Head and neck cancers (HNC) begin in the squamous cells that line the moist, mucosal surfaces inside the head and neck such as the mouth, the nose, and the throat. It is typically categorized by the area in which the malignancies originate. These affected regions can be in the oral cavity, pharynx, larynx, paranasal sinuses and nasal cavity, and salivary glands (National Cancer Institute, 2017). According to ASHA, HNC accounts for approximately 550,000 cases annually with higher incidence seen in men compared to women.
Treatment for this type of cancer can include surgery, radiation, chemotherapy, targeted therapy or a combination of treatments. Organ preservation protocols, such as chemoradiation therapy (CRT), aim to cure the disease as well as maintain respiration, deglutition, speech, and cosmetics (Rinkel et al., 2015). However, most studies reveal that side effects from these organ preservation protocols result in tissue damage of the affected area that causes swallowing dysfunction. According to Kumar et al. (2015), high radiation may lead to swallowing muscle dysfunction and fibrosis, which appears to be the primary reason for swallowing dysfunction after radiotherapy. Radiation may affect anatomical structures necessary for a safe and efficient swallow. When these structures are affected, it may result in the following impairments: weakness of the base of the tongue, prolonged pharyngeal transit time, lack of coordination between swallowing phases, reduced laryngeal closure and epiglottic inversion (Messing et al., 2017). Swallowing intervention targets jaw mobility, range of motion exercises of the tongue, lips or neck, and pharyngeal strengthening (Messing et al., 2017). Swallowing exercises may maintain the function of the oropharyngeal musculature. In addition, swallowing exercises may facilitate better recovery of function and possibly prevent the development of fibrotic changes in the muscles (Govender et al., 2015).
There have been studies that investigated the effects of swallowing treatment for the improvement of swallowing. Kumar et al. (2015) investigated the effects of dysphagia prevention exercises that were done from the day of the onset of radiation therapy and continued until six months post treatment. Mortensen et al. (2015) studied the effects of swallowing exercises that began seven days prior to the start of cancer treatment with an individualized dietary plan for each participant. This paper aims to explore the effectiveness of swallowing exercises to prevent dysphagia during and after CRT of individuals with HNC.
The patients in the studies reviewed had been diagnosed with HNC and underwent treatment via one of the main modalities of surgery, radiotherapy, CRT or a combination of treatments. The majority of the patients were in stage III and IV of their disease. The inclusion criteria included a minimum age requirement of 18 years old (Govender et al. 2017; Mortensen et al. 2015) or 21 years old (Messing et al. 2017). In addition, one study was comprised of participants who had a PEG tube placed one week prior to treatment but were still encouraged to continue to eat and drink as tolerated during CRT (Messing et al. 2017).
The studies used a randomized controlled trial to minimize biases and differences between groups. In addition, studies compared the contrast between providing swallowing exercises versus usual care or no intervention, and how this affected the patients’ swallowing function and their quality of life. Computer-generated services were used to randomize the allocation of participants in groups. In one study, patients and staff members were not blinded during the allocation of groups as they were aware of the intervention provided (Govender et al., 2017). Two of the studies implemented an adherence to treatment journal which was completed daily and up to three months post-CRT (Messing et al. 2017; Mortensen et al. 2015).
Kumar et al. (2015) studied the impacts of early dysphagia intervention on patients with HNC who received intensity-modulated therapy or image guided radiation therapy. There were 50 participants with 25 patients in the control group and 25 patients in the exercise group. The control group did not receive any form of intervention while the exercise group received a variety of strengthening and/or range of motion exercises. For all groups, dysphagia assessments as well as outcome measures were performed prior to receiving any swallowing exercises and after the treatment for a 3rd and 6th month follow-up. The following measures were used to assess overall quality of swallowing: M.D. Anderson Dysphagia Inventory (MDADI), American Speech-Language Hearing Association (ASHA) scale, and Penetration Aspiration Scale (PAS). The MDADI was specifically designed for evaluating the impact of dysphagia on quality of life. The ASHA scale was used for assessing swallowing function. PAS, an 8-point rating scale, was used to assess aspiration using a fiberoptic endoscopic evaluation of swallowing (FEES) that was performed by the ENT.
