If patients with non-malignant diagnoses of study pathology (both TNFE-NBI and DRE) have been diagnosed with malignancy at or before routine follow-up, the study evaluation will be considered a false negative. If no malignancy developed within three months of the biopsy procedures, the study evaluation will be considered a true negative. (This design represents a compromise in evaluating patients with a negative endoscopy. By necessity a negative diagnosis is one of exclusion, given that complete pathologic evaluation of every patients' upper aerodigestive tract is neither ethical, practical, nor feasible in clinical practice. Precedent for this design can be found in Smith-Bindman, Chu et al. 2005)