How does radiotherapy impact swallowing function in nasopharynx and oropharynx cancer? Short-term results of a prospective study

Review of prophylactic swallowing interventions for head and neck cancer

BACKGROUND

Head and neck cancer treatment destroys nerves and/or organs associated with swallowing. Previous studies have investigated the efficacy of exercises for muscles used in swallowing before treatment in reducing disuse atrophy and delaying the occurrence of muscle fibrosis. However, the rehabilitation effects of training and the optimal intervention strategy are unknown.

OBJECTIVES

To establish evidence for the efficacy of prophylactic swallowing interventions in reducing aspiration and restoring oral intake in patients with head and neck cancer with dysphagia.

METHODS

We searched electronic databases (PubMed, Embase, Cochrane and MEDLINE) for studies published up to June 2021 reporting outcomes following prophylactic swallowing interventions in patients with head and neck cancer with dysphagia and the related influencing factors. The methodological quality of the literature was assessed using the Joanna Briggs Institute appraisal tools.

RESULTS

The search identified 1468 articles, and 13 studies were eventually included. Four categories involving 12 different swallowing interventions were classified. Regarding the descriptive analysis of the rehabilitation effects across all studies, in terms of oropharyngeal safety, five studies showed that swallowing interventions reduced the risk of aspiration, penetration or residue. In terms of oral intake and tube feeding dependence, four studies demonstrated reduced time to return to oral intake in the intervention group compared with the control group. In terms of intervention adherence, three studies showed that speech-language pathologist- and nurse-supervised training was a potential promoter of adherence, and five studies showed that the negative factors affecting adherence included pain, fatigue, forgetting, smoking, decreased exercise motivation, side effects of radiotherapy and distance to the rehabilitation site.

CONCLUSIONS

Preventive swallowing interventions may be effective at reducing aspiration, improving swallowing function, and restoring oral intake. However, due to the lack of standardization and consistency of interventions and measurement results, which prevented the production of a best practice guide, future rigorous methodological trials will be needed to determine the most effective interventions for maximizing exercise adherence over the long term.

Radiation-induced swallowing dysfunction in patients with head and neck cancer: A literature review

Swallowing dysfunction is a prevailing state following radiotherapy in patients with head and neck cancer. Following the advancement of cancer treatment in recent years, the survival rate of head and neck cancer has gradually increased. Simultaneously, patients with head and neck cancer suffer due to the long-duration and more prominent swallowing dysfunction states. Based on an extensive literature review, we aimed to explore the mechanisms, risk factors, and clinical evaluations of swallowing dysfunction and their related symptoms following radiotherapy. These include functional changes of the muscles, trismus, xerostomia, neuropathy, and lymphedema. When swallowing dysfunction occurs, patients usually seek medical help and are referred for rehabilitation therapy, such as muscle strengthening and tongue resistance exercise. Furthermore, clinicians should discuss with patients how and when to place the feeding tube. Only through detailed evaluation and management can swallowing dysfunction resolve and improve the quality of life of patients with head and neck cancer following radiotherapy.

Evaluating the safety of oral methylene blue during swallowing assessment: a systematic review

OBJECTIVE

Methylene blue (MB) is frequently administered during fiberoptic endoscopic evaluation of swallowing (FEES) to enhance visualization of pharyngeal bolus transit. However, the safety of MB is being questioned since serious adverse events (AEs) such as hemodynamic instability, hemolysis, and serotonin syndrome were reported. The aim of this study is a systematic analysis of the literature to obtain an evidence-based overview of AEs due to oral administration of MB and to determine its safety as a food dye during swallowing assessment.

METHODS

A systematic literature search was carried out in PubMed, Embase, and Cochrane Library. Two reviewers independently selected articles describing oral administration of MB as a main diagnostic/therapeutic intervention, dosage, and AEs. Expert opinions, conference papers, sample size < 10, and animal studies were excluded. Level of evidence of the included studies was determined.

RESULTS

A total of 2264 unduplicated articles were obtained. Seventeen studies met the inclusion criteria with 100% agreement between the two reviewers. Among these, twelve studies were randomized controlled trials. In a pooled population of 1902 patients receiving oral MB, three serious AEs were reported related to MB. Non-serious AEs showed a dose-related trend and were usually mild and self-limiting. A meta-analysis could not be performed as studies were methodologically too heterogeneous.

CONCLUSION

Serious AEs due to oral administration of MB are rare (n = 3, 0.16%). MB-related non-serious AEs are mild, self-limiting, and show a dose-related trend. These findings indicate that it is safe to use small amounts of MB as a food dye during swallowing examinations.

