Characterization of Malignant Transforming Oral Lichen Planus, A 13-Year Retrospective Clinicopathological Study in A Tertiary Center and Review of the Literature

Background: Oral squamous cell carcinoma (OSCC), the most common of all mucosal malignancies presenting in the head and neck (\u3e90%), is estimated internationally to represent ~2% of the world’s malignant neoplasms. 1-3 In 2005, the World Health Organization (WHO) recognized oral lichen planus (OLP) as a premalignant condition. 4 The characteristics of OLP undergoing malignant transformation, and the risk factors that contribute to this transformation are understudied. Method: An Institutional Review Board (IRB) approved a retrospective review of electronic health records (EHR) of oral medicine patients between 2005 and 2018 was performed using ICD9 and ICD10 diagnosis codes for OLP and OSCC. Cases with both diagnoses were retrieved, and clinical notes, histopathology reports, laboratory studies and demographic records were reviewed. Result: 42 patients’ medical records met the inclusion criteria of the study; 29 females (69%) and 13 males (31%). Ages of patients ranged from 41 to 97, with an average age of 75.12 (SD = 12.64). Participants self-reported history of smoking (n = 19) or non-smoking (n = 23) and alcohol use were (no: n = 19; former: n = 1; occasionally: n = 20; often: n = 2). A multilinear regression analysis assessed the effect of smoking, OLP therapy, candida, and prophylaxis antifungal therapy on the prediction of the time between OLP and OSCC diagnosis. The average time between the diagnosis of OLP and the development of OSCC was 7.17 years (SD = 6.58). The time period in years between OLP and OSCC diagnoses increased by 4.2 years in patients who received topical pharmacological therapy for OLP (p= .017), and increased by 4.3 years in patients who received prophylaxis antifungal therapy for OLP (p=.014). As contrary, participants who had candida overgrowth had a shorter time in years between OLP and OSCC diagnoses by 4.5 years (p=.0008), and smokers had a shorter time in years between OLP and OSCC diagnoses by 3.6 years (p=0.31). The most frequent location of OSCC was the tongue (n = 25), followed by the buccal mucosa (n = 9), gingiva (n = 5), the retromolar trigone (n = 2) and the palate (n = 1). The majority of patients, 52% (n= 22), had stage I cancer. 19% of patients (n= 8) had stage II cancer. 85.3% (n = 29) of patients (n = 34) had at least a 5-year survival following diagnosis of OSCC. Conclusion: In this population, four predictors significantly contributed to the length of time between OLP and OSCC diagnoses. It appears that the management of OLP using topical pharmacological therapy delayed the progression of OLP lesions to OSCC . Additionally, the result of this study also suggests that candida infection might play a detrimental role in the progression of OLP lesions as patients who had candida overgrowth had a shorter time in years between OLP and OSCC diagnoses. Additional prospective studies are needed for a better understanding of the disease pathogenesis, and the malignant transformation potential of these lesions. It will also allow the development of novel targeted therapies for management of OLP