The Maxillofacial Center for Diagnostics & Research

Tables 21: Follow-up Studies of
Oral and Laryngeal Leukoplakia

[Click here to return to listing of epidemiology tables]


The following lists and tables of data have been compiled by Research Advisors of The Maxillofacial Center in the hopes that it will be useful to health professionals seeking information pertaining to diseases of the oral and maxillofacial region. References to the source of the data can be found by clicking on the "References" button associated with the table.  

Contents:

Table 21a:  Malignant transformation rates for oral leukoplakia.
Table 21b
:  Malignant transformation rates for oral carcinoma in situ & severe dysplasia.
Table 21c
:  Malignant transformation rates for laryngeal CIS & severe dysplasia.
Table 21d
:  Listing of the oral premalignancies, ranked by risk of cancer development.


Prevalence of Oral Leukoplakia

Table 21a: Malignant transformation rates (%) of the largest leukoplakia follow-up studies from Europe and the United States, ranked by sample size (modified from Bouquot JE, Whitaker SB. Quint Internat 1994; 25:133-140).

[Click here to return to Table of Contents]  

Author(s)

Country # Pts. Cumulative Years of Follow-up Malignant
Transformation
Potential
Annual
Cancer
Rate
Einhorn, Wersall (1967) Sweden 782

9,149 p-y (mean: 11.7yrs)

4.0% 0.34%
Banoczy (1977) Hungary 670

6,566 p-y (mean: 9.8 yrs)

6.0 0.61
Bouquot, et al (1988) * U.S.A. 463

6,720 p-y (mean: 11.8 yrs)

10.3 0.82
Roed-Peterson (1971) Denmark 331

1,423 p-y (mean: 4.3 yrs)

3.6 0.82
Leonardelli, Talamazzi (1950) Italy 268

1,340 p-y (mean: n/a)

19.8 0.40
Silverman et al (1984) U.S.A. 257

1,850 p-y (mean: n/a)

17.5 0.24
Pindborg, et al (1968) Denmark 248

918 p-y (mean: 3.7 yrs.)

4.4 1.20
Maerker, Burkhardt (1978) Germany 200

1,000 p-y (mean: 5.0 yrs)

12.0 2.40
Kramer, et al (1970) England 187

935 p-y (mean: n/a)

4.8 0.96
Sturgis, Lund (1934) U.S.A. 143

715 p-y (mean: 5.0 yrs)

13.0 2.37
Total 3,549

30,616 person-years

8.1% **1.07%

        * includes 13 cases from the pharynx.
       ** weighed for different sample sizes; many studies include a disproportional sampling of high risk lesions; the overall malignant
             transformation rate is usually considered to be 4-6% when all lesions are assessed.


Table 21b: Malignant transformation rates (%) for oral carcinoma in situ and/or severe epithelial dysplasia, ranked by sample size. Lesions appeared clinically as red, white or combined red and white macules, i.e. not all were pure erythroplakias. Cancers not arising from the site of the precancer are excluded (modified from Bouquot JE, Ephros H. Prac Perio Aesth Dent 1995; 7:59-68).

[Click here to return to Table of Contents]  
Author(s) Country # Patients Cumulative Follow-up Time Malignant Transformation Rate
Bouquot, et al (1988) @ U.S.A. 32 @@

346 yrs (m=10.8 yrs)

15.6%
Banoczy, Csiba (1976) Hungary 23

145 yrs (m=6.3 yrs)

21.8
Silverman, et al (1984) U.S.A. 22

162 yrs (m=7.4 yrs)

36.0
Mincer, et al (1972) U.S.A. 16

48 yrs (m=3.0 yrs) *

18.8
Vedtofte, et al (1987) Denmark 14

55 yrs (m=3.9 yrs)

35.7
Amagasa, et al (1985) Japan 12 @@

120 yrs (m=10.0 yrs)

50.0
Lumerman, et al (1995) U.S.A. 7

11 yrs (m=1.5 yrs)

14.3%
TOTAL 126

887 years (m=7.1 yrs)

26.3% **

    # sum total of time which lesions were collectively followed (mean follow-up times are in parentheses)
    @ the only population-based study; represents middle-class whites
@@ includes only carcinoma in situ cases
    * assumes an average follow-up time of 3 years (range=1-8 years); data not available from the report
   ** statistically weighed for different follow-up time periods and sample sizes


Table 21c: Malignant transformation rates (%) for laryngeal carcinoma in situ, as determined by all English language follow-up studies published to date, ranked by sample size (modified from Bouquot JE, Gnepp DR. Head Neck 1991; 13:488-497).

[Click here to return to Table of Contents]  
Country (Date) # Patients Malignant Transformation Rate (%)
United States (1971) 203 ## 15.8
United States (1979) 81 ## 17.0
United States (1952) 29 ## 3.5 *
United States (1977) 28 ## 7.1
Germany (1981) 27 # 63.0 **
United States (1976) 26 ## 4.0
Germany (1963) 20 ## 90.0 **
Norway (1982) 20 # 25.0
United States (1960) 18 # 11.1
United States (1963) 16 # 33.3 **
United States (1973) 12 # 7.3
Germany (1989) 6# 40.0
Total, Treated Cases 486 29.0% ***
Total, Untreated Cases 53 60.0% ***

    * includes only cancers developing in the anatomic area of the previously recorded dysplastic lesions
  ** includes only untreated cases of carcinoma in situ and severe epithelial dysplasia
*** weighed for different sample sizes, excludes untreated cases
    # includes all epithelial dysplasias: mild, moderate and severe dysplasia, and carcinoma in situ
  ## includes only severe epithelial dysplasias and carcinomas in situ


Table 21d: Precancerous lesions of the oral, pharyngeal and laryngeal mucosa, clinical terms only (modified from Speight PM, Farthing PM, Bouquot JE. Curr Diag Path 1996; 3:165-177).

Disease Name Malignant Tranformation Potential
Proliferative verrucous leukoplakia (PVC) ******
Nicotine palatinus in reverse smokers # *****
Erythroplakia *****
Oral submucous fibrosis *****
Erythroleukoplakia ****
Granular leukoplakia ****
Laryngeal keratosis ***
Actinic cheilosis ***
Smooth, thick leukoplakia **
Lichen planus (erosive forms) **
Smooth, red tongue of Plummer-Vinson disease **
Smokeless tobacco keratosis *
Smooth, thin leukoplakia +/-

                 # reverse smoking: smoking with the lit end of the cigarette in one's mouth