Incorporating dose-volume histogram parameters of swallowing organs at risk in a videofluoroscopy-based predictive model of radiation-induced dysphagia after head and neck cancer intensity-modulated radiation therapy

Purpose

To develop a videofluoroscopy-based predictive model of radiation-induced dysphagia (RID) by incorporating DVH parameters of swallowing organs at risk (SWOARs) in a machine learning analysis.

Methods

Videofluoroscopy (VF) was performed to assess the penetration-aspiration score (P/A) at baseline and at 6 and 12 months after RT. An RID predictive model was developed using dose to nine SWOARs and P/A-VF data at 6 and 12 months after treatment. A total of 72 dosimetric features for each patient were extracted from DVH and analyzed with linear support vector machine classification (SVC), logistic regression classification (LRC), and random forest classification (RFC).

Results

38 patients were evaluable. The relevance of SWOARs DVH features emerged both at 6 months (AUC 0.82 with SVC; 0.80 with LRC; and 0.83 with RFC) and at 12 months (AUC 0.85 with SVC; 0.82 with LRC; and 0.94 with RFC). The SWOARs and the corresponding features with the highest relevance at 6 months resulted as the base of tongue (V65 and D_mean), the superior (D_mean) and medium constrictor muscle (V45, V55; V65; D_mp; D_mean; D_max and D_min), and the parotid glands (D_mean and D_mp). On the contrary, the features with the highest relevance at 12 months were the medium (V55; D_min and D_mean) and inferior constrictor muscles (V55, V65 D_min and D_max), the glottis (V55 and D_max), the cricopharyngeal muscle (D_max), and the cervical esophagus (D_max).

Conclusion

We trained and cross-validated an RID predictive model with high discriminative ability at both 6 and 12 months after RT. We expect to improve the predictive power of this model by enlarging the number of training datasets.

Intensity-modulated radiation therapy in head-and-neck carcinomas: Potential beyond sparing the parotid glands

Head-and-neck cancer (HNC) is in close proximity to several critical structures. Intensity-modulated radiation therapy (IMRT) has the potential of generating highly conformal and concave dose distributions around complex target and is ideally suited for HNC treatment. Conventionally, the focus of IMRT for HNC patients has been on prevention of radiation-induced parotid dysfunction. In the present article, we review the potential of IMRT to reduce the risk of posttreatment aspiration and dysphagia and spare submandibular gland. We also discuss the impact of IMRT on overall survival and quality of life (QoL) for HNC patients. Small retrospective and prospective studies show that reducing dose to adjoining organs at risks is feasible and decreases the risk of posttreatment dysphagia and aspiration without compromising local control. IMRT is associated with improved QoL in several important domains including swallowing, dry mouth, sticky saliva, social eating, and opening of the mouth; however, improvement in global QoL is inconsistent. Delivery of IMRT for HNC is associated with improved survival at nasopharyngeal subsite. Small studies demonstrate improved treatment outcomes with swallowing-sparing IMRT. These results now need validation within the prospective multicenter randomized controlled trial setting.

Mechanisms of Impaired Swallowing on Thin Liquids Following Radiation Treatment for Oropharyngeal Cancer

Purpose Dysphagia is one of the most debilitating chronic symptoms experienced by patients who undergo radiation treatment for head and neck cancer. Despite the high prevalence of dysphagia in patients with head and neck cancer, we lack understanding of the specific changes in swallowing physiology that arise in the short-term following radiation therapy and how these changes impact the key functions of swallowing safety and efficiency. This study sought to identify pathophysiological mechanisms underlying impairments in swallowing safety and efficiency on thin liquids following (chemo)radiation for oropharyngeal cancer. Method Videofluoroscopic swallowing studies were completed in 12 male patients within 6 months following completion of (chemo)radiation and in 12 healthy male controls. To compare swallowing function and physiology between groups, we analyzed three discrete sips of 20% w/v thin liquid barium per participant. The videofluoroscopic swallowing study recordings were rated for swallowing safety, efficiency, timing parameters, and pixel-based measures of structural area or movement. Results The oropharyngeal cancer cohort displayed significantly higher frequencies of penetration-aspiration, incomplete laryngeal vestibule closure, prolonged time-to-laryngeal vestibule closure, and poor pharyngeal constriction. Incomplete or delayed laryngeal vestibule closure was associated with airway invasion, while poor pharyngeal constriction was associated with pharyngeal residue. Conclusions This study highlights the primary mechanisms behind impaired safety and efficiency of the swallow in patients following (chemo)radiation for oropharyngeal cancer.

