Oral cancer or oral cavity cancer, a subtype of head and neck cancer, is any cancerous tissue growth located in the oral cavity. 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: teratoma, 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.

Signs and 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
• Early sign may be a white patch (leukoplakia) or a red patch (erythroplakia) on the soft tissues of the mouth
• 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 that do not resolve in 14 days
• Pain and paraesthesia are late symptoms.

Causes

All cancers are diseases 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. India being member of International Cancer Genome Consortium is leading efforts to map oral cancer's complete genome.

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.