After Head and Neck Cancer Treatment
by Jan S. Lewin, PhD
Speech and swallowing dysfunction are frequent after-effects of head and neck cancer and its treatment. More than 75 percent of those treated for cancers of the vocal folds will experience changes in their voice. And at least 50 percent of head and neck cancer survivors have swallowing dysfunction and may not even realize it because of the effect treatment has had on sensory awareness. It is also important to note that, as the intensity of our cancer treatments has increased, the long-term side effects have become more severe. This often results in long-term functional problems, particularly in swallowing, that are difficult to improve and frequently remain irreversible. It is, therefore, important to have a realistic understanding of the long-term functional effects of any head and neck cancer treatment you may be considering because the restoration of communication and your ability to swallow may be critical factors to consider as you make decisions about treatment.
How Speech and Swallowing Work
Speech and swallowing are highly complex processes that depend on precisely coordinated interactions of the structures of the oral cavity (mouth), pharynx (throat), and larynx (voice box). These interactions require extensive neural control, almost like a “functional timeshare” that must ensure respiration, phonation, and swallowing while avoiding adverse events, such as aspiration. Expert evaluation and rehabilitation of speech and swallowing function is critical for head and neck cancer survivors and should begin at the time of cancer diagnosis.
The most common problems experienced by people with head and neck cancer include difficulty with tongue movements (especially those that involve the back of the tongue), problems with the contraction of the muscles of the pharynx, and limited excursion of the larynx that prevents movements that are important for airway protection. All these actions are critical to the ability to speak, eat, and drink by mouth.
At least 50 percent of head and neck cancer survivors have swallowing dysfunction and may not even realize it.
It is important to realize that patients’ reports of speech and swallowing abilities are often unreliable. In other words, perception doesn’t always equal actual ability. After cancer treatment, some people do not report problems swallowing while, in fact, they are silently, without coughing or any other indication, aspirating what they swallow. That is, food is entering the windpipe, placing the individual at risk for pneumonia. Alternatively, people with radiation-induced xerostomia, or dryness of the mouth, frequently report abnormal swallowing when, in fact, their ability to swallow is quite normal.
Tests that Measure Speech and Swallowing Function
Two of the most common tests used to evaluate the ability to swallow safely are the modified barium swallow (MBS) study and the fiberoptic endoscopic evaluation of swallowing (FEES). The MBS, also referred to as a videofluoroscopic examination of swallowing, is a dynamic radiographic assessment, much like a moving X-ray, in which the patient is asked to swallow several different food types while the speech pathologist observes swallowing physiology to determine any abnormalities or problems that will interfere with the ability to eat and drink safely by mouth. Alternatively, FEES is an endoscopic procedure that can easily be performed in the clinic during an office visit. A small tube, or endoscope, is placed into the nose that allows the examiner to observe swallowing while the individual is eating and drinking. Depending on the indications for either swallowing examination, both the MBS study and FEES provide critical information regarding a person’s ability to safely maintain an oral diet.
In addition to the evaluation of swallowing, speech and voice evaluation should include an examination of sound production and observation of vocal fold movement. Videostroboscopy is the best clinical assessment for visualization of the larynx and assessment of true vocal fold vibration. It is not a radiologic procedure. It is performed as an office procedure and provides important information regarding the ability of the larynx to function properly to produce sound.
How Head & Neck Cancer Treatment Affects Speech and Swallowing
After surgery, speech and swallowing are generally most impaired when surgery damages the tongue, specifically the anterior tongue for speech and the tongue base or root of the tongue for swallowing. The degree of impairment often depends on the quality, rather than the extent, of reconstruction. Some people who have undergone total glossectomy, or removal of the entire tongue, swallow better than those who have undergone partial resections that prevent tongue movement. Speech and swallowing therapy is essential for functional recovery.
Research shows that people who adhere to swallowing exercises have the best chance to avoid permanent feeding tubes and continue to eat by mouth.
Effects of radiation therapy can produce both immediate and long-term changes in speech, voice, and swallowing that may increase in severity years after the completion of treatment. Effects vary among individuals, but most people will experience some degree of speech and swallowing impairment. People who cannot swallow adequately before treatment are at higher risk for long-term swallowing disability after treatment and may require a permanent feeding tube. The addition of chemotherapy can make the problems worse because chemotherapy intensifies the effects of the radiation. New regimens of intensity-modulated radiation therapy (IMRT) are used routinely to treat head and neck cancer. Alternatively, the use of intensity-modulated proton beam therapy (IMPT) is another alternative to treat cancer. The goals of both IMRT and IMPT are to cure the disease while protecting tissue and organs that are not involved with disease in order to reduce normal tissue damage, thereby preserving function. Both alternatives continue to be investigated to determine the types of head and neck cancer that will be best managed by either IMRT or IMPT.
Most swallowing problems occur because of the scarring or fibrosis that happens after radiation therapy. As much as possible, you should continue to swallow throughout the course of radiation therapy. Early swallowing recovery from radiation therapy may be misleading because of the delayed fibrosis and nerve damage, or neuropathy, which may occur years after the completion of radiation therapy. These late effects of radiation can result in problems related to chewing, muscle contraction, and airway protection. Even brief periods of not eating by mouth should be avoided, but it is important that the type of foods you eat are ones that you can swallow safely without aspirating. Changes in posture and various types of exercises are often used to strengthen the muscles involved in swallowing. Continuing to eat by mouth and starting swallowing exercises early are felt to provide the best prevention of long-term swallowing problems after radiation therapy. Research shows that people who adhere to swallowing exercises have the best chance to avoid permanent feeding tubes and continue to eat by mouth. New research is investigating whether simply maintaining an oral diet throughout radiation therapy will equally avoid the need for a permanent feeding tube, in select patients. However, at the present time, all patients who are at risk for long-term radiation-associated swallowing problems are encouraged to strictly follow their swallowing exercise regimen. In addition, both research and experience show that delaying the placement of a feeding tube until it is needed may, in fact, help preserve long-term swallowing function.
For some people, particularly those with cancer in the oropharynx and larynx, the use of laser and robotic surgeries are often able to spare the muscles that are critical to speech and swallowing function. However, even when treatment spares organs, preservation of speech and swallowing cannot be ensured. In other words, just because the organ can be saved does not mean it will work. It is important to discuss realistic expectations for functional recovery after organ-sparing procedures with your doctor and your speech pathologist because neither speech nor swallowing may ever fully return to normal, but good functional results are possible.
The focus of speech and swallowing intervention should be early and preventive to maximize restoration following treatment. People who are going to receive treatment for head and neck cancer and are at risk for speech or swallowing problems should see a knowledgeable speech pathologist before treatment begins to start appropriate therapy to prevent long-term speech and swallowing deterioration.
Dr. Jan Lewin is a professor in the Department of Head and Neck Surgery and chief of the Section of Speech Pathology and Audiology at the University of Texas MD Anderson Cancer Center in Houston, TX.
This article was published in Coping® with Cancer magazine, September/October 2018.