Messing et al. (2017) studied the effects of prophylactic swallow therapy for patients with HNC undergoing chemotherapy. This study included 60 patients who were randomly assigned to a control group (N=30) or an exercise group (N=30). The control group did not receive any swallowing services but only TheraBite prophylactic exercises in a self-regulated practice. The exercise group received prophylactic swallowing exercises as well as the TheraBite protocol, with a clinician overseeing the exercises. Battery measures were assessed at baseline and at 3, 6, 12 and 24 months. The assessments used were Functional Oral Intake Scale (FOIS), Oromotor Assessment, Oral Cavity Assessment, Common Terminology Criteria for Adverse Events (CTCAE), QLQ-C30, European Organization for Research and Treatment of Cancer (EORTC), and the Head and Neck Quality of Life module. FOIS ratings were measured at all points in the study for patients who were completely dependent on a PEG tube for feedings. The Modified Barium Swallow (MBS) was only administered during the three-month time period due to radiation exposure and cost. It was also identified as the primary time point of interest. Furthermore, the Dysphagia Outcomes Severity Scale (DOSS), Oral Pharyngeal Swallow Efficiency (OPSE) and PAS were also administered to measure dysphagia severity.
Mortensen et al. (2015) also evaluated the impact of prophylactic swallowing exercises of 44 patients diagnosed with head and neck cancer. The exercise group (N=22) was given standard individualized dietary advice by a dietician, were provided with verbal and written instructions, and were encouraged to continue oral food intake if it is safe. They were also instructed to perform exercises for ten repetitions, three times a day for seven days a week prior to starting radiotherapy. Adherence to instruction was documented in an exercise diary that included the number of training sessions performed per day as well as any pain related to the exercises. The control group (N=22) was also given an individualized dietary advice and was encouraged to continue oral food intake. Quality of Life Questionnaire (QLQ), EORTC Head and Neck Submodule, DAHANCA Dysphagia score and objective score (weight, mouth opening, and tube) measures were administered. In addition, an analytical measure (i.e. MBS) was performed for all the participants prior to treatment and at the 2, 5, and 11-month period after completion of radiation therapy.
The types of dysphagia prevention exercises varied from study to study. Kumar et al. (2015) included jaw exercises, tongue exercises, pharyngeal and laryngeal exercises, supraglottic exercises, tongue hold, mouth opening exercises, and range of motion (ROM) exercises. The tongue exercises included movement of tongue in all possible directions (e.g. lateralization, extension, elevation, and/or cupping). The pharyngeal and laryngeal exercises included the Mendelsohn maneuver and Shaker exercise. The Mendelsohn maneuver is a laryngeal exercise where the patient holds a swallow, which helps increase the duration of laryngeal elevation and cricopharyngeal opening. The Shaker exercise is an indirect treatment where patients are asked to lay down and are instructed to raise their head and hold this position. This exercise strengthens suprahyoid musculature including the hyoid bone and larynx.
Messing et al. (2017) used prophylactic exercises that included a set of active exercises, completed twice daily, 7 times per week and up to 3 months post-CRT. The set of exercises includes oromotor strength/stretch exercises and swallowing maneuvers. Oromotor strength/stretch exercises involve mandibular and neck range of motion, labial range of motion exercises, lingual range of motion and strengthening exercises, and pharyngeal strength exercises. Participants also complete the TheraBite exercises adhering to the 7-7-7 protocol which is 7 passive range of motion stretches, performed 7 times, repeated 7 times each day.
In the Mortensen et al. (2015) study, the swallowing exercises included range of motion drills and resistance exercises. Range of motion drills maintained and improved the range of motion of relevant structures and muscle groups. Resistance exercises strengthen the muscles to overcome increased resistance in the tissue. Specific exercises were not explicitly defined.
