Urban legends series: oral leukoplakia

Abstract

To date, the term oral leukoplakia (OL) should be used to recognize 'predominantly white plaques of questionable risk, having excluded (other) known diseases or disorders that carry no increased risk of cancer'. In this review, we addressed four controversial topics regarding oral leukoplakias (OLs): (i) Do tobacco and alcohol cause OLs?, (ii) What percentage of OLs transform into oral squamous cell carcinoma (OSCC)?, (iii) Can we distinguish between premalignant and innocent OLs?, and (iv) Is proliferative verrucous leukoplakia (PVL) a specific entity or just a form of multifocal leukoplakia? Results of extensive literature search suggest that (i) no definitive evidence for direct causal relationship between smoked tobacco and alcohol as causative factors of OLs, (ii and iii) the vast majority of OLs follow a benign course and do not progress into a cancer, and no widely accepted and/or validated clinical and/or biological factors can predict malignant transformation, and (iv) the distinction between multifocal/multiple leukoplakias and PVL in their early presentation is impossible; the temporal clinical progression and the high rate of recurrences and development of cancer of PVL are the most reliable features for diagnosis.

MicroRNA expression profiling and functional annotation analysis of their targets associated with the malignant transformation of oral leukoplakia

“…In 2003, a systematic review indicated that OLK had a prevalence of 0.5 to 3.4% (Petti, 2003), with a reported malignant transformation rate that ranges from 0.13 to 17.5% (Holmstrup et al, 2006). Recently, epidemiological studies revealed that the malignant transformation rate for OLK varied enormously based on Arduino's study, ranging from 0.13% to 36.4% (Arduino et al, 2013). It has been reported that the risk factors associated with the malignant transformation of OLK included gender (Napier and Speight, 2008), long duration of OLK ( Van der Waal, 2010), and location on the tongue (Zhang et al, 2001).…”

“…It has been reported that the risk factors associated with the malignant transformation of OLK included gender (Napier and Speight, 2008), long duration of OLK ( Van der Waal, 2010), and location on the tongue (Zhang et al, 2001). Besides, alcohol abuse (Goldstein et al, 2010) and chewing tobacco (Arduino et al, 2013) also have been identified to be strongly associated with OLK and OSCC. Basing on the macroscopic appearance, OLK is broadly classified into two clinical subtypes, namely homogeneous and non-homogeneous ones.…”

Web‐based information on the treatment of oral leukoplakia – quality and readability

“…Leukoplakia is considered a clinical description, broadly categorised as homogeneous or non‐homogeneous, with no specific histopathological pattern . These chronic lesions have reported rates of malignant transformation ranging from 0.13% to 36.4% with a weighted average annual oral cancer incidence attributable to leukoplakia of 1.36% . This malignant transformation is more commonly seen in non‐homogeneous types of leukoplakia with for example a sevenfold increase reported in a Danish population .…”

Low expression of angiotensinogen and dipeptidyl peptidase 1 in saliva of patients with proliferative verrucous leukoplakia

“…Due to a lack of specific baseline characteristics, the PVL diagnosis is made retrospectively, based on observation of progressive clinical and microscopical characteristics of the lesions[5]. Thus, evaluation of biopsy specimens from representative areas is important in establishing the existence of epithelial dysplasia or carcinoma along with clinical evolution[15]. …”