Oral lichen planus and malignant transformation: a longitudinal cohort study

Objective. Oral lichen planus (OLP) is associated with risk for developing oral squamous cell carcinoma (OSCC). We performed a 7-year prospective study to assess the incidence of malignant transformation of OLP among adults. Study design. Three hundred twenty-seven OLP patients, 229 women (70.0%) and 98 men (30.0%), were observed during the follow-up period. Results. During a mean follow-up of 81.7 months, 8 of 327 patients developed an OSCC in OLP areas (0.36%/y), yielding the high overall standardized incidence ratio of 17.7 (95% confidence interval [CI] 8.8-35.3). The standardized incidence ratio for OSCC was significantly higher in women [27.0 (95% CI 11.2-64.8)] than in men [11.2 (95% CI 3.6-34.9)]. Six OSCCs were well differentiated (75%) and 2 moderately differentiated (25%). Three subjects (37.5%) developed recurrences within 2 years (mean 16.1 +/- 3.5 months). Disease-free survival rate after 69.8 months was 97.3%. Conclusions. OLP was associated with a significant increase in the risk for OSCC. Close surveillance may help to reduce the morbidity of OSCC arising from OLP at 24 months. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011; 112: 328-334)