Field cancerization in oral lichen planus

Background The concept of field cancerization describes the tendency of patients with premalignant and malignant lesions of head and neck mucosal sites to develop multiple carcinomas of the upper aerodigestive tract. Here we address whether this concept should be extended also to patients affected by oral lichen planus (OLP), an inflammatory disorder associated with an increased risk of cancer development. Methods Data from a cohort of 45 patients with OLP who subsequently developed severe dysplastic changes and/or oral squamous cell carcinoma were retrospectively reviewed. Patients who presented more than one oral neoplastic event were considered for further data analysis as regards incidence, localization, management and prognosis. Results Twenty (44.4 %) patients were affected by one single neoplastic event while 25 (55.6 %) developed multiple and often multifocal oral dysplastic and/or malignant events. In most cases, a careful surveillance programme led to diagnosis and effective treatment of oral neoplasias at an early intraepithelial and microinvasive stage, leading to long-term survival. In some patients, however, additional primary tumours occurred suddenly with rapid invasion, leading to advanced stage diagnosis and poor prognosis. Overall, three patients (12 %) died due to malignant oral disease. Conclusions Patients with OLP and subsequent development of dysplasia/ oral squamous cell carcinoma are at risk of having multiple and multifocal neoplastic events of the oral cavity, a phenomenon which parallels the concept of field cancerization of traditional head and neck cancers. If detected at an early stage, these neoplasias can be managed with superficial and complete resection. However a small number of patients have loco-regional tumour spread despite a standard surveillance protocol.