Risk factors: Studies have found that as many as 90 percent of
people with head
and neck cancers, particularly of the oropharynx,
hypopharynx, and larynx, have a history of smoking cigarettes or chewing tobacco,
and as many as 80 percent have a history of drinking alcohol. Risk increases with
the frequency, duration, and number of “pack-years” of cigarette smoking,
independent of alcohol consumption. (One pack-year is defined as equivalent to
smoking one pack, or twenty cigarettes, per day for one year.) One study indicated
that smoking or chewing tobacco in conjunction with excess drinking of alcohol
increases the risk beyond that for those who use either tobacco or alcohol alone.
In a study among those who never smoked, only those with excessive amounts of
alcohol consumption (three or more drinks per day) were at increased risk of head
and neck cancers.
Other factors vary by tumor site and include Chinese ancestry, consumption of
preserved and salted foods, wood dust exposure, and infection with the
Epstein-Barr
virus for nasopharyngeal cancer; poor oral hygiene, a diet
low in fruits and vegetables, chewing betel quid, and infection with the
human
papillomavirus (HPV) for oropharyngeal cancer; Plummer-Vinson
syndrome, a disorder characterized by severe anemia and trouble swallowing, for
hypopharyngeal cancer; and asbestos exposure for laryngeal cancer.
Individuals of East Asian descent who drink alcohol and possess a genetic mutation
that prevents effective elimination of acetaldehyde, a carcinogen created by
metabolism of alcohol, are at greater risk for oropharyngeal cancer.
Etiology and the disease process: Most throat cancers begin in
squamous cells lining mucosal surfaces in the throat. Squamous cell cancers grow
aggressively. They begin as carcinomas in situ, abnormal cells lining the cells in
the epithelium, before they progress to invasive squamous cell
cancers. Salivary gland tumors can develop in the mucosal
lining of the oropharynx and oral cavity.
What makes squamous cells become cancerous is unknown, but it is believed that tobacco and alcohol use damage the deoxyribonucleic acid (DNA) in the cells of the mouth and throat, causing changes that lead to cancer.
Incidence: According to the National Cancer Institute, in 2014,
there were an estimated 12,630 new cases of laryngeal cancer and 14,410 new cases
of pharyngeal cancer. Furthermore, an estimated 3,610 people will die of laryngeal
cancer and 2,540 will die of pharyngeal cancer. Cancers of the throat occur more
often in men than in women, with men making up approximately 80 percent of those
with hypopharyngeal cancer
and 70 percent of those with nasopharyngeal cancer. The incidence of head and neck
cancers has declined since the 1980s, attributable in part to a drop in the number
of people smoking cigarettes.
Symptoms: Symptoms of throat cancer may be mild or absent but may
include a lump or sore that does not heal or becomes larger, sore throat, trouble
swallowing, and a change in voice such as hoarseness. Patients with cancer of the
oropharynx or hypopharynx may experience ear pain, and those with cancer of the
nasopharynx may have ear pain and difficulty hearing, headaches, and difficulty
breathing or talking. Symptoms of cancer of the larynx may include sore throat,
hoarseness, ear pain, or a lump in the neck.
Screening and diagnosis: There are no routine screening tests for
throat cancer for asymptomatic patients. If throat cancer is suspected, the
physician will take a complete medical history for risk factors and perform a
physical exam. During the physical exam, the physician will palpate for lumps in
the throat to rule out other conditions related to the symptoms, look for signs of
metastasis, and determine the patient’s overall health. Then, the physician will
most likely perform an endoscopy to view areas that are not visible during a
physical exam and to look for lesions. (A laryngoscope examines the larynx; a
nasopharyngoscope examines the nasal cavity and nasopharynx.) During this
procedure, the physician will excise tissue for examination. Depending on the
location of the tumor, the biopsy can be one of three types: an
exfoliative biopsy, incisional biopsy, or fine needle aspiration biopsy (commonly
done to stage oropharyngeal cancer). The physician may recommend a panendoscopy, a
diagnostic procedure done under general anesthesia during surgery to thoroughly
examine the nose, throat, voice box, esophagus, and bronchi to look for areas of
lesions and obtain a biopsy.
