Head and neck cancer
Head and neck cancer is a general term encompassing multiple cancers that can develop in the head and neck region. These include cancers of the mouth, tongue, gums and lips, voice box, throat, salivary glands, nose and sinuses.
Head and neck cancer can present a wide range of symptoms depending on where the cancer developed. These can include an ulcer in the mouth that does not heal, changes in the voice, difficulty swallowing, red or white patches in the mouth, and a neck lump.
The majority of head and neck cancer is caused by the use of alcohol or tobacco. An increasing number of cases are caused by the human papillomavirus. Other risk factors include the Epstein–Barr virus, chewing betel quid, radiation exposure, poor nutrition and workplace exposure to certain toxic substances. About 90% are pathologically classified as squamous cell cancers. The diagnosis is confirmed by a tissue biopsy. The degree of surrounding tissue invasion and distant spread may be determined by medical imaging and blood tests.
Not using tobacco or alcohol can reduce the risk of head and neck cancer. Regular dental examinations may help to identify signs before the cancer develops. The HPV vaccine helps to prevent HPV-related oropharyngeal cancer. Treatment may include a combination of surgery, radiation therapy, chemotherapy, and targeted therapy. In the early stage head and neck cancers are often curable but 50% of people see their doctor when they already have an advanced disease.
Globally, head and neck cancer accounts for 650,000 new cases of cancer and 330,000 deaths annually on average. In 2018, it was the seventh most common cancer worldwide, with 890,000 new cases documented and 450,000 people dying from the disease. The usual age at diagnosis is between 55 and 65 years old. The average 5-year survival following diagnosis in the developed world is 42–64%.
Signs and symptoms
Head and neck cancers can cause a broad range of symptoms, many of which occur together. These can be categorised local, general and gastrointestinal symptoms. Local symptoms include changes in taste and voice, inflammation of the mouth or throat, dry mouth, and difficulty swallowing. General symptoms include difficulty sleeping, tiredness, depression, nerve damage. Gastrointestinal symptoms are typically nausea and vomiting.Symptoms predominantly include a sore on the face or oral cavity that does not heal, trouble swallowing, or a change in voice. In those with advanced disease, there may be unusual bleeding, facial pain, numbness or swelling, and visible lumps on the outside of the neck or oral cavity. Head and neck cancer often begins with benign signs and symptoms of the disease, like an enlarged lymph node on the outside of the neck, a hoarse-sounding voice, or a progressive worsening cough or sore throat. In the case of head and neck cancer, these symptoms will be notably persistent and become chronic. There may be a lump or a sore in the throat or neck that does not heal or go away. There may be difficulty or pain in swallowing. Speaking may become difficult. There may also be a persistent earache.
Other symptoms can include: a lump in the lip, mouth, or gums; ulcers or mouth sores that do not heal; bleeding from the mouth or numbness; bad breath; discolored patches that persist in the mouth; a sore tongue; and slurring of speech if the cancer is affecting the tongue. There may also be congested sinuses, weight loss, and some numbness or paralysis of facial muscles.
Mouth
Oral cancer affects the areas of the mouth, including the inner lip, tongue, floor of the mouth, gums, and hard palate. Cancers of the mouth are strongly associated with tobacco use, especially the use of chewing tobacco or dipping tobacco, as well as heavy alcohol use. Cancers of this region, particularly the tongue, are more frequently treated with surgery than other head and neck cancers. Lip and oral cavity cancers are the most commonly encountered types of head and neck cancer.Surgeries for oral cancers include:
- Maxillectomy
- Mandibulectomy
- Glossectomy
- Radical neck dissection
- Combinational.
Nose
affects the nasal cavity and the paranasal sinuses. Most of these cancers are squamous cell carcinomas.Nasopharynx
Nasopharyngeal cancer arises in the nasopharynx, the region in which the nasal cavities and the Eustachian tubes connect with the upper part of the throat. While some nasopharyngeal cancers are biologically similar to the common head and neck cancers, "poorly differentiated" nasopharyngeal carcinoma is lymphoepithelioma, which is distinct in its epidemiology, biology, clinical behavior, and treatment and is treated as a separate disease by many experts.Throat
Most oropharyngeal cancers begin in the oropharynx, the middle part of the throat that includes the soft palate, the base of the tongue, and the tonsils. Cancers of the tonsils are more strongly associated with human papillomavirus infection than are cancers of other regions of the head and neck. HPV-positive oropharyngeal cancer generally has a better outcome than HPV-negative disease, with a 54% better survival rate, but this advantage for HPV-associated cancer applies only to oropharyngeal cancers.People with oropharyngeal carcinomas are at high risk of developing a second primary head and neck cancer.
