Oral Cancer
by Ruby Ann Dollins, DDS

Oropharyngeal cancer accounts for nearly 30,000 cases of cancer (incidence of  10 per 100,000) and approximately 7,200 deaths per year in the United States, and is the sixth most common cancer worldwide. Oral cavity cancer accounts for about 17,000 of these cases per year and is more than leukemia, Hodgkin's lymphoma, brain, stomach, or ovarian cancer. The 5-year survival rate from oral carcinomas has not significantly improved in the past 30 years, remaining at approximately 50%. The 5-year survival rate for whites is approximately 55%, while for blacks it is only 31%.

The ratio of men to women diagnosed with oral cancer is 2:1 over the lifetime, although the ratio comes closer to 1:1 with advancing age (and perhaps the relationship of human papilloma virus [HPV] to oral cancer). Approximately 96% of oral cancer is diagnosed in persons over the age of 40 and more than 50% of all cancers occur in persons over the age of 65. The average age at the time of diagnosis is 63 years. However, recent evidence has emerged indicating that oral cancers are occurring more frequently in younger persons (those under 40 years old). The overall incidence of oral cancer has remained stable, relative to the occurrence of newly diagnosed cancers of all sites, with absolute numbers only slightly increasing each year.

More than 90% of these oropharyngeal cancers are squamous cell carcinomas. The other 10% are comprised of salivary gland tumors, lymphoma, sarcoma, and others. These malignancies of the oral cavity often begin as preneoplastic lesions in the form of inflammatory lesions such as leukoplakia, erythroplasia, and erythroleukoplakia. Leukoplakia is associated with tobacco and alcohol use and chronic inflammation with the risk of malignant transformation to squamous cell carcinoma (SCC) of approximately 5% to 17%. These premalignant lesions may ultimately transform to cancer; especially if they demonstrate epithelial dysplasia. If so, the rate of cancer transformation may become as high as 42%. Alternations in host immunity, inflammation, angiogenesis, and metabolism have been noted to be prominent clinical features in oral cancer.

The etiology of oral cancer is apparently multi-factorial and involves many alterations in host immunity, metabolism, angiogenesis, and exposure to chronic inflammation in a genetically susceptible individual that accumulate over time. The carcinogenic changes may be influenced by oncogenes, carcinogens, and mutations caused by chemicals, viruses, irradiation, drugs (tobacco and alcohol), hormones, nutrients, or physical irritants. The tongue is the most common site for oral cancer in both Americans men and women.

That is why it is critical to detect oral cancer as early as possible and/or prevent premalignant lesions from progressing to carcinoma. Ask your dentist for oral cancer screening at least once every year and for precautionary measures.

Submitted by Dr. Ruby Ann Dollins