Laryngeal cancer
dmaza@art.blog: Doctor's Message is Still Heard Despite Losing Vocal Cords To Throat Cancer
Laryngeal cancer may also be called cancer of the larynx or laryngeal
carcinoma. Most laryngeal cancers are squamous cell carcinomas, reflecting their
origin from the squamous cells which form the majority of the
laryngeal epithelium.
Cancer can
develop in any part of the larynx, but the cure rate is affected by the location of the
tumour. For the purposes of tumour staging,
the larynx is divided into three anatomical regions: the glottis (true
vocal cords, anterior and posterior commissures); the supraglottis
(epiglottis,
arytenoids
and aryepiglottic folds, and false cords);
and the subglottis.
Most laryngeal cancers originate in the glottis.
Supraglottic cancers are less common, and subglottic tumours are least
frequent.
Laryngeal cancer may spread by direct extension to adjacent structures, by metastasis
to regional cervical lymph nodes, or more distantly, through the blood
stream. Distant metastates to the lung are most common.
Risk
factors
Smoking is the most important risk
factor for laryngeal cancer. Death from laryngeal cancer is 20 times more
likely for heaviest smokers than for nonsmokers.[1]
Heavy chronic consumption of alcohol, particularly alcoholic spirits, is also significant.
When combined, these two factors appear to have a synergistic effect. Some
other quoted risk factors are likely, in part, to be related to prolonged
alcohol and tobacco consumption. These include low socioeconomic status, male
sex, and age greater than 55 years.
People with a history of head and neck cancer are known to be at
higher risk (about 25%) of developing a second cancer of the head, neck, or
lung. This is mainly because in a significant proportion of these patients, the
aerodigestive tract and
lung epithelium
have been exposed chronically to the carcinogenic effects of alcohol and tobacco. In this
situation, a field change effect may
occur, where the epithelial tissues start to become diffusely dysplastic
with a reduced threshold for malignant change. This risk may be reduced by quitting
alcohol and tobacco.
Symptoms
The symptoms of laryngeal cancer
depend on the size and location of the tumor. Symptoms may include the
following:
- Hoarseness or other voice changes
- A lump in the neck
- A sore throat or feeling that something is stuck in the throat
- Persistent cough
- Stridor
- Bad breath
- Earache ("referred")
Incidence
Incidence is five in 100,000 (12,500
new cases per year) in the USA.
The American Cancer Society estimated that 9,510 men and women (7,700 men and
1,810 women) would be diagnosed with and 3,740 men and women would die of
laryngeal cancer in 2006.
Laryngeal cancer is listed as a
"rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH).
This means that laryngeal cancer affects fewer than 200,000 people in the U.S.
Each year, about 2,200 people in the
U.K. are diagnosed with laryngeal cancer.
The disease is also rarely seen in
Canada. The disease affected only 128 individuals in the province of British
Columbia in 2009, the majority being males.
Diagnosis
Diagnosis is made by the doctor on
the basis of a medical history, physical examination, and special
investigations which may include a chest x-ray,
CT or MRI scans, and tissue biopsy. The examination of the larynx
requires some expertise, which may require specialist referral.
The physical
exam includes a systematic examination of the whole patient to assess
general health and to look for signs of associated conditions and metastatic
disease. The neck and supraclavicular fossa are palpated to feel
for cervical adenopathy, other masses, and laryngeal crepitus. The oral cavity
and oropharynx
are examined under direct vision. The larynx may be examined by indirect laryngoscopy using a small angled
mirror with a long handle (akin to a dentist's mirror) and a strong light.
Indirect laryngoscopy can be highly effective, but requires skill and practice
for consistent results. For this reason, many specialist clinics now use
fibre-optic nasal endoscopy where a thin
and flexible endoscope,
inserted through the nostril, is used to clearly visualise the entire pharynx and
larynx. Nasal endoscopy is a quick and easy procedure performed in clinic. Local
anaesthetic spray may be used.
If there is a suspicion of cancer, biopsy is
performed, usually under general anaesthetic. This provides histological
proof of cancer type and grade. If the lesion appears to
be small and well localised, the surgeon may undertake excision biopsy, where
an attempt is made to completely remove the tumour at the time of first biopsy.
In this situation, the pathologist will not only be able to confirm the
diagnosis, but can also comment on the completeness of excision, i.e., whether
the tumour has been completely removed. A full endoscopic examination of the
larynx, trachea, and esophagus is
often performed at the time of biopsy.
For small glottic tumours
further imaging may be unnecessary. In most cases, tumour staging is completed
by scanning the head and neck region to assess the local extent of the tumour
and any pathologically enlarged cervical lymph nodes.
The final management plan will
depend on the site, stage (tumour size, nodal spread, distant metastasis),
and histological type. The overall health and wishes of the patient must also
be taken into account.
Treatment
Specific treatment depends on the
location, type, and stage of the tumour. Treatment may involve surgery, radiotherapy,
or chemotherapy,
alone or in combination. This is a specialised area which requires the
coordinated expertise of ear, nose and throat (ENT) surgeons (otolaryngologists)
and oncologists.
References
1. Ridge JA, Glisson BS, Lango MN, et al. "Head
and Neck Tumors" in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ
(Eds) Cancer
Management: A Multidisciplinary Approach. 11 ed. 2008.
3.
Samuel W. Beenken, MD. "Laryngeal Cancer (Cancer
of the larynx)". Laryngeal Cancer (Cancer of the larynx).
Armenian Health Network, Health.am. Retrieved 2007-03-22.
4. "Annual
Report on the Rare Diseases and Conditions Research". National
Institutes of Health. Retrieved 2007-03-22.
5.
"Causes
of laryngeal cancer". Cancerbackup-cancerbackup.org.uk. Retrieved
2007-03-22.
6. "New
Cancer Diagnoses for 2009". BC Cancer Agency. Retrieved 2012-01-06.
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