Screening for bladder cancer in high-risk groups: delineation of the problem

Article Abstract:

Primary prevention, the avoidance of exposure and prevention of disease, is the principal strategy for preventing occupational diseases. For nearly 100 years various chemicals and occupations have been implicated in the development of bladder cancer. Numerous groups of exposed workers and community residents have sought medical advice concerning screening for bladder cancer. In 1977, a conference was held to determine what benefit, in terms of diminished morbidity or mortality, could be derived from any bladder cancer screening effort. Several questions were raised during the conference. Is there a good screening test for bladder cancer? Does bladder cancer lend itself to screening? Does the screening test have a high positive predictive value (does a positive test indicate the presence of disease)? And, is there a favorable natural history and treatment for the disease? At that time it was suggested that screening for bladder cancer had not been thoroughly evaluated. In the intervening years, extensive work in the development of appropriate screening tests for bladder cancer has been done, but few reports have identified screening tests for high-risk groups. The conference of 1989, sought answers to some new questions. Which bladder cancer screening tests need validation studies? Which tests are effective for early detection? Does early detection allow for better intervention? Should screening recommendations be made to high-risk groups? If so, how? Finally, should there be a controlled clinical trial to establish the therapeutic efficacy of early detection and intervention? Urgency is critical in obtaining reliable answers to these questions because many high-risk individuals have not experienced the average 20-year latency period for occupational and environmental bladder cancer. The conference critically reviewed current knowledge and discussed future challenges facing government, labor, industry and academia in screening high-risk groups for bladder cancer. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Conferences, meetings and seminars, Medical screening, Health screening

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Screening workers exposed to 4,4'-methylenebis(2-chloroaniline) for bladder cancer by cystoscopy

Article Abstract:

The aromatic amine, 4,4'-methylenebis(2-chloroaniline) (MBOCA), is highly carcinogenic for rats and induces bladder tumors in dogs. The human health effects of this aromatic amine have not been well documented, because of the lack of a sufficiently large study group. In 1981 an epidemiologic study was initiated to determine the prevalence and incidence of aromatic amine-related bladder cancer in humans. The participants included 552 workers employed in the production of MBOCA from 1968 through 1979. This cohort was one of two engaged in US production of MBOCA but, the only one not exposed to benzidine and beta-naphthylamine. Employees were initially interviewed by telephone concerning their MBOCA exposure, other potential risk factors, and health history, including history of bladder tumors. Of the original 552 workers, 452 participated in the telephone interview and 385 submitted urine specimens for testing. Sixteen initial specimens were positive for heme (blood) and 21 revealed atypical cytology. Cystoscopic examinations were offered to those who had the greatest potential exposure to MBOCA. An exposure scale was established and, based on its interpretation, cystoscopy was also made available to other employees. Various participants reported bladder tumors at intervals subsequent to the laboratory determinations of the study. The outcome of this research illustrated the difficulty in screening these high-risk cohorts. Regarding the carcinogenicity of MBOCA, conclusions were limited because of the lack of other needed corroborative data. None of the individuals who subsequently reported bladder tumors had abnormal findings in the initial study. The value of routine cystoscopy in screening asymptomatic, but high-risk groups, is questioned. (Consumer Summary produced by Reliance Medical Information, Inc.)

Demographic aspects, Aromatic amines, Cystoscopy

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A protocol for bladder cancer screening and medical surveillance among high-risk groups: the Drake Health Registry experience

Article Abstract:

The Kilsdonk and Drake Chemical Companies operated in Pennsylvania from 1940 to 1981. After they closed, the area around the plant that had been used as a disposal site was declared a hazardous site under the Superfund and was eligible for emergency cleanup. The plant manufactured the bladder carcinogen beta-naphthylamine (BNA), which was utilized as an intermediate in the manufacture of dyes and antioxidants until it was banned. The Drake Health Registry Study (DHRS) was established to screen former employees at high risk of developing bladder cancer because of possible occupational exposure to BNA. Epidemiologic studies in the region where the plants had operated indicated a 20-fold increase in the incidence of bladder cancer, compared with other local rates. Of 366 former employees who were considered eligible for the DHRS screening efforts, 261 registered. They were relatively young and most had been hired after 1970. Tests on a voided urine specimen included hematuria (dipstick and microscopic), a Papanicolaou (PAP) cytology, and a quantitative fluorescence image analysis (QFIA). Additional specific cytological staining procedures were applied as indicated by the results of the other tests. The protocols of the DHRS were modified with advances in techniques and biomedical science. The protocols have been successful in identifying very early changes in bladder tissue in a relatively young cohort of exposed workers. These individuals must be followed carefully to assure them of adequate medical surveillance and care. (Consumer Summary produced by Reliance Medical Information, Inc.)

Laws, regulations and rules, Carcinogens, Amines

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