If cancer is present, it will be staged, from Stage 0, localized cancer, to
Stage IV, metastasized cancer. Staging depends not only on the pathology results
but on clinical data such as results of the endoscopy, findings on physical
examination, and results of any imaging studies. Imaging studies may include an
X-ray to determine if there is cancer in the lungs; computed tomography (CT) scans
for a cross-sectional picture of the size, location, shape, and position of the
tumor; magnetic resonance imaging (MRI); positron emission tomography (PET) to see
if the cancer has spread to nearby lymph nodes; and a barium swallow, a series of
X-rays to determine if the cancer has spread to the esophagus in the digestive
tract and to see if the cancer affects swallowing.
Treatment and therapy: If cancer is present, the physician will
discuss treatment options, taking into consideration the patient’s overall health,
prognosis, staging, psychosocial supports, treatment side effects, and the impact
of the cancer and treatment on functions such as swallowing, talking, and chewing.
The patient’s medical team may consist of otorhinolaryngologists, oral surgeons,
pathologists, plastic surgeons, prostodontists, and radiation and medical
oncologists. Other allied health professionals such as dieticians, speech
pathologists, physical therapists, and social workers may be involved as
needed.
Surgery and radiation therapies are commonly used for treating throat cancers, particularly when the tumor is small and can be destroyed before spreading to other areas of the body. Radiation therapy may follow surgery if not all the cancer has been removed, or radiation may be used before surgery to preserve the voice. Individuals receiving radiation therapy may experience side effects including nausea, irritation and sores in the mouth, decreased appetite, earaches, and stiffness in the jaw.
If a larger tumor is involved or if the cancer has spread, a combination of
radiation and chemotherapy is often successful and can preserve the voice box.
Rarely will a partial laryngectomy be recommended and only in
cases in which the larynx and primary tumor must be removed. Palliative
care is needed for individuals whose primary throat cancer
has spread to other organs or distant parts of the body and cannot be treated.
Prognosis, prevention, and outcomes: The five-year survival rates
for throat cancers vary based on the location and the stage of the cancer at the
time it was found. The five-year survival rates for stage I laryngeal cancer is 59
percent for cancer of the supraglottis, 90 percent for cancer of the glottis, and
65 percent for cancer of the subglottis. The five-year survival rate is 53 percent
for stage I hypopharyngeal cancer and 72 percent for stage I nasopharyngeal
cancer. However, these rates drop when these cancers are detected after
metastasis: the five-year survival rate for stage IV cancers is 34 percent for
cancer of the supraglottis, 44 percent for cancer of the glottis, 32 percent for
cancer of the subglottis, 24 percent for hypopharyngeal cancer, and 38 percent for
nasopharyngeal cancer. According to the American Cancer Society, the relative
five-year survival rate is 66 percent for cancers of the oropharynx and tonsils,
although survival rates by stage are not available.
Rehabilitation is often a critical component in caring for patients treated for throat cancers. Many patients need therapy for assistance in speaking and swallowing following treatment. Patients may need dietary counseling as well. Those who receive a laryngectomy will have a stoma, a surgical opening in the throat, and will need to learn how to care for it and how to speak again if the stoma is permanent.
Follow-up care for those treated for throat cancer is essential to ensure that
the cancer does not recur. Individuals with a prior diagnosis of throat cancer are
at the highest risk of recurrence of the cancer within two to three years of
initial diagnosis. During follow-up visits, the physician will perform a physical
exam and sometimes order X-rays, blood tests, and imaging studies. Regular dental
exams may be necessary as well. If patients received radiation therapy, the
physician may monitor functioning of the thyroid and pituitary glands. The
treating physician will also urge patients to stop drinking alcohol and to pursue
smoking
cessation, as alcohol and tobacco have been shown to
compromise treatment and increase the risk that a second cancer will develop.
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