Oral cancer, also known as oral cavity cancer, tongue cancer or mouth cancer, is a cancer of the lining of the lips, mouth, or upper throat. In the mouth, it most commonly starts as a painless red or white patch, that thickens, gets ulcerated and continues to grow. When on the lips, it commonly looks like a persistent crusting ulcer that does not heal, and slowly grows. Other symptoms may include difficult or painful swallowing, new lumps or bumps in the neck, a swelling in the mouth, or a feeling of numbness in the mouth or lips. Risk factors include tobacco and alcohol use. Those who use both alcohol and tobacco have a 15 times greater risk of oral cancer than those who use neither. Other risk factors include betel nut chewing and sun exposure on the lip. HPV infection may play a limited role in some oral cavity cancers. Oral cancer is a subgroup of head and neck cancers. Diagnosis is made by sampling (biopsy) of the lesion, followed by an imaging workup (called staging) which can include CT scan, MRI, PET scan to determine the local extension of the tumor, and if the disease has spread to distant parts of the body. Oral cancer can be prevented by avoiding tobacco products, limiting alcohol use, sun protection on the lip, HPV vaccination, and avoidance of betel nut chewing. Treatments used for oral cancer can include a combination of surgery (to remove the tumor and regional lymph nodes), radiation therapy, chemotherapy, or targeted therapy. The types of treatments will depend on the size, locations, and spread of the cancer taken into consideration with the general health of the person. In 2018, oral cancer occurred globally in about 355,000 people, and resulted in 177,000 deaths. Between 1999 and 2015 in the United States, the rate of oral cancer increased 6% (from 10.9 to 11.6 per 100,000). Deaths from oral cancer during this time decreased 7% (from 2.7 to 2.5 per 100,000). Oral cancer has an overall 5 year survival rate of 70% in the United States as of 2026. This varies from 88% if diagnosed when localized, compared to 69% if it has spread to the lymph nodes in the neck, and 37% if it has spread to distant parts of the body. Survival rates also are dependent on the location of the disease in the mouth.
Signs and symptoms The signs and symptoms of oral cancer depend on the location of the tumor but are generally thin, irregular, red and/or white patches in the mouth. The classic warning sign is a persistent rough patch with ulceration, and a raised border that is minimally painful. On the lip, the ulcer is more commonly crusting and dry, and in the pharynx it is more commonly a mass. It can also be associated with loose teeth, bleeding gums, persistent ear ache, a feeling of numbness in the lip and chin, or swelling. When the cancer extends to the oropharynx (back of the throat), there can also be difficulty swallowing.
Causes
The main causes of oral cancer are alcohol and tobacco (smoked or chewed). The risk is especially high when a person regularly uses both. The more is consumed of either the higher the risk of developing oral cancer. Like all environmental factors, the rate at which cancer will develop is dependent on the dose, frequency and method of application of the carcinogen (the substance that is causing the cancer). Aside from tobacco and alcohol, other carcinogens for oral cancer include viruses (particularly HPV 16 and 18), radiation, and UV light.
Tobacco Tobacco is the greatest single cause of oral and pharyngeal cancer. Using tobacco increases the risk of oral cancer by 3 to 6 times and is responsible for around 40% of all oral cancers. Smokeless tobacco (including chewing tobacco, snuff, snus) also causes oral cancer. Cigar and pipe smoking are also important risk factors. 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. Use of marijuana has currently not been shown to be associated with head and neck cancer risk.
Alcohol Drinking alcohol is a major cause of oral cancer. It is responsible for about 20% of global oral cancer cases. The more alcohol is consumed regularly the higher the risk, but light to moderate drinking still somewhat increases the chances of getting oral cancer. The risk is especially high when both alcohol and tobacco are used. It has been controversial if the use of alcohol-based mouthwashes increases oral cancer risk. As of 2024, there is some limited evidence supporting that the use of mouthwashes containing alcohol can increase the occurrence of oral cancer in some cases. There are complex interactions between alcohol content, usage patterns, reduction of oral pathogens, poor oral hygiene, smoking, and drinking which make any broad conclusion very tenuous in the absence of rigorously controlled studies. In subgroup analyses, various combinations of smoking, drinking alcohol, poor oral hygiene, and using mouthwash several times a day for 35 years or more significantly increased risk. Although alcohol is necessary to dissolve some active antimicrobial agents, Rao et al. advise reducing the alcohol content of mouthwashes if possible.
Human papillomavirus
Infection with human papillomavirus (HPV), particularly type 16, is a cause of oropharyngeal cancer (tonsils, base of tongue). However, its role in the genesis of oral cavity cancers is a matter of debate. A 2023 meta-analysis observed that the HPV was present 6% of all oral cavity cancer cases, however without establishing a role of this virus in the oncogenesis of these tumors. The authors even reported that some base of tongue tumors may have been misclassified as oral cavity tumors, therefore mistakenly increasing the rate of HPV-positive oral cavity cancers.
Betel nut
Chewing betel quid (paan) and Areca nut-based products is known to be a strong risk factor for developing oral cancer even in the absence of tobacco. It doubles the risk of oral cancer 2.1 times and when chewed with additional tobacco in its preparation (like in gutka), there is an even higher risk. In India where such practices are common, oral cancer represents up to 40% of all cancers, compared to just 4% in the UK.
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