Dye-workers/ Risk of Bladder Ca (Long Term Risk)

Occupational Bladder Cancer From Dyes Can Take Three Decades to Develop

International Journal of Urology 2001; 8 (8): 423-430.

"Re-evaluation of the latent period of bladder cancer in dyestuff-plant workers in Japan"

10/19/2001 11:15:47 AM

By David Loshak (Doctor's Guide)

The onset of bladder cancer in workers exposed to the dye-stuffs benzidine and beta-napthylamine must be surveyed more than 30 years after the initial exposure.

The latent periods of the carcinogens are longer than previously thought, warn urologists and other specialists at Hosei University and other universities in Japan.

They point out that, although it was thought to be rare for the well-known capacity of benzidine and beta-naphthylamine to cause occupational bladder cancer to develop more than 20 years after exposure, new clinical cases can in fact occur even 30 years or more later.

The specialists carried out a study to re-evaluate the latent carcinogenic period of benzidine and beta-naphthylamine in order to set the safety period after exposure for the health surveillance system.

The study investigated the incidence of bladder cancer and its histopathology over a 34-year period (1962-1996) in 236 workers in Tokyo, Japan, who had been exposed to the two dyestuffs.

Of the 236 workers, 19 (8.05 percent) were found to have bladder cancers after exposure lasting 82.0 50.2 months. The mean standard deviation latent periods until tumour development was 29.5 8.2 years from the workers' initial exposure and 20.1 10.6 years from their final exposure.

There was a negative correlation between the exposure period and the latent period from the end of exposure to cancer onset. All tumours except one were transitional cell carcinoma.

Flow cytometric analysis was performed in 11 patients, all of whom had DNA aneuploidy (more or fewer than an exact multiple of the haploid number of chromosomes).

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