Field cancerization of oral lichen planus and prognostic aspects of oral squamous cell carcinoma occuring on its background

ABSTRACT

Lichen Planus first described by Erasmus Wilson in 1869 has moved from being regarded as an innocuous benign condition to being considered as a potentially malignant disorder by the World Health Organization and is now defined as an idiopathic immune mediated mucocutaneous chronic inflammatory disease that affects the stratified squamous epithelia and the appendices. Oral lichen planus carries a very small probability of becoming malignant. The objective of the present study was to assess the long term prognostic aspects of oral squamous cell carcinoma/dysplasia and field cancerization occurring on the background of oral lichen planus in a retrospective analysis of 51 OLP patients [mean age=54 years; female, n=35; male, n=16] who between 2001 to middle of 2010 were diagnosed with OLP-related OSCC at the Department of Oral Medicine, Eastman Dental Institute and one major Head and Neck Cancer unit, University College London Hospital, United Kingdom. 1500 OLP patients were analyzed by using a computerized data base [CDR, Clinical Data Repository] and case files of Eastman Dental Institute and UCLHNHS Trust, out of which 53 patients were found to have at least one neoplastic event [intraepithelial neoplasia and/or invasive OSCC]. 2patients were excluded from the study as the case files or CDR did not have sufficient data regarding the histopathological and clinical features of oral lichen planus and/or subsequent neoplastic events. The results of the present study suggest that 3.5% [5311500] of patients with OSCC have a previous history of OLP. The mean interval between the histological diagnosis of OLP and OSCC development was 4.5 years. The observation period following the detection of the first oral malignancy was at least 2.2 years for the majority of patients. 51 oral lichen planus patients suffered a total of 137 neoplastic events [OSCC I dysplasia]. Patients with OLP and subsequent development of dysplasia I oral squamous cell carcinoma are at risk of having multiple and multifocal neoplastic events of the oral cavity and therefore worse prognosis