title: Malignant transformation and natural history of oral leukoplakia in 57,518 industrial workers of Gujarat, India.
abstract: In Gujarat, India, 6718 industrial workers, over 35 years of age, with oral leukoplakia (confirmed clinically and microscopically), were studied. After 2 years, 4762 (71%) of the individuals were re-examined. The buccal mucosa was the most common site of occurrence; 98.3% of these individuals had oral habits, with smoking alone or smoking in combination with "pan" or "supari" chewing accounting for 74.9% of the habit forms. Six individuals (0.13%) with oral leukoplakia developed oral carcinomas within 2 years. This incidence of malignant transformation was equivalent to 63/100,000 per year, which far exceeds that of new oral cancers expected even in high-risk populations. While 57.3% the leukoplakic lesions remained unchanged during a 2-year interval, 31.6% disappeared and 11% had an altered appearance. This study confirmed the precancerous nature of oral leukoplakia.
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007194:India; D007972:Leukoplakia, Oral / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010947:Plants, Toxic; D011230:Precancerous Conditions / Q000453:epidemiology; D012306:Risk; D012907:Smoking / Q000150:complications; D014030:Tobacco, Smokeless