The results show that patients who received swallowing exercises had better quality of life in terms of social eating (Kumar et al. 2015). The MDADI showed significant improvement from baseline to six months for the exercises group compared to the control group (i.e. a score of 14 vs. 7). ASHA scales showed statistical significance in favor of the group that received swallowing exercises, who were able to swallow almost normally by the end of six months. Patients who did not receive swallowing exercises met their nutritional needs but required modifications in their diet. By the end of six months, among the patients who received swallowing exercises, only 20% (4 out of 25 participants) were at risk from penetration and aspiration. This was a big improvement from the 3-month mark where 32% of the same group were scored low in the PAS. A lower incidence for aspiration for the exercise group was recorded as well, but the results were not statistically significant. However, patients in this group were able to swallow more types of food items and had better cough reflexes.
Messing et al. (2017) found that there was a 10% difference between the exercise group versus the control group on the FOIS, but this number was not considered statistically significant. However, in the exercise group, they found that there was improvement in the oromotor function at six months with greater incisal opening at 24 months. Results from the OPSE battery showed that overall swallow efficiency was found to be statistically significantly better in the exercise group with a higher incidence of a normal swallow compared to the control group. The results indicated that 66% (N=9) of the exercise group adhered to completing the study journal. The remaining participants completed the journal sporadically.
Mortensen et al. (2015) explored the results of swallowing treatments in a total of 21 patients that completed the study. 13 patients withdrew from the study and five patients had a recurrence of cancer and died. These dropouts may have affected the results of the study. The findings show no significant difference between the groups regarding treatment characteristics. Adherence to the exercise started good. By the 5th week, 53% of the participants in the exercise group were exercising at least once a day. By the end on the first year, adherence to the exercise dropped to 33%. Results show no statistical difference in the quality of life between groups.
Although it is widely recognized that undergoing any sort of radiation treatment can negatively impact the anatomy and physiology of structures, participants in the studies received encouraging results from the different protocols provided. Kumar et al. (2015) found that participants who performed swallowing exercises were at lesser risk for aspiration compared to participants who did not. However, it should be noted that 36% of the participants from both the control and exercise group presented silent aspiration at the third month. Silent aspiration was still observed by the six-month time period but decreased to 24% of participants. Therefore, the authors advised to put an NG tube or PEG tube placement upfront to eliminate any silent aspirations that may occur.
The results from the study of Messing et al. (2017) suggested that oromotor function was statistically significantly better for the exercise group at the six-month mark. A study by Carnaby-Mann et al. (2012) showed that the muscle size and composition of the genioglossus, hyoglossus, and mylohyoid, were preserved with similar oral exercises presented (as cited in Messing et al., 2017). However, the results also showed that there was no difference with the FIOS scores between groups. This meant that both groups did not show any difference in the levels of functional oral intake. Both groups presented well-preserved incisal opening with the exercise group showing greater improvements. This may be due to the TheraBite that were provided for both groups of participants. Overall, results suggest that there was significantly less pharyngeal phase impairments and better swallow efficiency in the exercise group.
The only study found that was not statistically significant was by Mortensen et al. (2015). The study showed no statistical benefit of the intervention in patients with dysphagia. However, it should be noted that there was a high number of dropouts throughout the study. 49% of the patients did not complete the study to the 11th month. Consequently, with the small number of participants, the results may not generalize to a larger population.
There were several limitations observed in the studies reviewed. First, patients’ competencies in the swallowing exercises were not completely defined. Therefore, it was unclear whether a specific exercise was not effective due to the nature of the activity or due to the lack of mastery of the specific exercise. Second, most of the studies required the patients to adhere to swallowing exercises but did not explicitly describe on how these exercises were taught to the patients. One of the most common reasons on why patients do not adhere to the protocol is the lack of understanding about the importance of these exercises. Finally, the lack of information in the specificity of exercises makes it difficult to replicate the studies as well as direct future studies in the effects of swallowing exercises.
Overall, swallowing treatment before and after chemotherapy/radiation therapy appears to have a positive effect in the prevention of dysphagia. However, more studies should still be implemented as there are only a very limited number of studies that support this treatment. In conclusion, studies show that significant swallowing function and improved quality of life can be achieved if swallowing exercises are initiated prior to the start of cancer treatment up until three or six months post-CRT. Adherence to the exercise protocol is a primary factor that influences the impact of this treatment in improving swallowing function