Incidence of squamous cell carcinoma in oral lichen planus: a 25-year population-based study

Background: Oral lichen planus (OLP) is a chronic inflammatory condition of the oral mucosa. Multiple studies have shown that approximately 1% of patients with OLP will develop oral squamous cell carcinoma (OSCC), however, no study has taken a population-based multicenter approach to demonstrate this association. Our main objective was to determine the incidence of OSCC in OLP in a specific population and secondarily to assist physicians regarding appropriate long-term monitoring of patients with OLP. Methods: We conducted a population-based retrospective cohort study. Patients with OLP from 1986 through 2010 were identified using the Rochester Epidemiology Project (REP) for Olmsted County, Minnesota. For each OLP case (n = 303), we randomly selected two age- and gender-matched referents (n = 606). OLP diagnosis was established based on the World Health Organization (WHO) criteria. Medical records were reviewed for development of OSCCafter the OLP diagnosis (index date). The association between OLP and development of OSCC was assessed. Results: In total, 303 patients with incident OLP were identified; the overall incidence of OLP per 100,000 person-years was 11.4 (95% CI, 10.1–12.7). Among the OLP cohort, 7 had OSCC (incidence of OSCC, 3.1%; 95% CI, 0.6–6.4%) at 20 years after OLP diagnosis. Three OSCC cases were identified among the referents. Patients with OLP were 4.8 times more likely to have OSCC than the matched referents. The median time to OSCC development was 14.7 years earlier for the OLP cohort. Conclusions: Patients with OLP, particularly the erosive type, have an increased incidence of OSCC development and should be monitored closely.