Effect of clinical and histologic features on time to malignancy in 224 cases of oral leukoplakia treated by surgery

Abstract

Objectives Our main purpose and research question were to analyze and quantify whether there were significant differences in the time to develop cancer among patients with oral leukoplakia (OL), comparing the more susceptible cases to those with the least susceptibility to malignancy. Materials and methods We followed 224 cases of OL after surgical or CO2 laser treatment for a mean time of 6.4 years. A Bayesian mixture cure model based on the Weibull distribution was used to model the relationship between our variables and cancer risk. In this model type, the population is considered a mixture of individuals who are susceptible or non-susceptible to developing cancer. The statistical model estimates the probability of cure (incidence model) and then infers the time to malignancy. The model was adjusted using the R-package INLA using default priors. Results Histology type (moderate or severe dysplasia) and tongue location showed hazard ratios (HR) of 3.19 (95% CI [1.05–8.59]) and 4.78 (95% CI [1.6–16.61]), respectively. Both variables increased the risk of malignant transformation, thus identifying a susceptible subpopulation with reduced time required to develop cancer, as with non-homogeneous leukoplakias. The median time for cancer development was 4 years and 5 months, with a minimum of 9 months after the diagnosis of OL and a maximum of 15 years and 2 months. Conclusions Susceptible patients with non-homogeneous leukoplakia, dysplasia, or leukoplakia in the tongue develop cancer earlier than those with homogeneous OL and those without dysplasia. Clinical relevance The novel contribution of this research is that, until now, the time it took for oral leukoplakias to develop cancer based on whether they were homogeneous or non-homogeneous, and if they have or not epithelial dysplasia, had not been comparatively described and quantified. As a final result, the time to malignant transformation in non-homogeneous and dysplastic leukoplakias is significantly shorter.

Photodynamic therapy reduced the risk of malignant transformation of oral leukoplakia: a retrospective study in an ethnic Chinese cohort

“…The proportion of malignant transformation reported in different literatures varies greatly. [19,20]. The overall malignant transformation proportion in this study was 14.6%, higher than that reported in previous literature.…”

Recurrence of Oral Leukoplakia after CO2 Laser Resection: A Prospective Longitudinal Study

“…Considering the question “does laser resection of oral leukoplakia impact recurrence and malignant transformation?”, a systematic review and meta-analysis by Pauli Paglioni et al (2020) [ 32 ] showed that surgical laser ablation of OL can reduce recurrence rates, and that this therapy has no effect on malignant transformation when compared to conventional treatments. Laser—unlike cold-knife surgery—presents a series of advantages, such as instant sterilisation of the surgical wound, better visualization, non-contact surgery and, therefore, no mechanical trauma to tissues [ 24 ].…”

“…In addition, laser surgery can be performed on an outpatient basis. The outcomes of studies investigating leukoplakias treated with CO 2 laser are highly variable, especially in terms of recurrence and malignant transformation [ 30 , 31 , 32 , 33 , 34 ].…”

Predictors of malignant transformation in oral leukoplakia and proliferative verrucous leukoplakia: An observational prospective study including the DNA ploidy status

“…This also corroborates data recently reported by Bagan et al in a group of patients with OL that underwent surgical/laser treatment, and where 9 out of 26 MT were observed in the absence of recurrence after OL treatment. 42…”