Occupational exposure to asbestos and urinary bladder cancer

Our plain-English summary of Occupational exposure to asbestos and urinary bladder cancer, by R. Molinini, L. Paoletti, M. Albrizio, et al (Environmental Research, 1992).

The study

• Authors: R. Molinini, L. Paoletti, M. Albrizio, A. Pennella, F. Nardulli, G. Caruso
• Journal: Environmental Research
• Published: 1992;58(2):176-83
• Type of article: Case report
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004886).

Abstract

By the use of transmission electron microscopy (TEM) and energy dispersion spectrometry the amount (mean value mean = 191 +/- 94 fibers/mg of tissue) and the type (chrysotile and tremolite) of asbestos fibers have been determined in tissue samples of four bladder cancer patients affected by pulmonary asbestosis, working in the same plant producing asbestos-cement pipes and boards. Similar measurements were carried out on samples of bladder cancers of eight control patients not professionally exposed to asbestos. Only five of them also revealed chrysotile fibers (mean = 151 +/- 196 fibers/mg of tissue). The paucity of the study and control cases and the small quantitative difference between them regarding the presence of infraneoplastic asbestos fibers does not consent us to hypothesize a causal relationship between tumor and occupational exposure.

In plain English

This report described four former workers from one asbestos-cement plant in Bari, Italy, all diagnosed with pulmonary asbestosis, who later developed bladder cancer. The plant used chrysotile, crocidolite and amosite. Using electron microscopy, the authors looked for asbestos fibers in stored bladder tumor samples from these four workers. They did the same for eight bladder cancer patients recorded as not occupationally exposed to asbestos. All four workers' tumors contained fibers, averaging 191 fibers per milligram of tissue. The fibers were chrysotile, with tremolite also found in one case. Five of the eight control tumors contained chrysotile, and the control group averaged 151 fibers per milligram. The workers' average was higher, but the difference was not statistically significant. The authors noted that asbestos fibers are common in city environments and that exposure histories were partly taken from relatives of patients who had died. They also noted that contamination of the archived samples could not be fully excluded. They concluded that their small study did not establish a causal link between bladder cancer and occupational asbestos exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case series (four case reports) with a tissue fiber-burden comparison against eight control bladder tumors, using transmission electron microscopy and energy dispersion spectrometry
• Who was studied: Four former workers of the same asbestos-cement plant in Bari, Italy, all with pulmonary asbestosis and bladder urothelial carcinoma, referred for occupational disease recognition and compensation. The comparison group was eight bladder tumor patients from the same three Bari pathology laboratories who did not have pulmonary asbestosis and had not been occupationally exposed to asbestos according to their records.
• Exposure: Work of 13 to 35 years in a plant of about 160 employees producing asbestos-cement pipes and corrugated sheets. The mixtures contained 15-20% asbestos, made up of chrysotile (60-80%), crocidolite (20%) and amosite (10-20%).
• Main results:
  • In the four exposed workers, asbestos fibers were found in all bladder tumor samples, with a mean of 191 fibers per mg of tissue (standard deviation 94). The fibers were chrysotile, plus tremolite in one case.
  • Among the eight control patients, five had chrysotile fibers in their tumor samples. The control group mean was 151 fibers per mg of tissue (standard deviation 196).
  • The mean fiber concentration was lower in the control cases than in the exposed workers, but the difference was not statistically significant.
  • The three samples with no fibers detected were all from control cases.
  • In the exposed workers, the fibers had a mean length of 8.0 micrometers and a mean diameter of 0.16 micrometers. In the positive control cases, the mean length was 11.0 micrometers and the mean diameter 0.13 micrometers.
• The authors' conclusion: The authors concluded that the study did not allow definitive results. In their view, the small difference in fibers within the tumors between exposed workers and controls does not establish a definite causal relationship between bladder cancer and occupational asbestos exposure. They suggested that asbestos fibers can reach the bladder and can be observed inside bladder tumor tissue.
• Limitations the authors state:
  • Very small numbers of study and control cases.
  • Asbestos fibers are common environmental contaminants, especially in large cities like Bari.
  • Exposure histories were gathered retrospectively, from relatives when the patient had died, so environmental and non-occupational asbestos exposure cannot be ruled out.
  • The samples were paraffin blocks processed years earlier in three hospitals, so contamination during laboratory processing could not be verified or totally excluded.
  • Fibers in the bladder lining surrounding the tumor were not examined.
  • Other bladder carcinogens such as cigarette smoking must be considered.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Chrysotile.

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Transmission Electron Microscopy (TEM), Chrysotile, Tremolite, Asbestosis, Asbestos-Cement Pipe.

Related studies

• Occupational cancer of the urinary bladder in dyestuffs operatives and of the lung in asbestos textile workers and iron-ore miners — G.M. Bonser, J.S. Faulds, et al. (1955)
• Occupational asbestos exposure and urinary bladder cancer: a systematic review and meta-analysis — N. Franco, A. Godono, et al. (2023)
• Use of job-exposure matrix in an occupational analysis of lung and bladder cancers on the basis of death certificates — D. Coggon, B. Pannett, et al. (1984)
• Environmental and occupational exposures and prognosis in patients with non-muscle-invasive bladder cancer in the Be-Well Study — Z. Wang, M.L. Kwan, et al. (2024)
• Arsenic, tobacco smoke, and occupation: associations of multiple agents with lung and bladder cancer — C. Ferreccio, Y. Yuan, et al. (2013)
• Lung and bladder cancer in a Norwegian municipality with iron and steel producing industry: population based case-control studies — T.K. Grimsrud, H. Langseth, et al. (1998)

Browse more research in Environmental Research, or return to medical research.