Field change and oral cancer: new evidence for widespread carcinogenesis?

Patients with oral squamous cell carcinoma (OSCC) are at risk of developing second or multiple primary cancers as a result of field cancerization in the upper aerodigestive tract. In order to quantify the incidence of field change observable in oral mucosa, 26 consecutive new (untreated) patients presenting with a unilateral OSCC (18) or a premaligant lesion (eight) underwent 'mirror image' biopsies from clinically normal-looking mucosa at corresponding anatomical sites. A total of 15 patients (58%) demonstrated histologically abnormal tissue upon microscopic examination: six showed reactive change/cellular atypia associated with chronic irritation, seven exhibited frank dysplasia, whilst two displayed carcinoma-in-situ (CIS) or microinvasive SCC. Although not statistically significant, there was an observable trend for the lateral/ventral tongue and floor of mouth to display increased vulnerability to dysplastic change.