I. What is oral cancer?
Oral cancer in a broad sense refers to malignant tumors that occur in the oral cavity. It includes tongue cancer, gum cancer, palate cancer, central jaw cancer, floor of mouth cancer, oropharyngeal cancer, lip cancer, salivary cancer and maxillary sinus cancer, as well as cancers of skin and mucous membrane on the face. Among them, tongue cancer is the most common. Wang Zhiqi, Head and Neck Surgery Department, Shandong Cancer Control Institute
II. Incidence of oral cancer
In Southeast Asia, the incidence and mortality rate of oral cancer are very high. In Taiwan, oral cancer is the third most common malignant tumor in the whole body, and the incidence rate of oral cancer in India is reported to be the highest in the world. In the United States and some other countries in the world, the incidence of oral cancer has been increasing year by year. However, the incidence rate of tongue cancer has been increasing rapidly in recent years, accounting for nearly half of all oral cancers; secondly, there is a trend of younger age of oral cancer, and young patients aged 20-30 are not uncommon.
Oral cancer tends to occur in men, but with the accelerated pace of society, diet and social factors, the number of female patients has increased year by year in recent years. Oral cancer can occur at any age, with 40-60 years old as the peak incidence. Tongue cancer is the most common in China, and gum cancer is the second most common.
Who is prone to oral cancer?
The external carcinogenic factors of cancer include physical, chemical and biological factors, which work together with the intrinsic factors such as immunity, genetics and metabolism to transform normal cells into malignant cells and cancer occurs.
1.Tobacco and alcohol and local diet
The carcinogenic factor in tobacco is mainly the chemical benzopyrene, and the possibility of cancer is much higher in long-term smokers than in non-smokers; smoking pipes, cigars or chewing tobacco mainly lead to oral cancer, and cigarette butts touching the lip area are prone to lip cancer, which is related to long-term burns. Alcohol increases the risk of oral cancer due to its toxicity to normal cells and damages the liver’s suppressed immunity, and its incidence can rise with the increase of alcohol consumption. The risk of oral cancer is higher for those who are addicted to alcohol and tobacco, which is two to three times higher than those who are addicted to tobacco or alcohol alone. It is generally believed that those who smoke more than 1 pack/day or drink more than 25 grams/day are much more likely to develop oral cancer or oropharyngeal cancer for up to 10 years than non-smokers or alcohol drinkers.
The habit of betel nut chewing and tobacco chewing among residents in the south of China and some regions in South and Southeast Asia is also one of the factors of higher incidence of oral cancer in the region.
2.Chronic stimulation and injury
If there are sharp cusps, residual roots, residual crowns, crests and bad restorations in the oral cavity, the corresponding parts may become cancerous after long-term chronic stimulation, especially tongue cancer and buccal cancer. Statistics show that 1/5 of oral cancer patients have sharp irritation factors at the cancerous site. In addition, the long-term chronic inflammatory stimulation of poor oral hygiene may also become a cancer-promoting factor.
3.Ultraviolet and ionizing radiation
Outdoor workers, who are exposed to direct sunlight for a long time, have higher incidence of lip cancer and skin cancer. Ionizing radiation can cause changes in DNA of genetic material, activate tumor genes and lead to cancer. Radiation treatment in the oral and maxillofacial areas of the radiation zone can also occur as a second primary cancer.
4.Viral factors: Studies have found that squamous carcinoma may be related to human papilloma (HPV) virus
5.Intrinsic factors: including gene mutation, genetic factors, immune status, endocrine factors and neuropsychiatric factors.
6.Nutritional factors.
Such as vitamin A1 and B2 and deficiencies of trace elements iron, zinc and arsenic can increase the body’s sensitivity to carcinogens. In addition, chronic hepatitis, liver cirrhosis and viral infections, which lead to low immunity of the body, have a certain relationship with the occurrence of oral cancer.
Pre-cancerous lesion and pre-cancerous state of oral cancer
Pre-cancerous lesion: It is a kind of tissue with morphological changes, which has a greater possibility of developing cancer than the corresponding normal tissues.
Pre-cancerous state: a general state that significantly increases the risk of cancer development. Both of them should be given full attention because they are both capable of developing cancer, only the incidence and timing are different.
The most common precancerous lesions of the oral and maxillofacial surfaces should include
1.White spots
White spots of oral mucosa is a recognized precancerous disease, which can be manifested as flat white lesions, or wrinkled paper-like, granular, or even ulcerated. It occurs in cheek and lip mucosa. The cancer rate of oral mucosal leukoplakia can be more than 5%.
2.Erythema
Oral mucosal erythema has been regarded as a disease with higher cancer rate than white spots in recent years. Although the incidence of erythema is much lower than that of leukoplakia, its risk is not negligible, and the cancer rate is as high as 80%. The tongue, floor of the mouth and lateral pharynx are considered high risk areas for erythema.
The most common precancerous states of oral and maxillofacial
1.Flat moss: Flat moss is a common oral mucosal disease, and its cancer rate is about 1-10%, with vesicular type, atrophic type and plaque type more prone to malignant change, and the most common parts are buccal, tongue and floor of mouth mucosa.
2.Submucosal fibrosis of oral cavity.
Oral submucosal fibrosis is thought to be related to betel nut chewing, and 1/3 of them can eventually develop into cancer. The main manifestations are burning pain when eating, dry mouth and atrophy of oral mucosa. It is commonly found in both sides of the buccal mucosa, lips, tongue and other parts.
V. What are the manifestations of early oral cancer?
1. New organisms appear on the oral and maxillofacial surfaces, such as granular, cauliflower-like or early ulceration and pain.
2.Unexplained pain and numbness in tongue, cheek and other parts.
3.Unexplained pain, rapid loosening and loss of teeth, etc.
4.The ulcers in the mouth or face do not heal in January.
5.White or red patches and infiltrated hard lumps of oral mucosa that cannot be explained.
VI. What should be done if oral cancer is found? What is the prognosis?
Those who find oral cancer or suspect to have oral cancer should seek medical treatment as early as possible and go to regular hospitals in time. At present, the five-year survival rate of oral cancer is about 60%, and the overall prognosis of early oral cancer is higher than this rate. The earlier the stage of tumor, the higher the degree of differentiation, the more timely and standardized the treatment, the better the prognosis. Overall, the prognosis of lower lip cancer is the best, and many patients are cured by surgery. There are more early metastases of tongue cancer and the prognosis is slightly worse.
7.How to prevent oral cancer?
1.Understand the factors related to the development of oral cancer and recognize the risk of oral cancer.
2. Pay attention to the balance of nutrition, quit smoking and alcohol, treat the residual root and crown in time and remove the bad stimulus.
3. Pay attention to the oral ulcers that do not heal for a long time (more than 2 weeks). Actively deal with and treat precancerous diseases.
4. Early detection, early diagnosis and early treatment, and insist on regular examination.