyngeal constrictor (IPC) had a D_mean > 57 Gy, base of tongue (BOT) D_mean > 50 Gy, supraglottic larynx (SGL) and glottic larynx (GL) D_mean > 55 Gy, and cervical esophagus (CE) D_mean > 45 Gy. MPC V₅₅ > 70%, IPC V₅₅ > 50%, BOT V₅₅ > 65%, CE V₅₅ > 40%, and SGL and GL V₅₅ > 50% were significant predictors for dysphagia.

CONCLUSION

It was found that dysphagia correlates strongly with dose-volume parameters of SRSs. IPC, SGL, and CE were found to be structures significantly associated with dysphagia.