[Occupational uroepithelial cancer: current status in Wakayama city and clinical study]

According to the records of Wakayama Labor Standard Office, at least 1,085 workers had been exposed to benzidine or beta-naphthylamine in the dyestuff factories in Wakayama City. By October 1988, 101 of them (9.3%) were confirmed to have urinary tract tumors. Including 2 other cases exposed in Osaka, a total of 103 cases of occupational uroepithelial cancer were studied here clinically. Site of tumors was bladder in 91 cases, renal pelvis in 2, ureter in 5 and papillomatosis type in 5. The age at the time of diagnosis ranged from 25 to 87 years with a mean of 53.8 years. The average latent period was 22.7 years, but the older the age of the worker at the start of exposure, the shorter was the latent period. In Wakayama, the proper system of healthy examination for chemical workers using urinary cytology was begun in 1970. Since then, more tumor cases have been discovered in comparison to the patients admitted with subjective symptoms of hematuria. The effectiveness of this group examination was significant in the incidence of total cystectomy in surgical treatment and in survival rate. In the comparative study between the groups of patients with occupational and spontaneous bladder cancer, the average age at diagnosis in the former was about ten years younger. Although the histological grade of tumor was not different between the two groups, the incidence of total cystectomy was lower and the survival rate was significantly higher in the occupational group.