Outcome following a population screening programme for oral cancer and precancer in Japan

The purpose of this study was to evaluate the validity and outcome of an or al mucosal screening programme conducted in Japan. AII adults over the age of 40 years resident in Tokoname city were invited by letter to attend a fr ee general health screen and oral examinations annually. Twenty- to 39-year -old females were also encouraged to participate. During the years 1996-98, a total of 19 056 subjects (5885 male, 13 171 female: mean age 60.7+/-11.3 years) were examined by three types of screeners: postgraduate dental resi dents (n = 17), hospital dentists (n = 5) and general dental practitioners (n = 15). In the cohorts examined screening dentists recorded oral mucosal lesions in 783 (4.1%) subjects. Of those detected with mucosal lesions. 200 (25.5%) were referred and 137 (68.5%) attended for follow up examination i n hospital departments by specialists with full diagnostic back up faciliti es. Thirty-nine subjects were confirmed as having oral cancer or precancer (two squamous cell carcinomas, 37 leukoplakias) and 40 with lichen planus. Five false positives (3.6%) were found. Among the cases referred under othe r diagnostic labels no cancers were detected. Among those who attended for confirmation of oral cancer or precancer by a specialist, sensitivity, spec ificity and positive predictive value were 0.92, 0.64 and 0.78, respectivel y. In males with oral cancer/leukoplakia, the prevalence of smoking, drinki ng and combined habits was higher than those with lichen planus or among ne gative subjects. The sensitivity and specificity determined from this resea rch suggests that the: performance of the Japanese dentists employed in scr eening was satisfactory. An attendance of 68% for re-examination by special ists compares n ell with other reported studies measuring patient complianc e. (C) 2000 Elsevier Science Ltd. All rights reserved.