Oral Field Cancerization: An Update

Abstract

Patients with head and neck squamous cell carcinoma (HNSCC) often develop multiple (pre) malignant lesions. This finding led to the field of the cancerization theory, which hypothesizes that the entire epithelial surface of the upper aerodigestive tract has an increased risk for the development of (pre) malignant lesions, because of multiple genetic abnormalities in the whole tissue region. Cancer begins with multiple cumulative epigenetic and genetic alterations that sequentially transform a cell or a group of cells in a particular organ. These early genetic events may lead to the clonal expansion of preneoplastic daughter cells in a particular tumor field. Subsequent genomic changes in some of these cells drive them toward the malignant phenotype. These transformed cells are diagnosed histopathologically as cancers, owing to changes in the cell morphology. Conceivably, a population of daughter cells with early genetic changes (without histopathology) remains in the organ, demonstrating the concept of field cancerization. This review explains the concept of field cancerization and various field theories along with a molecular basis of field formation.