Carcinoma and dysplasia in oral leukoplakias in Taiwan: prevalence and risk factors.
OBJECTIVE
The issue of existence of malignancy within oral leukoplakia has seldom been addressed in Taiwan. The aims of this study were to investigate the prevalence of carcinoma and dysplasia within oral leukoplakia at the time of clinical diagnosis and to identify the associated risk factors in Taiwan.


METHODS
The prevalence rate of malignancy and dysplasia in 1046 oral leukoplakias at a university hospital was calculated. Univariate and multivariate analyses by the Mantel-Haenszel method and multiple logistic regression model were performed to examine risk factors associated with the presence of carcinoma and dysplasia within the lesions.


RESULTS
The prevalence rate of carcinoma was 12.9%. The relative risks for the presence of malignancy in leukoplakias on the tongue/floor of mouth and with nonhomogeneous appearance were 2.72- and 28.13-fold by multivariate logistic regression analysis, when compared with those on buccal mucosa and lesions having homogeneous surface (both P < .05). In contrast, patients who both smoked and chewed betel quid had a significantly lower risk for carcinoma than the abstainers (P < .05). A synergistic effect between the 2 major risk factors of clinical appearance and lesion site was evident. Nonhomogeneous leukoplakia on tongue/floor of mouth had a 43.10-fold higher risk compared to homogeneous lesions located on buccal mucosa or other sites (P < .05). However, homogeneous leukoplakia in buccal mucosa or other sites of the oral cavity still had the possibility of having carcinoma within the lesion. The prevalence of dysplasia was 45.6% among the noncancerous leukoplakias with risk factors similar to those for carcinoma.


CONCLUSIONS
Our results demonstrate that some leukoplakias contain a malignant component. Lesions with certain features are more prone to carcinoma, but no clinical attributes can bring certitude. Therefore, all oral leukoplakias should be submitted to microscopic analysis before any definite treatment or long-term follow-up.
Lee
Jang-Jaer
JJ
School of Dentistry, National Taiwan University College of Medicine, Taipei, Taiwan.
Hung
Hsin-Chia
HC
Cheng
Shi-Jung
SJ
Chen
Yi-Jane
YJ
Chiang
Chun-Pin
CP
Liu
Bu-Yuan
BY
Jeng
Jiiang-Huei
JH
Chang
Hao-Hueng
HH
Kuo
Ying-Shiung
YS
Lan
Wan-Hong
WH
Kok
Sang-Heng
SH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001114:Areca / Q000009:adverse effects; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D018289:Carcinoma, Verrucous / Q000453:epidemiology / Q000209:etiology / Q000473:pathology; D002471:Cell Transformation, Neoplastic; D005260:Female; D006801:Humans; D007972:Leukoplakia, Oral / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology; D009062:Mouth Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D016017:Odds Ratio; D011230:Precancerous Conditions / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D015995:Prevalence; D012307:Risk Factors; D012744:Sex Ratio; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology