Importance: Understanding the clinical course and malignant transformation rate of oral potentially malignant disorders (OPMDs)-including oral leukoplakia, oral erythroplakia, oral submucous fibrosis, and oral lichen planus-is crucial for early detection and improved survival rates in patients with oral cancer.
Objective: To evaluate the progression of oral cancer from OPMDs using a large US electronic medical database.
Design, setting, and participants: This retrospective cohort study used data from the University of California, San Francisco's PatientExploreR database between January 1973 and March 2024. Patients with oral leukoplakia, oral erythroplakia, oral submucous fibrosis, and oral lichen planus were identified using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, codes and keywords. Demographics, tobacco and alcohol use, HIV status, and other known risk factors for oral cancer were recorded to identify factors associated with malignant transformation. Logistic regression and descriptive analyses were used.
Exposure: Diagnosis of oral leukoplakia, oral erythroplakia, oral submucous fibrosis, or oral lichen planus.
Main outcomes and measures: Incidence of oral cancer, malignant transformation rate, median time to progression, and associations between demographics and risk factors and the development of oral cancer.
Results: Among 4 225 251 individuals in the database, 4371 were diagnosed with oral cancer (median [IQR] age, 63 [53-71] years; 2610 [59.9%] male; 0.1% of the cohort), and 110 (2.5%) had a preceding OPMD. Oral leukoplakia was found in 1124 patients, with 94 (8.4%) undergoing malignant transformation (median [IQR] time to progression, 25 [7-129] months). HIV-positive patients with oral leukoplakia were more likely to develop oral cancer (odds ratio, 3.80; 95% CI, 1.35-10.70). Of 22 patients with oral erythroplakia, 11 (50.0%) developed oral cancer (median [IQR] time to progression, 3.7 [0.2-334] months). Those who smoked tobacco with oral erythroplakia showed a higher malignant transformation rate (odds ratio, 3.75; 95% CI, 0.54-26.05). Of the 78 patients with oral submucous fibrosis, 4 (5.1%) underwent malignant transformation (median [IQR] time to progression, 36 [36-48] months). Only 1 patient with oral lichen planus developed oral cancer after 5 years.
Conclusions and relevance: This cohort study showed that OPMDs have notable but varying propensities to progress to oral cancer. Early detection and monitoring of OPMDs are crucial for improving patient outcomes. However, the risk, etiopathogenesis, and clinical presentation vary for each OPMD and should, therefore, be considered distinct diseases.