Time as a factor during endoscopic assessment of swallowing: relevance in defining the score and severity of swallowing disorders

Time is a parameter of great interest in swallowing and can be considered in different ways to express severity during endoscopic evaluation. The objectives of this study are to evaluate how the severity of this score changes at different times of scoring and the interaction between residue persistence and airway invasion. Two experienced raters blindly evaluated 35 short clips of bolus transit that were recorded during endoscopic evaluations of 16 patients with dysphagia of differing aetiologies. The pooling score (p-score) and the Penetration Aspiration Scale (PAS) were detected after the first swallowing (T1) and after the fifth dry swallow (T5). For each task, the time needed to complete the clearing of the bolus (total time: TT) was blindly determined by the two raters and compared with the Functional Oral Intake Scale (FOIS) and Dysphagia Outcome and Severity Scale (DOSS) scales, previously detected.The inter-rater agreement between the 2 raters in scoring the p-score and PAS was good (ICC > 0.800) for T1 vs T1 and T1 vs T5, and in determining TT for each consistency (ICC > 0.9), with a Spearman’s Rho > 0.70 and > 0.90 respectively. A statistical correlation of the p-score total, TT and consistency with FOIS and DOSS was found. The p-score showed a good trade-off between sensitivity and specificity compared with the PAS aspiration and penetration scores. The time of scoring (T1 vs T5) is relevant in detecting severity of dysphagia during endoscopic evaluation. The time spent to clear residue is a useful parameter and is correlated with severity of dysphagia expressed by the p-score and with functional swallowing status in dysphagic patients. The p-score is correlated with the PAS score in detecting airway invasion.

Factors influencing non-adherence to radiotherapy: a retrospective audit of 1,548 patients from a tertiary cancer centre

Purpose:

To determine the frequency, factors and reasons of patient non-adherence to radiotherapy (RT) in a tertiary cancer centre.

Background:

Inadvertent treatment interruptions often lead to prolongation of planned treatment time. In the case of RT with a curative intent, prolongation of planned treatment has been associated with inferior clinical outcomes. Delay or prolongation of treatment is associated with a relative risk of local recurrence by up to 2% per day for specific malignancies. Thus, it is critical to understand key factors that influence non-adherence to RT.

Methods and Materials:

A retrospective observation audit was conducted comprising patients treated with radical, adjuvant or palliative RT at our centre from January 2018 to December 2018. Non-adherence was defined as premature permanent termination of planned treatment by the patient without recommendation or consultation from the treating clinician. All data were collected and analysed (retrospectively) with the help of Statistical Package for the Social Sciences (SPSS) version 22.

Results:

A total of 1,548 patients were included in the study of which 105 (6·7%) were non-adherent to planned RT. Of the total 105 patients, 44 (42%) were elderly (60 years and above). Treatment non-adherence was predominant in males (male:female = 1·85:1). More than 90% of non-adherent patients had stage III and IV cancer. A total of 77 patients (74%) out of 105 were more than 50 km away from our centre. A total of 66 (63%) out of 105 patients had completed more than 2 weeks of radiation (40% of planned RT) and then defaulted for radiation due to acute toxicities.

Conclusion:

Treatment adherence is a major factor in determining successful outcomes among cancer patients treated with RT. This study reveals several factors that contribute to non-adherence to treatment.

Functional evaluation of swallowing in patients with tongue cancer before and after surgery using high-speed continuous magnetic resonance imaging based on T2-weighted sequences

OBJECTIVES

The aim of this study was to determine the usefulness of evaluating the function of swallowing before and after surgery in patients with tongue cancer by using T2-weighted sequences of high-speed continuous magnetic resonance imaging (HSCMRI).

STUDY DESIGN

The imaging findings and related parameters on HSCMRI along with those on routine MRI examinations before and after surgery were examined in 19 patients with tongue cancer. In addition, changes in various parameters during 1 year after surgery were evaluated in 10 patients.

RESULTS

In most patients examined, the direction of flow to the esophagus could be seen on HSCMRI before and after surgery. Significant correlations were observed among 4 parameters and in the responses to a dysphagia questionnaire.

CONCLUSIONS

The results of the present study suggest that the dynamics of swallowing can be directly visualized on HSCMRI by using 4 parameters that permit the evaluation of changes before and after surgery, and this enables objective evaluation of patients' swallowing complaints.