Most oral cancers develop from precancerous or potentially malignant lesions in the tissue lining the inside of the mouth.
Such a lesion results in atypical changes to the mouth lining, known as the oral mucosa or epithelium. After a biopsy, patients with a precancerous oral lesion will be told they have “epithelial dysplasia.” This diagnosis means they have abnormal cells (the cells are morphologically altered in form and structure) but those cells are confined to the mucosal lining. Once the cells invade below the mouth lining, the situation has progressed from a potential malignancy to oral cancer.
Overall, less than 10 percent of patients advance to cancer from a precancerous lesion. However, some patients have a significantly higher risk of progressing to cancer, particularly those people with a diagnosis of severe epithelial dysplasia. All patients with a history of precancerous lesions need to be followed closely by a medical expert.
The most common clinical presentations of precancerous lesions are:
Leukoplakia describes white patches whose cause cannot be explained. If the white patch cannot be wiped off with gauze, it is considered suspicious. These are the most common precancers and carry the smallest chance of developing into cancer.
These are unexplained reddish patches. While rarer than white patches, lesions with a red component have the highest potential for becoming malignant.
Red and white patches can appear combined.
Oral precancers are usually asymptomatic and painless so the patient is unaware of the lesion's presence.
For this reason, it is important to get a regular examination by a qualified clinician to detect any abnormal tissue changes. If a person detects a lesion (or a sore) that does not heal within 14 days they should be examined by a qualified clinician. Early detection of precancerous lesions is critical to preventing a malignant transformation. As part of an individual treatment plan, a genetic study could determine patients at risk for progression of precancer to cancer as well as the risk of metastasis, tumor recurrence, and additional primary tumors.