Association of Clinical and Molecular Features of Previously Treated Tumour Sites with Risk for Second Oral Malignancy

Second oral malignancy (SOM) is a common occurrence for patients with oral cancers, contributing to low 5-year survival rates for this disease (~60%). Oral mucosal changes at previously treated cancer sites are common and can be defined clinically by white-light examination and toluidine blue staining, and molecularly by loss of heterozygosity (LOH) analysis. To determine the role of such changes in predicting SOM, this study analyzed data collected from 194 oral squamous cell carcinoma patients in follow-up after treatment of which 31 (16%) developed SOM. Two features were shown to be associated with elevated risk of SOM: the clinical presence of an oral premalignant lesion (OPL) (P