Laryngeal cancer overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Faizan Sheraz, M.D. [2]
Overview
Laryngeal cancers arise from squamous cell epithelium of the larynx. 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 tumor. For the purposes of tumor 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); the subglottis. Most laryngeal cancers originate in the glottis. Supraglottic cancers are less common, and subglottic tumors are least frequent. Laryngeal cancer may spread, either 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. Laryngeal carcinoma may be classified into more than 14 subtypes based on anatomical and histological characteristics of the tumor. Laryngeal cancer arises from squamous cells, which are cells that are normally involved in protection of upper respiratory airways. Genes involved in the pathogenesis of laryngeal cancer include p16, NOTCH1, cyclin D1, and TP53. On gross pathology, flattened plaques, mucosal ulceration, and raised margins of the lesion are characteristic findings of laryngeal cancer. On microscopic histopathological analysis, spindle cells, basaloid cells, and nuclear atypia are characteristic findings of laryngeal cancer. Laryngeal carcinoma must be differentiated from laryngeal syphilis, lymphoma, and chronic laryngitis. The prevalence and incidence of laryngeal cancer is approximately 19.5 and 3.3 per 100,000 individuals in the United States, respectively. The estimated number of new cases in the United States in 2014 is 12,630 which corresponds to 0.8% of all new cancer cases. Laryngeal cancer is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH), which means that laryngeal cancer affects less than 200,000 individuals in the US population. In the United Kingdom, 2,369 individuals were diagnosed with laryngeal cancer in 2011. Common risk factors in the development of laryngeal cancer are smoking tobacco, chewing tobacco, and heavy alcohol consumption. According to the American Cancer Society, screening for laryngeal cancer is not recommended. The optimal therapy for laryngeal cancer depends on the stage at the time of diagnosis. The feasibility of surgery depends on the stage of laryngeal cancer at the time of diagnosis.
Historical Perspective
Laryngeal carcinoma was first discovered by Dr. Morgagni, a Byzantine physician. Theodore Bilroth reported a century ago, the first few examples of primary malignant tumors. The surgery for laryngeal cancer started in the 19th century and kept advancing through the 20th century.
Classification
Laryngeal carcinoma may be classified into more than 14 subtypes based on the anatomical and histological characteristics of the tumor. Anatomical classification includes supraglottic, glottic and subglottic laryngeal cancer. Based on histology, laryngeal carcinoma may be classified into acantholytic squamous cell carcinoma, adenosquamous carcinoma, basaloid squamous cell carcinoma, papillary squamous cell carcinoma, spindle cell squamous cell carcinoma, verrucous carcinoma, giant cell carcinoma, lymphoepithelial carcinoma (non-nasopharyngeal), neuroendocrine carcinoma, typical carcinoid tumor (well differentiated neuroendocrine carcinoma) and atypical carcinoid tumor (moderately differentiated neuroendocrine carcinoma)
Pathophysiology
Laryngeal cancer arises from squamous cells, which are cells that are normally involved in protection of upper respiratory airways. Genes involved in the pathogenesis of laryngeal cancer include p16, NOTCH1, cyclin D1, and TP53. On gross pathology, flattened plaques, mucosal ulceration, and raised margins of the lesion are characteristic findings of laryngeal cancer. On microscopic histopathological analysis, spindle cells, basaloid cells, and nuclear atypia are characteristic findings of laryngeal cancer.
Causes
There are no established causes for laryngeal cancer. However, chromium or nickel, asbestos, alcohol and smoking have been associated with laryngeal cancer
Differentiating Laryngeal cancer from other Diseases
Laryngeal carcinoma must be differentiated from laryngeal syphilis, lymphoma, and chronic laryngitis
Epidemiology and Demographics
The prevalence of laryngeal cancer is approximately 19.5 per 100,000 individuals in the United States. The incidence of laryngeal cancer is approximately 3.3 per 100,000 individuals in the United States.The estimated number of new cases in the United States in 2014 is 12,630 which corresponds to 0.8% of all new cancer cases. Laryngeal cancer is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH), which means that laryngeal cancer affects less than 200,000 people in the US population. In the United Kingdom, 2,369 people were diagnosed with laryngeal cancer in 2011.
Risk Factors
Common risk factors in the development of laryngeal cancer are smoking tobacco, chewing tobacco, and heavy alcohol consumption
Screening
According to the American Cancer Society, screening for laryngeal cancer is not recommended
Natural History, Complications and Prognosis
If left untreated, laryngeal cancer produces few symptoms early in the course. Once the tumor has expanded from its site of origin, it may obstruct the airway. Common complications of laryngeal cancer include airway obstruction, neck disfigurement, and voice abnormalities. The prognosis varies with the type and stage of laryngeal cancer. Stage 4 squamous cell carcinoma of larynx has the most unfavorable prognosis. The 3-year survival rate for supraglottic laryngeal cancer and T3 transglottic carcinoma were 91.7% and 73.2%, respectively
Staging
According to the TNM staging system, the stages of laryngeal cancer are based on the tumor size, lymph node involvement, and distant metastasis
History and Symptoms
The hallmark of laryngeal cancer is hoarseness. A positive history of neck lump and hoarseness is suggestive of laryngeal cancer. Based on the location of the tumor, symptoms may differ but commonly includes hoarseness or other voice changes, lump in the neck, sore throat, and persistent cough
Physical Examination
Patients with laryngeal carcinoma are usually well appearing. Physical examination of patients with laryngeal carcinoma is usually remarkable neck swelling, hearing loss, and stridor.
CT
Head and neck CT scan may be helpful in the diagnosis of laryngeal cancer. Findings on CT scan suggestive of laryngeal cancer include solid soft tissue nodule, region of superficial thickening with increased enhancement, and obliteration of fat planes.
MRI
MRI may be helpful in the diagnosis of laryngeal cancer. Findings on MRI suggestive of laryngeal cancer include intermediate to low signal mass and soft tissue enhancement. MRI is better than CT for evaluation of neural metastasis, skull invasion, and intracranial invasion of head and neck cancer
Other Imaging Findings
Other imaging findings for laryngeal cancer inlcude Fluoro-D-glucose positron emission tomography PET which is taken up more by actively metabolic cells. In case of small glottic tumors further imagingmay be unnecessary. Laryngoscopy can be helpful to visualize the tumor.
Other Diagnostic Studies
Fine needle aspiration biopsy has high sensitivity and specificity for laryngeal cancer
Medical Therapy
The optimal therapy for laryngeal cancer depends on the stage at the time of diagnosis.
Surgery
The feasibility of surgery depends on the stage of laryngeal cancer at the time of diagnosis.
Primary Prevention
Effective measures for the primary prevention of laryngeal cancer include smoking cessation and limiting or avoiding alcohol consumption
Secondary Prevention
Secondary prevention measures of laryngeal cancer include routine physical examination and imaging at scheduled intervals after treatment. Dental screening and screening for thyroid cancers are recommended among patients who had received radiation therapy to the oral cavity and cervical region, respectively