Clinical and statistical observations were made on a group of 438 persons who had worked with aromatic
amines (
benzidine,
2-naphthylamine,
1-naphthylamine and
dianisidine) with reference to their carcinogenic properties in the urinary tract. Urinary tract
tumors developed in 68 (15.5%), with an average latent period of 22 years and 11 months. In these 68 cases, upper urinary tract
tumors were found in 16 cases, 8 of which had bilateral lesions. The average age of onset was 48.1 ranging from 24 to 79. The incidence of
tumors increased with the length of exposure to the
amines. There was no finding that smoking habit increased the incidence of
tumors in this group. Of the 49 new patients with
bladder tumor, urine cytology was positive in 24 (49.0%) and suspicious of
malignancy in 10 (20.4%), respectively. This indicated that it could be a useful screening test. Transurethral surgery was most frequently performed as an initial treatment. Recurrence occurred in 50 cases (73.5%), but 5-, 10- and 20-year-survival rates were 89.0 79.3 and 64.7%, respectively, showing a good prognosis. Malignant
tumors in other organs developed in 18 (4.1%) of the 438 workers. The incidence of such malignant
tumors was significantly higher in the workers who had been exposed to
2-naphthylamine than in others. Our data indicate that close observation is still necessary for early detection of patient with new or recurrent urothelial
carcinoma in this group.