Patients with a head and neck squamous cell carcinoma
(HNSCC) often develop multiple (pre)malignant lesions.
This finding led to the field 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.
Demonstration of alterations in histologically normal
tumor-adjacent mucosa from HNSCC patients supported
this hypothesis. Currently, the question has been raised
whether multiple lesions develop independently from each
other or from migrated malignant or progenitor cells.
The majority of the mucosal alterations appear to be
related to the exposure to alcohol and/or tobacco.
Moreover, almost all primary remote tumors from
HNSCC patients appear to be clonally unrelated.
Therefore, there is more evidence that field cancerization
is due to multiple independent events than to migration
of genetically altered cells.