What is mouth cancer?

Early detection and treatment of oral cancer is essential for increasing survival rates. The 5-year survival rate has not improved significantly in the past 30 years. For all stages combined, about 82% of persons with oral cavity and pharynx cancer survive 1 year after diagnosis. The 5-year and 10-year relative survival rates are 59% and 48%, respectively. In whites, the survival rate is approximately 55%, while in blacks, it is only 31%. Oral cancer is the sixth most common cancer worldwide. In the US, it accounts for an estimated 35,000 cases of cancer and about 7,600 deaths annually. Oral cavity cancer constitutes about 17,000 of these cases per year and is more common than cervical or ovarian cancer, Hodgkin’s lymphoma, or leukemia.

The average age at diagnosis is 63 years. Approximately 96% of oral cancers are detected above the age of 40, and more than 50% of all cancers occur in persons older than 65. However, recent evidence indicates oral cancers are becoming more prevalent in people younger than 40 years.The lifetime ratio of males to females receiving an oral cancer diagnosis is 2:1, although advancing age changes that ratio to nearly 1:1. However, oral cancers are twice as common in males compared to females.  The overall incidence of oral cancers has stabilized, relative to the occurrence of newly diagnosed cancers of all oral sites, with absolute numbers increasing only slightly each year.  More than 90% of these oral-pharyngeal cancers are squamous cell carcinomas (SCC). The remainder includes salivary gland tumors, lymphoma, and sarcoma.

Often, these malignancies begin as preneoplastic inflammatory lesions, such as leukoplakia, erythroplasia, and erythroleukoplakia. Leukoplakia is a common oral lesion, appearing as a highly phenotypically variable white patch, and may be associated with tobacco and alcohol use, as well as chronic inflammation. When these and other risk factors are present, the risk of malignant transformation to SCC may approach 17%.These leukoplakia (or other premalignant lesions) may become cancerous, especially if they demonstrate epithelial dysplasia. If epithelial dysplasia is diagnosed, the rate of cancer transformation may become as high as 42%. Alterations in host immunity, inflammation, angiogenesis, and metabolism have been noted as prominent clinical features in oral cancers.