Head and neck cancer is the sixth most common human cancer. They are located in the oral cavity in 48% of cases, and 90% of these are oral squamous cell carcinoma. The most common site for intraoral carcinoma is the tongue, which accounts for around 40% of all cases in the oral cavity. Tongue cancers most frequently occur on the posterior-lateral border and ventral surfaces of the tongue. The floor of the mouth is the second most common intraoral location. Less common sites include the gingiva, buccal mucosa, labial mucosa, and hard plate.
Oral cancers account for up to half of all malignancies in Asian countries, and this particularly high prevalence is attributed to the influence of carcinogens and region-specific epidemiological factors, especially tobacco and chewing betel quid.
The organs in our body are made up of trillions of living cells. Normal body cells grow, divide, and die in an orderly fashion. When these cells continue multiplying and grow out of control when the body doesn't need them, the result is a mass or growth, also called a tumor. These growths are considered either benign or malignant.
Benign is considered non-cancerous and malignant is cancerous. Benign tumors rarely are life threatening and do not spread to other parts of the body. Malignant tumors, on the other hand, often invade nearby tissue and organs, spreading the disease. The cells within malignant tumors have the ability to invade neighboring tissues and organs, thus spreading the disease. Thus this possibility of cancerous cells to break free from the tumor site and enter the bloodstream, spreading the disease to other organs is termed metastasis.
Oral cancer can be divided into three categories: carcinoma of the lip vermillion, carcinoma of the oral cavity proper, and carcinoma of the oropharynx.
Squamous cell carcinoma, which arises from the oral mucosal lining, accounts for more than 90% of the tumors in the oral cavity and oropharynx. Other types of primary tumors arising in this area include lymphoma, sarcoma, melanoma, and minor salivary gland tumors.
Diagnosis
Lesional biopsy
usually an incisional biopsy, but an oral brush biopsy is now available, mainly for patients with wide-spread, potentially malignant lesions and for revealing malignancy in lesions that appear benign.
Endoscopy
A lighted scope is sent down the patient's throat to see whether the cancer has spread beyond the mouth.
Imaging tests
Few tests may help to determine whether the cancer has spread:
X-rays
Computerized tomography (CT) scans
Magnetic Resonance Imaging (MRI) scans
PET (positron emission tomography) scans
Possible signs and symptoms of cancer
Patches on the lining of the mouth or tongue, usually red or red and white in color.
Painful tongue.
Mouth ulcers that do not go away.
A sore that does not heal.
A swelling in the mouth that persists for over three weeks.
A lump or thickening of the skin or lining of the mouth.
Pain when swallowing.
Loosening teeth for no clear reason.
Dentures don't fit properly.
Jaw pain or stiffness
A sensation that something is stuck in your throat.
A hoarse voice.
Risk Factors of Oral Cancer
Heavy smoking and alcohol consumption
The most important risk factor for the development of oral cancer is the consumption of regular tobacco and alcohol. As tobacco and alcohol have a synergistic effect, people who drink and are also heavy smokers have a significantly higher risk of developing oral cancer compared to others. The use of smokeless tobacco products such as gutkha and betel quid in Asian countries is responsible for a considerable percentage of oral cancer cases.
Genetic
Several studies have reported a significant familial component in the development of oral cancer. The estimates of risk in the first degree relatives of oral cancer patients vary widely and range from 1.1 to 3.8%.
Sunlight exposure
Carcinoma of the lip, predominantly on the lower lip, occurs in approximately 3,600 persons per year. Epidemiologically, these tumors behave akin to squamous cell carcinoma of the skin, and most are related to sun exposure, although chronic direct exposure to tobacco (i.e., the location where a pipe or cigarette is habitually held) is also associated with an increased risk of carcinoma of the lip.
Diet
People who consume lots of red meat, processed meat and fried foods are more likely to develop oral cancer than others.
Preneoplasia
Oral premalignant lesions of oral cavity like leukoplakia, erythroplakia, nicotine stomatitis and tobacco pouch keratosis, lichen planus, and submucous fibrosis area also considered as risk factors for developing oral cancers.
GERD (gastro-esophageal reflux disease)
People with this digestive condition where acid from the stomach leaks back up through the esophagus have a higher risk of oral cancer.
HPV infection
Human papillomavirus (HPV), particularly HPV type 16, could be another risk factor. There is an association between HPV and oral cancer, particularly HPV type 16 HPV 16 accounts for 90% to 95% of HPV-positive oropharyngeal tumors,
Prior radiation treatment
Especially in the head and/or neck area.
Exposure to certain chemicals
Like asbestos, sulphuric acid and formaldehyde.
