Table 1.

Clinical risk assessment criteria

Study Group	Case Definitions
Low Risk for malignancy	Leukoplakia. Adherent white patch on any oral mucosal surface which has no apparent explanation or etiology (i.e., frictional trauma, infection). Such lesions will NOT have associated erythroplakia, ulceration, erosion, or submucosal extension / induration.
High Risk for malignancy	Any of the following features, alone or in combination. May be associated with other high-risk signs and symptoms such as history of oral cancer or other cancer with metastatic potential, regional adenopathy, submucosal extension / induration, ulceration. Leukoplakia Any adherent white patch on any oral mucosal surface which has no apparent explanation or etiology but DOES HAVE associated, ulceration, erosion, or submucosal extension / induration.. Erythroplakia: Red patch on any mucosal surface which has no apparent explanation or etiology. Erythroleukoplakia: Mixed red and white patch on any oral mucosal surface which has no apparent explanation or etiology Ulceration: Any break in the oral epithelial surface which has no apparent explanation or etiology. This may or may not be symptomatic and may be of undetermined duration. There is increased risk for malignancy with increased duration.
Known Cancer	Biopsy-proven oral squamous cell carcinoma prior to study enrollment