The presence of a tumor in the head and neck region often changes speech and swallowing prior to any treatment. The nature and severity of these changes vary with the tumor site and size. The therapeutic modalities used to treat head and neck cancers also cause alterations in speech and swallowing, which affect the patient's quality of life and ability to function in society.
This paper reviews the literature on speech and swallowing rehabilitation for treated head and neck cancer patients. In addition, new pilot data are presented on the effects of a specific speech-language pathology therapy program on the speech and swallowing abilities of oral and oropharyngeal cancer patients. Future research needs are also discussed.
Impact of Treatment on Speech and Swallowing
Treatment selection is the first line of rehabilitation. Numerous authors have examined the effects of various tumor treatments on speech and swallowing abilities, including the impact of surgical resection and the type of reconstruction, as well as the utilization of radiotherapy for particular tumors.[2-14]
Patients With Oral Cancer
• Surgery—In patients with an oral or oropharyngeal cancer, the extent of resection of the oral tongue and tongue base has been found to be related to swallowing ability; ie, the more extensive the resection, the worse the swallowing function. The reconstruction procedure selected after oral or oropharyngeal cancer resection also plays a major role in the ultimate speech and swallowing abilities of the patient. Although further research is needed, it appears that reconstruction procedures that pull existing oral tissues together (primary closure) result in the best speech and swallowing function, as compared with reconstructive procedures that introduce tissue from other parts of the body, such as the chest wall, arm, and foot. Introduction of tissues from other body parts produces areas of absent sensation, as well as lack of motion.
• Radiotherapy—In contrast to surgical procedures, the application of radiotherapy to the oral cavity leaves tissue and structure intact but introduces other difficulties, particularly with swallowing.[15,16] If the salivary glands are in the radiation field, the resultant xerostomia can make initiation of swallowing difficult. In addition, the fibrosis that can occur as a result of the devascularization of the oral tissues in the radiated field can reduce range of tongue and jaw motion and pharyngeal wall motion, thus affecting both swallowing and speech production.
In general, radiotherapy has a greater effect on swallowing than it does on speech. Since many patients with larger oral and oropharyngeal tumors (T3 and T4) currently receive multimodality treatment (ie, radiotherapy following the surgical procedure), they exhibit the combined effects of both treatment procedures on their speech and swallowing.
• Tumors of the Posterior Oral Cavity—Patients with tumors involving the posterior oral cavity often exhibit disorders in the range of movement of oral and pharyngeal structures. Radiotherapy to the posterior oral cavity and oropharynx also results in changes in structural motion in the pharynx since the pharyngeal constrictors are usually included in the radiation field.[5,6] In addition, surgical treatment of the tongue base and tonsil area usually involves cutting the musculature that attach the tongue base to the pharynx. This pulls the oral tongue posteriorly and ablates sensory receptors critical to triggering the pharyngeal swallow, thus affecting both the oral and pharyngeal stages of swallowing.
Patients With Laryngeal Cancer
Treatment choices for laryngeal cancer range from partial laryngectomy or radiotherapy for small (T1-T2) tumors to total laryngectomy without total glossectomy or radiotherapy and chemotherapy (organ-preserving therapy) for larger (T3-T4) tumors.[2,12,18,19]
• Radiotherapy—Irradiation of the pharynx and larynx generally results in damage to the pharyngeal constrictors, either immediately or later after the completion of therapy. Radiotherapy can result in such significant damage to the pharyngeal constrictors that complete pharyngeal dysfunction during swallowing can result. This is particularly true in patients who receive the combination of high-dose chemotherapy and radiotherapy designed to preserve the structure of the larynx and pharynx.
• Surgery—If a surgical procedure is selected for treatment of laryngeal cancer, small tumors are generally treated with a partial laryngectomy, either a vertical partial laryngectomy (hemilaryngectomy) or a horizontal partial laryngectomy (supraglottic laryngectomy).[2,12,18] Hemilaryngectomy usually involves the removal of one false vocal fold, the ventricle, and the true vocal fold on the same side. Patients with a tumor that requires a hemilaryngectomy exhibit a very brief change in swallowing postoperatively, specifically, reduced laryngeal closure, particularly when swallowing liquids. However, the normal side of the larynx can generally compensate for the damaged side by crossing mid-line and accomplishing closure within a week or two.
In contrast to these short-term swallowing problems, hemilaryngectomy often leaves the patient with a long-term moderate to severe voice impairment, such that loud talking is significantly restricted and the patient's voice is moderately to severely hoarse.
If the tumor is located in the supraglottis, a supraglottic laryngectomy is usually the treatment of choice. This resection involves removal of the epiglottis, a part or all of the hyoid bone, the aryepiglottic folds, the false vocal folds, and the ventricle. The excision cuts right around the arytenoid cartilages, leaving the true vocal folds to protect the airway along with the reconstructed entry to the larynx, comprised of the base of tongue and arytenoid cartilages (Figure 1). Most patients who have undergone a supraglottic laryngectomy are able to speak clearly since the true vocal folds are not affected. However, these patients usually exhibit a prolonged period of swallowing difficulty, which requires swallowing therapy to restore normal deglutition.
Recovery of swallowing function in these patients generally involves retraining the tongue base and arytenoid to contact each other and close the airway entrance, thereby preventing the entry of food or liquid into the airway during swallowing. In general, it takes 4 to 6 weeks for the patient who has undergone a supraglottic laryngectomy to resume safe and efficient oral intake. If the surgical procedure is extended to include a part of the vocal fold(s) or the tongue base, the duration of rehabilitation is significantly prolonged. With a large tongue base resection, the oral contents will dump directly into the airway during swallowing and be aspirated. Thus, if a significant part of the tongue base is removed, the patient may never be able to relearn to swallow, and the procedure may need to be converted to a total laryngectomy.
Total laryngectomy for larger tumors (T3 and T4) results in complete loss of voice, requiring an artificial larynx, esophageal voice, or a surgical pros-thetic voice restoration procedure. Currently, surgical prosthetic voice restoration can be accomplished at the time of the total laryngectomy so that the patient's period of voicelessness is relatively short.
Total laryngectomy also results in changes in swallowing because of the reduction in pharyngeal wall contraction and pharyngo-esophageal pressure in the newly reconstructed pharyngoesophagus. Thus, the oral tongue and tongue base must increase their work to compensate for the lack of pharyngeal driving pressure on the food and to clear the bolus through the pharyngo-esophagus. As a result, after total laryngectomy, many patients complain that they must work harder in order to swallow. Despite this need for greater effort when swallowing, most patients should be able to eat a normal diet within a month after total laryngectomy.
Several anatomic abnormalities that occur after a total laryngectomy can also impair the patient's swallowing ability, including a pseudo-epiglottis (a fold of tissue coming from the pharyngeal wall into the tongue base, which results from the reconstruction). The pseudo-epiglottis forms a side pocket in which food is collected during swallow attempts. Also, a stricture may occur at some point along the reconstructed pharyngo-esophagus, which may block or narrow the food passage.