Hypopharynx
The hypopharynx includes the pyriform sinuses, the posterior pharyngeal wall, and the postcricoid area. Tumors of the hypopharynx frequently have an advanced stage at diagnosis and have the most adverse prognoses of pharyngeal tumors. They tend to metastasize early due to the extensive lymphatic network around the larynx.Larynx
Laryngeal cancer begins in the larynx, or "voice box", and is the second most common type of head and neck cancer encountered. Cancer may occur on the vocal folds themselves or on tissues above and below the true cords. Laryngeal cancer is strongly associated with tobacco smoking.Surgery can include laser excision of small vocal cord lesions, partial laryngectomy, or total laryngectomy. If the whole larynx has been removed, the person is left with a permanent tracheostomy. Voice rehabilitation in such patients can be achieved in three important ways: esophageal speech, tracheoesophageal puncture, or electrolarynx. One would likely require intensive teaching, speech therapy, and/or an electronic device.
Trachea and salivary glands
is a rare cancer usually classified as a lung cancer.Most tumors of the salivary glands differ from the common head and neck cancers in cause, histopathology, clinical presentation, and therapy. Other uncommon tumors arising in the head and neck include teratomas, adenocarcinomas, adenoid cystic carcinomas, and mucoepidermoid carcinomas. Rarer still are melanomas and lymphomas of the upper aerodigestive tract.
Causes
Alcohol and tobacco
and tobacco use are major risk factors for head and neck cancer. 72% of head and neck cancer cases are caused by using both alcohol and tobacco. This rises to 89% when looking specifically at laryngeal cancer.There is thought to be a dose-dependent relationship between alcohol use and development of head and neck cancer where higher rates of alcohol consumption contribute to an increased risk of developing head and neck cancer. Alcohol use following a diagnosis of head and neck cancer also contributes to other negative outcomes. These include physical effects such as an increased risk of developing a second primary cancer or other malignancies, cancer recurrence, and worse prognosis in addition to an increased chance of having a future feeding tube placed and osteoradionecrosis of the jaw. Negative social factors are also increased with sustained alcohol use after diagnosis including unemployment and work disability.
The way in which alcohol contributes to cancer development is not fully understood. It is thought to be related to permanent damage of DNA strands by a metabolite of alcohol called acetaldehyde. Other suggested mechanisms include nutritional deficiencies and genetic variations.
Tobacco smoking is one of the main risk factors for head and neck cancer. Cigarette smokers have a lifetime increased risk for head and neck cancer that is 5 to 25 times higher than the general population. The ex-smoker's risk of developing head and neck cancer begins to approach the risk in the general population 15 years after smoking cessation. In addition, people who smoke have a worse prognosis than those who have never smoked. Furthermore, people who continue to smoke after diagnosis of head and neck cancer have the highest probability of dying compared to those who have never smoked. This effect is seen in patients with HPV-positive head and neck cancer as well. It has also been demonstrated that passive smoking, both at work and at home, increases the risk of head and neck cancer.
A major carcinogenic compound in tobacco smoke is acrylonitrile. Acrylonitrile appears to indirectly cause DNA damage by increasing oxidative stress, leading to increased levels of 8-oxo-2'-deoxyguanosine and formamidopyrimidine in DNA.. Both 8-oxo-dG and formamidopyrimidine are mutagenic. DNA glycosylase NEIL1 prevents mutagenesis by 8-oxo-dG and removes formamidopyrimidines from DNA.
Smokeless tobacco is a cause of oral cancer. Increased risk of oral cancer caused by smokeless tobacco is present in countries such as the United States but particularly prevalent in Southeast Asian countries where the use of smokeless tobacco is common. Smokeless tobacco is associated with a higher risk of developing head and neck cancer due to the presence of the tobacco-specific carcinogen N'-nitrosonornicotine.
Cigar and pipe smoking are also important risk factors for oral cancer. They have a dose dependent relationship with more consumption leading to higher chances of developing cancer. The use of electronic cigarettes may also lead to the development of head and neck cancers due to the substances like propylene glycol, glycerol, nitrosamines, and metals contained therein, which can cause damage to the airways. Exposure to e-vapour has been shown to reduce cell viability and increase the rate of cell death via apoptosis or necrosis with or without nicotine. This area of study requires more research, however. Similarly, additional research is needed to understand how marijuana possibly promotes head and neck cancers. A 2019 meta-analysis did not conclude that marijuana was associated with head and neck cancer risk. Yet individuals with cannabis use disorder were more likely to be diagnosed with such cancers in a large study published 2024.