Physiological Changes to the Swallowing Mechanism Following (Chemo)radiotherapy for Head and Neck Cancer: A Systematic Review

Abstract

Emerging research suggests that preventative swallowing rehabilitation, undertaken pre-or during (chemo)radiotherapy ([C]RT), can significantly improve early swallowing outcomes for head and neck cancer (HNC) patients. However, these treatment protocols are highly variable. Determining specific physiological swallowing parameters which are most likely to be impacted post-(C)RT would assist in refining clear targets for preventative rehabilitation.Therefore, this systematic review (1) examined the frequency and prevalence of physiological swallowing deficits observed post-(C)RT for HNC, and (2) determined the patterns of prevalence of these key physiological deficits over time post-treatment. Online databases were searched for relevant papers published between January 1998 and March 2013. In total, 153 papers were identified and appraised for methodological quality and suitability based on exclusionary criteria. Ultimately, nineteen publications met the study's inclusion criteria.Collation of reported prevalence of physiological swallowing deficits revealed reduced laryngeal excursion, base of tongue (BOT) dysfunction, reduced pharyngeal contraction and impaired epiglottic movement as most frequently reported. BOT dysfunction and impaired epiglottic movement showed a collective prevalence of over 75% in the majority of patient cohorts, whilst reduced laryngeal elevation and pharyngeal contraction had a prevalence of over 50%. Sub-analysis suggested a trend that the prevalence of key deficits is dynamic although persistent over time. These findings can be used by clinicians to inform preventative intervention, and support the use of specific, evidence-based therapy tasks explicitly selected to target the highly prevalent deficits post-(C)RT for HNC.

Pathophysiology of Radiation-Induced Dysphagia in Head and Neck Cancer

“…Early inflammatory damage to mucosa (i.e., xerostomia, mucositis) and/or radiation dose have been significantly correlated with dysphagia at 6–12 months post-treatment [40], indicative of consequential effects. However, dysphagia can also present years (>2) after treatment with no appreciable early symptoms, which may be due to fibrosis [41,42] and/or atrophy [43,8,41,44–46], and is suggestive of a generic effects [17]. …”

Swallowing interventions for the treatment of dysphagia after head and neck cancer: a systematic review of behavioural strategies used to promote patient adherence to swallowing exercises

“…Dysphagia is a major patient concern after cancer treatment due to the detrimental impact on patients’ quality of life (QOL) [3]. Improvement of swallowing function and earlier restoration of eating and drinking after surgery or chemo-radiation treatments may be achieved with swallowing rehabilitation exercises [4, 5]. Despite this, non-adherence to swallowing exercises in this population is reported to be high [6].…”

Improving swallowing outcomes in patients with head and neck cancer using a theory-based pretreatment swallowing intervention package: protocol for a randomised feasibility study

“…Swallowing difficulties may arise secondary to the presence of tumours in the mouth and throat, 6 from damage or resection of swallowing-related soft tissues and nerves during surgical intervention 7 and from the side effects and long-term tissue damage following chemoradiation. 8 Swallowing interventions that may ameliorate Strengths and limitations of this study ▪ Use of a randomised controlled trial design to minimise bias and differences between groups. ▪ Study design incorporates prior qualitative work to optimise adherence to the intervention.…”