title: Malignant transformation of oral submucous fibrosis in Taiwan: A nationwide population-based retrospective cohort study.
abstract: BACKGROUND
  Oral submucous fibrosis (OSF) is one of the well-recognized oral potentially malignant disorders. In this study, we investigated the malignant transformation of OSF in a Taiwanese population.
  
  
  METHODS
  A retrospective cohort study was analyzed from Taiwan's National Health Insurance Research Database. A comparison cohort was randomly frequency-matched with the OSF cohort according to age, sex, and index year. Oral leukoplakia (OL) was further stratified to evaluate for the possible synergistic effects of OSF-associated malignant transformation.
  
  
  RESULTS
  In this cohort, 71 (9.13%) of 778 cases of OSF were observed to transform into oral cancer. The malignant transformation rate was 29.26-fold in the OSF cohort than in the comparison cohort after adjustment (95% confidence intervals 20.55-41.67). To further stratify with OL, OSF with OL (52.46%; 95% confidence intervals 34.88-78.91) had higher risk of malignant transformation rate than OSF alone (29.84%; 95% confidence intervals 20.99-42.42). The Kaplan-Meier plot revealed the rate free of malignant transformation was significant over the 13-year follow-up period (log-rank test, P<.001). The mean duration of malignant transformation was 5.1, 2.7, and 2.2 years for non-OSF, OSF alone, and OSF with OL, respectively.
  
  
  CONCLUSIONS
  Oral submucous fibrosis patients exhibited a significantly higher risk of malignant transformation than those without OSF. OL could enhance malignant transformation in patients with OSF.
authors.affiliation: School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.|Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Po-Yu
authors.initials: PY
authors.lastname: Yang
authors.affiliation: Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Yi-Tzu
authors.initials: YT
authors.lastname: Chen
authors.affiliation: Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Yu-Hsun
authors.initials: YH
authors.lastname: Wang
authors.affiliation: School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Ni-Yu
authors.initials: NY
authors.lastname: Su
authors.affiliation: School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Hui-Chieh
authors.initials: HC
authors.lastname: Yu
authors.affiliation: School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.|Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Yu-Chao
authors.identifier: http://orcid.org/0000-0001-9731-2577
authors.initials: YC
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D002471:Cell Transformation, Neoplastic; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology*; D009914:Oral Submucous Fibrosis / Q000473:pathology*; D012189:Retrospective Studies; D013624:Taiwan; D055815:Young Adult
keywords: cohort study; malignant transformation; nationwide population; oral submucous fibrosis