OCCUPATIONALLY RELATED TUMORS IN TAR REFINERY WORKERS

Background: The study comprised 606 workers with tar-induced dermatosi s employed in a German tar refinery. During the period from 1946 to 19 96 they were recognized as having an occupational disease. Objective: The aim of this study was to characterize the histologic findings and the localization of the occupational dermatosis and to determine the l atency period of the carcinomas from the beginning of exposure in the tar refinery to the first occurrence of malignant skin tumors. Further more, the study aimed to check whether other skin changes were frequen tly diagnosed in addition to known tar-induced tumors. Methods: The da ta were collected retrospectively from the documents of the Employer's Liability Insurance Association. Results: Surgical removal of 4754 sk in tumors was documented up to the end of 1996 in the study. In 90% of cases the histologic diagnosis was confirmed. Among other conditions, this yielded 2490 precancerous stages, 380 squamous cell carcinomas, 218 basal cell carcinomas, and 182 keratoacanthomas. The skin turners were found mainly in the facial area, as well as on the forearms and h ands. Latency from the first exposure in the tar refinery until manife station of tar-induced dermatosis covered a period of 57 years. Conclu sion: In comparison to the general population, the ratio of squamous c ell to basal cell carcinomas was shifted toward the squamous cell carc inomas (1.7:1), Sunlight is known to be a cofactor in the pathogenesis of keratosis, squamous cell carcinomas, and basal cell carcinomas, Ho wever, the difference in location of these tumors shows that the role sunlight plays in the pathogenesis of precancerous lesions and squamou s cell carcinomas may be overvalued. The latency period from the begin ning of exposure to the manifestation of squamous cell carcinomas coul d not be evaluated because of an intervention bias as a result of prev entive excisions of precancerous lesions. The frequent occurrence of k eratoacanthomas tin 18.7% of the workers) and the early age at which t his disease became manifest relative to the general population (median , 55 years) indicate that employment in a tar refinery can primarily o r secondarily cause keratoacanthomas.