General
This review covered two research questions: (1) what are the negative side effects of concomitant CRT on swallowing, mouth opening, pain and quality of life before and after treatment in head and neck cancer patients and (2) what are the rehabilitation options to ameliorate these side effects? Fifteen papers were identified that could be assessed according to a predefined set of ‘quality’ criteria. The majority of these articles focussed on the outcomes swallowing, quality of life and nutrition, but also on trismus and pain.
In most papers, swallowing was assessed by means of videofluoroscopy modified barium examination (VBMS). The most common abnormalities at baseline included reduced posterior motion of the base of tongue, delay in the swallow reflex, decreased epiglottic movement, decreased laryngeal elevation, and bolus residue in the vallecula or posterior pharyngeal wall after the completion of the swallow. The same swallowing abnormalities occurred after CRT, but in higher frequencies and in greater severity. Even 1-year posttreatment, swallowing abnormalities still existed. Tumors in the nasopharynx were associated with trismus and reduced oral tongue control. Oropharynx tumors exhibited a high frequency of reduced tongue base retraction and reduced tongue strength and patients with lesions in the larynx most frequently exhibit reduced tongue base retraction, reduced anterior posterior tongue movement, delayed pharyngeal swallow, reduced laryngeal elevation, and reduced cricopharyngeal opening. In addition, CRT seems to increase the aspiration rate, and neck dissections seem to worsen laryngeal elevation.
Most of the reviewed studies were not designed to examine the effects of swallowing therapy, and therefore did not focus on rehabilitation options. Many tongue and swallowing exercises, such as tongue function therapy and swallowing maneuvres, are described in the literature [
17,
21,
48,
97‐
102]. Furthermore, the effectiveness of these swallowing exercises has not yet been assessed systematically in the CRT patient population.
After the designated period of this systematic search had ended, several additional papers were published, three of which (Carroll et al. [
97], Logemann et al. [
103] and Langerman et al. [
104]) warrant a brief review. Carroll et al. and Logemann et al. suggested that (early) rehabilitation might be beneficial. Unfortunately, only limited numbers of patients were involved and neither of these two studies was a randomized clinical trail. Langerman et al. [
104] retrospectively reviewed the incidences of aspiration after CRT in 130 patients, and concluded that aspiration rate increases over time. They also found that the patients with cancer of the larynx and hypopharynx were more likely to be frank aspirators (more than 5% of the swallowed bolus was aspirated).
Quality of life research in the 15 assessed papers was generally well conducted, which is not surprising in view of the many well-designed and validated questionnaires presently available. In general, all papers reported that the overall quality of life scores improved over time and returned to baseline 1 year postCRT.
To evaluate nutritional support, all the reviewed papers used questionnaires or a 4-point-scale. Some studies reported a gradual improvement of oral intake over time and the majority of patients had returned to baseline levels by 12 months. One study reported what might be a good predictor; if the swallow is normal at 6 months posttreatment, it will also be normal at 12 and 18 months [
59]. The data also suggest that the act of eating and swallowing itself may ‘rehabilitate’ the oropharyngeal musculature necessary for swallowing. In other words, keeping the muscles active will keep the muscles useful.
We conclude that this systematic search of the literature provides an answer to the first research question, but that the second question remains unanswered.
Limitations of current studies
Missing information, e.g. about gender, site of lesion, and assessment methods precludes replication in two-thirds of the studies. There was also little uniformity in follow-up times and evaluation tools. Because missing data (drop-outs) could have biased the results, lack of this information is considered a limitation. In addition, only three of the five relevant papers reported intra- or interobserver reliability checks of VMBS.
Data on the effects on mouth opening after CRT is lacking, and in view of the more pronounced side effects of CRT in comparison to RT alone, more reports were expected.
Finally, papers on rehabilitation options and their effects are very sparse. Most studies focussed on the functional outcomes after CRT, but not on possible rehabilitation options. The tradition of evidence-based rehabilitation after organ sacrificing therapies, such as total laryngectomy, has been well-established and the time has now come to invest in evidence-based rehabilitation after CRT [
105].
Future directions
It is clear from the present systematic review that head and neck cancer patients suffer from substantial function losses after CRT. This implies that not only the various functions at stake pre and posttreatment should be measured multidimensionally but also that centers should strive at performing these measures with the same standardized, validated instruments. In addition, prevention and rehabilitation of loss of function should be investigated on a much wider scale. The guidelines of the Dutch Cooperative Group on Head and Neck Cancer already recommended preventative management of trismus and dysphagia [
3]. Other authors also emphasize the importance of rehabilitation [
5,
13,
15,
40].
Besides the swallowing intervention, rehabilitation of trismus should be given attention. Dijkstra et al. [
18] documented that, the effects of therapeutic interventions of trismus are hardly investigated and evidence supporting prevention and treatment programs is generally not provided. Nevertheless, one randomised trial in patients who had undergone radiotherapy for cancer of the head and neck showed that standard stretching exercises with or without the use of tongue depressors, and exercises with the passive jaw moving device TheraBite, did increase mouth opening significantly [
106]. As far as we know, it has not been established if either standard stretching exercises or passive movement using the TheraBite can prevent trismus. Burkhead developed an exercise regimen incorporating the TheraBite device, and found an increased neuromuscular activation of the swallowing muscles (Effect of tongue and jaw position on suprahyoids during swallowing. Paper presented at the ASHA Convention, session 1377, November 2004).
It is, however, uncertain at present which rehabilitation procedures have the best preventative and long-term effect in decreasing functional problems such as swallowing, mouth opening, pain and quality of life in patients with head and neck cancer receiving CRT. The Netherlands Cancer Institute started a Randomised Clinical Trail (prevention of trismus, swallowing and speech problems in patients treated with chemoradiotherapy for advanced head and neck cancer in September 2006). This study compares exercising with or without a device, and investigates if either approach has a preventative or and long-term effect (1-year postCRT) on jaw motion and swallowing function.