Article: Oral cancer

Oral cancer is any cancerous tissue growth located in the mouth. It may arise as a primary lesion originating in any of the oral tissues, by metastasis from a distant site of origin, or by extension from a neighboring anatomic structure, such as the nasal cavity or the maxillary sinus. Oral cancers may originate in any of the tissues of the mouth, and may be of varied histologic types: adenocarcinoma derived from a major or minor salivary gland, lymphoma from tonsillar or other lymphoid tissue, or melanoma from the pigment producing cells of the oral mucosa. Far and away the most common oral cancer is squamous cell carcinoma, originating in the tissues that line the mouth and lips. Oral or mouth cancer most commonly involves the tissue of the lips or the tongue. It may also occur on the floor of the mouth, cheek lining, gingiva (gums), or palate (roof of the mouth). Most oral cancers look very similar under the microscope and are called squamous cell carcinoma. These are malignant and tend to spread rapidly.

Known risk factors

All cancers are diseases of the DNA in the cancer cells. Oncogenes are activated as a result of mutation of the DNA. The exact cause is often unknown. Risk factors that predispose a person to oral cancer have been identified in epidemiological studies.

Smoking and other tobacco use are associated with 70 percent to 80 percent of oral cancer cases. Smoke and heat from cigarettes, cigars, and pipes irritate the mucous membranes of the mouth. Use of chewing tobacco or snuff causes irritation from direct contact with the mucous membranes.

In many Asian cultures chewing betel, paan and Areca is known to be a strong risk factor for developing oral cancer. In India where such practices are common, oral cancer represents up to 40% of all cancers, compared to just 4% in the UK.

Heavy alcohol use is another high-risk activity associated with oral cancer. There is known to be a strong synergistic effect on oral cancer risk when a person is both a heavy smoker and a heavy drinker. Their risk is greatly increased compared to a heavy smoker, or a heavy drinker alone.

Other risks include chronic irritation (such as that from rough teeth, dentures, or fillings). Some oral cancers begin as leukoplakia or mouth ulcers. Oral cancer accounts for about 8 percent of all malignant growths. Men are affected twice as often as women, particularly men older than 40/60.

Symptoms

Skin lesion, lump, or ulcer:

• On the tongue, lip, or other mouth area
• Usually small
• Most often pale colored, may be dark or discolored
• May be a deep, hard edged crack in the tissue
• Usually painless initially
• May develop a burning sensation or pain when the tumor is advanced

Additional symptoms that may be associated with this disease:

• Tongue problems
• Swallowing difficulty
• Mouth sores
• Abnormal taste
• Pain and paraesthesia are late symptoms.

Signs and tests

An examination of the mouth by the health care provider or dentist shows a visible and/or palpable (can be felt) lesion of the lip, tongue, or other mouth area. As the tumor enlarges, it may become an ulcer and bleed. Speech difficulties, chewing problems, or swallowing difficulties may develop, particularly if the cancer is on the tongue.

A tongue biopsy, gum biopsy, and microscopic examination of the lesion confirm the diagnosis of oral cancer.

Treatment

Surgical excision (removal) of the tumor is usually recommended if the tumor is small enough, and if surgery is likely to result in a functionally satisfactory result. Radiation therapy is often used in conjunction with surgery, or as the definitive radical treatment, especially if the tumour is inoperable. Chemotherapy is commonly used for more advanced tumours, often in combination with radiotherapy and surgery. Biological agents, such as Cetuximab have recently been shown to be effective in the treatment of squamous cell head and neck cancers, and are likely to have an increasing role in the future management of this condition.

Owing to the vital nature of the strutures in the head and neck area, surgery for larger cancers is technically demanding. Reconstructive surgery may be required to give an acceptable cosmtetic and functional result. Bone grafts and surgical flaps such as the radial forearm flap are used to help rebuild the structures removed during excision of the cancer.

Survival rates for oral cancer depend on the precise site, and the stage of the cancer at diagnosis. Overall, survival is around 50% at five years for more advanced cancers. Survival rates for stage 1 cancers are 90%, hence the emphasis on early detection to increase survival outcome for patients.

Following treatment, rehabilitation may be necessary to improve movement, chewing, swallowing, and speech. Speech therapists may be involved at this stage.

Complications

• Postoperative disfigurement of the face, head and neck
• Complications of radiation therapy, including dry mouth and difficulty swallowing
• Other metastasis (spread) of the cancer