Cancer of the supraglottis (supraglottic cancer) is almost specifically squamous cell carcinoma (SCC). This article discusses the anatomy of the supraglottis, describes the staging of supraglottic lesions, and offers a summary of treatment options.
Squamous Cell Carcinoma of Epiglottis
History of the Procedure
During the previous 150 years, the treatment of supraglottic tumors has progressed considerably. In 1852, Horace Green reported the first surgical resection of a laryngeal lesion, a polyp in the ventricle, removed under direct vision. By 1859, the first transcervical resection of an epiglottic neoplasm was reported. Chevalier Jackson reinvented supraglottic surgery in 1915, when he used a laryngoscope and a punch biopsy to eliminate an epiglottic growth. Alonso first explained conservation surgery for cancer of the supraglottic larynx in 1947, and, in 1958, Ogura formalized the procedure as the supraglottic laryngectomy. During the 1950s, the surgical microscope and endotracheal anesthesia were offered on this disease. In the 1970s, the carbon dioxide laser began to be used for supraglottic growths.
Problem
SCC of the supraglottis is seen less regularly than cancer of the glottis, and is dealt with in a different way from tumors of the glottis or subglottis. Since of its location, the disease and its treatment can affect the function of the larynx, consisting of speech, swallowing, and breathing.
Public health
Frequency
Laryngeal cancer is the 2nd most typical type of head and neck cancer worldwide. In the United States, approximately 12,500 new cases are identified each year. In 2002, around 160,000 cases of laryngeal cancer and 90,000 deaths were reported worldwide.
Laryngeal cancer is the 11th most common cancer in men around the world but is much less typical in women. Men have been reported to have as much as 30 times the risk that women have for this disease. Older people are also at a greater risk for laryngeal cancer; the highest number of diagnoses is made in patients age 60-74 years.
The portion of laryngeal cancers that originate in the supraglottis varies from country to country. In the United States, for example, roughly 30-40% of laryngeal cancers come from the supraglottis, while a lot of happen in the glottis. In Spain and Finland, however, the supraglottis is the most frequent subsite.
Etiology
Typically, the global occurrence of SCC is proportional to tobacco and alcohol use. In societies where tobacco is chewed rather than smoked, tumor location favors the mouth rather than the larynx.
Various studies have associated smoking of tobacco items with SCC of the larynx. In fact, some studies have show that97% of patients with laryngeal cancer smoked. When compared to men who did not smoke, men who smoked a minimum of 1.5 packs of cigarettes per day for more than 10 years were found to have a 30-fold increased risk of establishing laryngeal cancer.
The risk for supraglottic cancer has actually been discovered to be greater with making use of black (air-cured) tobaccos than with the use of blonde (flue-cured) tobaccos. This distinction is not found with glottic cancers, recommending that the etiology for supraglottic cancers and glottic cancers might differ.
Research studies with controls for age, race, and smoking cigarettes habits also suggest that usage of alcohol increases the risk of laryngeal cancer. Alcohol usage has actually been revealed to have a synergistic result with cigarette smoking; therefore, the risk of developing carcinoma of the throat is increased 100-fold in people who both smoke and drink. This might be partly due to the fact that alcohol acts as a solvent for the carcinogens of tobacco.
In 1946, Slaughter developed the theory of field cancerization in growths of the head and neck. In essence, this theory presumes that the entire mucosa of the aerodigestive tract, when exposed to the very same toxic substances, risks advancement of carcinoma. The vulnerable epithelium goes through progressive modifications that cause malignancy as direct exposure to toxic substances continues. For this reason, multiple areas of precancerous modification can trigger concurrent sores. Supporting this theory is the high rate (4%) of synchronous sores discovered upon workup of patients with sores of the upper aerodigestive tract.
Malnutritions, radiation exposure, human papillomavirus (HPV), and gastroesophageal reflux are other elements related to laryngeal SCC.
Also read: Epiglottis Function in Digestive System
Pathophysiology
The supraglottis is embryologically stemmed from the buccopharyngeal anlage in the area of the 3rd and fourth branchial arches. The glottis and subglottis stem from the tracheobronchial anlage in the region of arches 5 and 6. Hence, the throat essentially consists of 2 hemilarynges, each with different embryonal derivation and largely independent lymphatic flow. Regardless of the theoretical separation of the supraglottis from the rest of the larynx, no anatomical or histological barrier has been identified. Furthermore, supraglottic growths attacking the paraglottic area have access to the glottis by means of the medial surface area of the thyroid cartilage.
Lymphatic vascularity in the supraglottis is much denser than in the glottis and subglottis. This is essential in the development of supraglottic cancer and leads to a substantially greater occurrence of cervical lymph node metastases in tumors of this subsite.
Discussion
Symptoms
Very little changes in the vibration of the singing cord due to tumor development frequently cause dysphonia or hoarseness at an early stage in glottic cancer. Subglottic cancers can cause respiratory tract compromise at an early stage. Supraglottic cancers are less most likely than glottic and subglottic cancers to produce noticeable symptoms such as these early in the disease course and are most likely to provide with the less specific symptoms of persistent dysphagia, odynophagia, or otalgia. Patients with SCC of the supraglottis are not limited to these symptoms, nevertheless, and may likewise provide with hoarseness, hemoptysis, stridor, or chronic cough. Patients with SCC of the supraglottis are most likely to present with a neck mass, partly since patients with supraglottic cancer normally present later than patients with glottic cancer, and partially since of the differences in anatomy and lymphatic drainage,
Assessment
Due to that supraglottic patients with SCC often present with nodal disease, palpation of the neck is important. Health examination might expose laryngeal or cervical findings.
Evaluation with a laryngeal mirror or a flexible nasopharyngoscope helps in visualization of supraglottic lesions.
Relevant Anatomy
The supraglottic larynx is segmented into 4 neighborhoods, as follows: (1) aryepiglottic folds, (2) arytenoids, (3) false cords, and (4) epiglottis. For tumor-staging purposes, the epiglottis is additional partitioned into suprahyoid and infrahyoid areas. These areas of the supraglottis are structured within the structure of the supraglottic larynx, which includes the upper half of the thyroid cartilage, the arytenoid cartilages, and the epiglottis.
Supraglottis subsites
See the list below:
- Suprahyoid epiglottis (lingual and laryngeal surface areas)
- Infrahyoid epiglottis
- False cables
- Arytenoid
- Aryepiglottic folds
Supraglottic squamous cell carcinoma (SCC) follows a predictable pattern of spread. Although tumors might extend inferiorly to include the vocal folds and subglottis, invasion more often occurs in surrounding sites outside the throat such as the base of tongue, vallecula, pyriform sinus, and postcricoid region. As the disease progresses, growths of the supraglottis have the tendency to metastasize to regional lymph nodes.
