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Cancer of the larynx
Cancer of the larynx also may be called laryngeal cancer. Cancercan develop in any part of the larynx. Most laryngeal cancers are squamous cell carcinomas, reflecting their origin from the squamous cellswhich form the majority of the laryngeal epithelium. 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, arytenoidsand aryepiglottic folds, and false cords); the subglottis. Most laryngeal cancers originate in the glottis. Supraglotticcancers are less common, and subglottictumours are least frequent. Laryngeal cancer may spread, either by direct extension to adjacent structures, by metastasisto regional cervical lymph nodesor more distantly, to the lung in particular.
Risk FactorsIn the Western world, smoking is the most important risk factor for laryngeal cancer. 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 previous history of head and neck cancer are known to be at much higher risk (about 25%) of developing a second cancer of the head and neck, or lung cancer (about 10%.)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 to alcohol and tobacco. In this situation, a field change effectmay occur, where the epithelial tissues start to become diffusely dysplasticwith a reduced threshold for malignant change. This risk may be reduced by quitting alcohol and tobacco. SymptomsThe symptoms of cancer of the larynx depend mainly on the size of the tumor and where it is in the larynx. Symptoms may include the following:
Needless to say, these symptoms are not specific for cancer. DiagnosisDiagnosis is made by the doctor on the basis of a careful medical history, physical examination, and special investigations which may include Chest X-Ray, CTor MRIscans, and tissue biopsy. The examination of the throat requires some expertise, which may require specialist referral. The physical examincludes a systematic examination of the whole patient to assess general health, 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 laryngoscopyusing a small angled mirror with a long handle (akin to a dentist's mirror) and a strong light. Indirect laryngoscopycan be highly effective, but requires skill and practice for consistent results. For this reason, many specialist clinics now use fibre-optic Nasal endoscopywhere a thin and flexible endoscope, inserted through the nostril, is used to clearly visualise the entire pharynx and larynx. Nasal endoscopyis a quick and easy procedure, performed in clinic. Local anaesthetic spray may be used. If there is a suspicion of cancer, biopsyis usually performed under general anesthetic. This provides definitive histologicalproof 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. For small glottictumours further imaging may be unnecessary. In most cases, tumour staging is completed by scanning the head and neck region to accurately assess the local extent of the tumour and any pathologically enlarged cervical lymph nodes. The final management plan will depend on the specific 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. TreatmentSpecific 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 dedicated ear nose and throat (ENT) surgeons (otolaryngologists) and oncologists. External links
Categories: Oncology| Types of cancer
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