The latter carcinogens are chemically related to nicotine. Four case-controlled studies have shown an association between the use of oral snuff and the development of oral squamous cell carcinoma. Tumors develop at the site where the snuff is lodged, primarily at the gingivobuccal sulcus. Such tumors have been observed in particular in elderly women in the southern United States, where snuff dipping has been a common practice. The latent period for the development of cancer may exceed 35 years.
Treatment depends on the stage of the tumor and the pattern of tumor spread.
Early lesions are confined to the mucosa or submucosa, whereas advanced-stage tumors may invade the mandible, maxilla, tongue, or oropharynx. In one study, the incidence was 50 percent in a group of health care professionals and 20 percent in a group representing the general population. These lesions occur singly or in groups and usually heal within 10 to 14 days without scarring. Another variant consists of grouped herpetiform ulcerations that are not caused by herpes simplex virus. No single microbial agent has been established as the cause of aphthous stomatitis, although various organisms may play a secondary role.