RESUMEN
OBJECTIVE: Oral lichen planus (OLP) and lichenoid lesions (OLL) are regarded as precursor lesions of oral squamous cell carcinoma (OSCC) with potential for malignant transformation. This potential is not clear due to difficulties in diagnosis of OLP and OLL. Our aim was therefore to evaluate previously identified OLP and OLL as precursor lesions in OSCC and to identify cancer related etiological factors such as smoking and alcohol consumption. MATERIAL AND METHODS: We retrospectively reviewed all cases (total 323, comprising 164 females and 159 males) with OSCC treated at the Department of Oral and Maxillofacial Diseases and Surgery, Helsinki University Hospital during 2015. Confirmed by histopathological biopsy, 58 (17.9%) had OLP and 13 had OLL (4.0%) as precursor lesion. RESULTS: Patients with OLP were slightly older than those without it. OLP was more common in females than in males (p < .0001). TN class 1 tumors were more prevalent among patients with OLP or OLL (p = .006) and cancer relapses less common (p = .005). Smoking was less frequent in patients with OLP and OLL (p < .0001). Also alcohol abuse was less frequent among these patients (p < .001). CONCLUSION: Our findings confirm the importance of active follow-up of all patients with OLP and OLL even in patients who do not fit a traditional high-risk category for OSCC.