Malignant transformation of oral leukoplakia treated with carbon dioxide laser: a meta-analysis

  • Yunmei Dong
  • Yuxin Chen
  • Yan Tao
  • Yilong Hao
  • Lu Jiang
  • Hongxia Dan
  • Xin Zeng
  • Qianming Chen
  • Yu Zhou
Review Article


A series of studies are dedicated to research the clinical outcomes of oral leukoplakia (OLK) treated with carbon dioxide laser (CO2 laser); however, the results vary from studies especially related to recurrence and malignant transformation. Hence, we performed this meta-analysis to precisely evaluate the malignant transformation of OLK dealt with CO2 laser and investigate the association between its malignant transformation and kinds of related risk factors, such as gender, clinical classification, long duration of leukoplakia, and degree of epithelial dysplasia and lesion regions. We performed a systematic search of the Cochrane Library, EMBASE, Pubmed, Web of Science, and SCOPUS. Single-arm rate of the overall risk of malignant transformation in OLK treated with CO2 laser was calculated using the Der-Simonian Liard method. We applied subgroup analysis to compare the risk of malignant transformation according to the degree of epithelial dysplasia, clinical type, and region of OLK. Moreover, a pooled odds ratio (OR) is calculated, along with its 95% confidence interval (CI), to compare the risk of malignant transformation according to patients’ gender, tobacco, and alcohol consumption. We used the meta package of R software for quantitative data synthesis and analysis. The rate of malignant transformation of OLK treated with carbon dioxide laser ranged from 0 to 15.38% in included studies. The overall rate of malignant transformation of OLK treated with CO2 laser is 4.50% under the random effect model [95% CI 0.0305–0.0659]. A systematic review of observational studies of OLK reported that the estimated overall (mean) malignant transformation rate was 3.5%, with a wide range between 0.13 and 34.0%. Interestingly, our result revealed that it was the male, homogeneous type, no tobacco consumption, and without alcohol-use who had a higher tendency of malignancy after laser surgery. However, this result lack statistically significant data. Generally speaking, whether oral leukoplakia patients underwent laser surgical treatment or not, it may have little effect on malignant transformation. In addition, we strongly advise that it had better not to perform CO2 laser intervention on OLK patients with the following clinical characteristics: homogeneous type, male, no tobacco consumption, and without alcohol-use. Evidence is still lacking in terms of relationship between malignant transformation and risk factors among OLK patients managed with CO2 laser. Thus, these associations should be further investigated.


Meta-analysis Oral leukoplakia Carbon dioxide laser Malignant transformation Oral dysplasia Oral potentially malignant disorders 


Funding sources

This work was supported by grants from the Nonprofit Industry Research Specific Fund of the National Health and Family Planning Commission of China (No. 201502018), National Natural Science Foundation of China (Nos. 81771086, 81470747, 81472533, and 81102060), and International Science and Technology Cooperation Program of China (No. 2012DFA31370). The funding agencies had no role in the study design, collection, analysis, or interpretation of data, writing of the report, or the decision to submit the article for publication.

Compliance with ethical standards

Conflict of interest

The authors declare no conflict of interest.


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Copyright information

© Springer-Verlag London Ltd., part of Springer Nature 2018

Authors and Affiliations

  • Yunmei Dong
    • 1
  • Yuxin Chen
    • 1
  • Yan Tao
    • 1
  • Yilong Hao
    • 1
  • Lu Jiang
    • 1
  • Hongxia Dan
    • 1
  • Xin Zeng
    • 1
  • Qianming Chen
    • 1
  • Yu Zhou
    • 1
  1. 1.State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of StomatologySichuan UniversityChengduChina

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