Treatment options for oral cancer
Treatment will depend on various factors, such as where the cancer is, its stage, as well as the patient's general health and personal preferences. People may have to undergo a combination of treatments.
Surgical removal of the tumor
The tumor is surgically taken out with a margin of healthy tissue around it. If the tumor is small surgery will be minor. Larger tumors will require more extensive surgery, such as the removal of some of the jawbone or some part of the tongue. Oral cancer tends to spread to the lymph nodes in the neck in which case a neck dissection is required. Cancerous lymph nodes and related tissue in the neck are surgically removed. A radical neck dissection involves the removal of a tumor from the neck as well as additional normal tissue of at least 2 cm surrounding the tumor, as well as removing the lymph nodes from the neck.
Radiotherapy
About 40% of all types of cancer patients undergo some kind of radiotherapy. It involves the use of beams of high-energy X-rays or particles (radiation) to destroy cancer cells. Radiotherapy works by damaging the DNA inside the tumor cells, destroying their ability to reproduce.
Internal radiotherapy (brachytherapy)
often used to treat patients with early stages of cancer of the tongue. Radioactive wires or needles are stuck directly into the tumor while the patient is under a general anesthetic. The wires/needles release a dose of radiation into the tumor. Most courses of brachytherapy last from 1 to 8 days. Radiation therapy applied to the mouth may have the following side effects like dental caries, mouth sores, bleeding gums, jaw stiffness, fatigue, skin reactions, etc.
Chemotherapy
When the cancer is widespread chemotherapy is commonly used with radiotherapy. If there is a significant risk of recurrence chemotherapy combined with radiotherapy may be used. Chemotherapy involves using powerful medicines that damage the DNA of the cancer cells, undermining their ability to reproduce. Chemotherapy medications can sometimes damage healthy tissue, and patients may experience the some side-effects like fatigue, vomiting, nausea, hair loss and low immunity which get subsided after the treatment.
Targeted drug therapy (monoclonal antibodies)
this involves drugs that change aspects of cancer cells that help them grow. Cetuximab is used for some head and neck cancers - it stops the action of a protein (epidermal growth factor receptors) found in many kinds of healthy cells, but is more prevalent in the surface some cancer cells.
Cancer prevention strategies
Primary prevention
Avoidance and cessation of tobacco use
The cessation of cigarette smoking is associated with a 50% reduction of risk of developing oral cancer within 3 to 5 years.
Alcohol avoidance and cessation
Because alcohol is associated with oral cancer in a dose-dependent fashion, it is believed that cessation or avoidance of alcohol would result in a lower incidence of oral cancer.
Avoidance of HPV infection
Association with HPV 16–positive squamous cell carcinoma of the head and neck is independently associated with several measures of sexual behavior and exposure to marijuana, although not with cumulative measures of the usual risk factors of tobacco smoking, alcohol drinking, and poor oral hygiene. Prevention of exposure to high-risk Human Papilloma Virus (HPV) types by prophylactic vaccination may prove to be most efficient and feasible option for the prevention of pre-cancerous and cancerous lesions
Dietary changes and dietary supplements
Several studies have shown an inverse association of fruit intake and the development of oral cancer, particularly in those who use tobacco. Fiber, in the form of vegetable intake, has similarly been shown to be associated with a decreased risk of oral cancer. It is estimated that intake of fruits and vegetables may lower the risk of development of oral cancer by 30% to 50%.
Sun avoidance and sunscreen use
The majority of cases of carcinoma of the lip occur on the lower lip, which has greater sun exposure than the upper lip. While tobacco has been strongly associated with lip cancer, sun exposure may be a factor as well. Sunscreen use has been associated with a lower incidence of lip cancer. Some studies have shown a decreased risk of lip cancer associated with the daily use of lip protection (mostly colored lipstick). Lip balm with sun protection should provide preventive measures.
Secondary Prevention
Oral cancer screening: Oral visual inspection is a suitable test for oral cancer screening. It is even possible to train para medical staff to perform the oral cancer-screening test. The primary health centres should also be trained to conduct oral examination for early detection and for providing health education.
Conclusion
Since oral cancer is the sixth largest group of malignancies worldwide, early diagnosis and treatment is of vital importance. Seventy percent of oral cancers appear from premalignant lesions. The major risk factors for these diseases are tobacco, dietary habits, inadequate physical activity, alcohol consumption and infections due to viruses. The greatest impact to reduce the burden of cancer comes from primary prevention. Prophylactic vaccinations against HPV infection are also useful strategies for the prevention of cancerous lesions.
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