Asbestos fibers in ovarian tissue from Norwegian pulp and paper workers

Our plain-English summary of Asbestos fibers in ovarian tissue from Norwegian pulp and paper workers, by H. Langseth, B.V. Johansen, J.M. Nesland, et al (International Journal of Gynecological Cancer, 2007).

The study

• Authors: H. Langseth, B.V. Johansen, J.M. Nesland, K. Kjaerheim
• Journal: International Journal of Gynecological Cancer
• Published: 2007;17(1):44-9
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

An elevated risk of ovarian cancer has been observed in Norwegian pulp and paper workers who were possibly occupationally exposed to asbestos. The present study was initiated to investigate if the increased risk could be associated with asbestos fibers in ovarian tissue from workers in this industry. Normal ovarian tissue specimens from three groups of women were included in the study. The case group included specimens from 46 women diagnosed with ovarian cancer in the period 1953-2000, and who had been working in one or more pulp and paper mills between 1920 and 1993. Normal ovarian tissue specimens from two control groups without occupational history from pulp and paper work were selected from the Cancer Registry database. Tissue blocks were digested and prepared for transmission electron microscopy. Number of fibers per gram wet weight was calculated. Asbestos fibers were found in normal ovarian tissue from two subjects in the case group, while no fibers were found in the control groups. The two asbestos positive cases had been working as paper sorter/packer and chlorine plant worker, respectively. Both were possibly secondary exposed to asbestos from family members working as insulators. We conclude that the findings in this study did not allow drawing any firm conclusion about an association between occupational exposure to asbestos and ovarian cancer in Norwegian pulp and paper workers. Our study confirms that asbestos fibers may reach the ovaries and demonstrates that the applied method is appropriate for identification of the fibers.

In plain English

This study looked for asbestos fibers in ovarian tissue from Norwegian women who had worked in pulp and paper mills, an industry where a raised risk of ovarian cancer had been observed. The case group was 46 women diagnosed with ovarian cancer in 1953–2000 who had worked at least 1 year in the mills between 1920 and 1993. Two comparison groups of 46 women each were drawn from the Cancer Registry of Norway: one with ovarian cancer and one with early-stage cervical cancer. Tissue was available for 31 cases and for 41 and 45 comparison women. Using transmission electron microscopy, the authors found asbestos fibers in normal ovarian tissue from two women in the case group and in none of the comparison women. One woman, a paper sorter/packer, had chrysotile and crocidolite (414,780 fibers per gram wet weight). The other, a chlorine plant worker, had chrysotile and anthophyllite (260,514 per gram). Both had lived with insulation workers. Comparing the case group with both comparison groups combined gave a P value of 0.07. The authors concluded that the findings did not allow any firm conclusion about an association between asbestos exposure and ovarian cancer in these workers. They added that the study confirmed that fibers may reach the ovaries.

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: Histopathologic (tissue) study comparing asbestos fiber content, measured by transmission electron microscopy, in archived tissue from a case group of pulp and paper workers with ovarian cancer and two control groups
• Who was studied: Three groups of 46 women each in Norway. The case group was women diagnosed with ovarian cancer in 1953–2000 who had worked at least 1 year in pulp and paper mills between 1920 and 1993. Control group I was ovarian cancer patients and control group II was stage I cervical cancer patients whose healthy ovaries had been removed, both selected from the Cancer Registry and without pulp and paper work history. After exclusions, tissue was available for 31 cases and for 41 and 45 controls.
• Exposure: Possible occupational asbestos exposure in the Norwegian pulp and paper industry, where asbestos was used as insulation material, and household (secondary) exposure from family members' work. The study measured asbestos fibers per gram wet weight of ovarian tissue.
• Main results:
  • Asbestos fibers were found in normal ovarian tissue from two women in the case group. No fibers were found in either control group.
  • Case 1, a paper sorter/packer from 1954 to 1961 whose husband was an insulator, had 414,780 asbestos fibers per gram wet weight (3 chrysotile and 1 crocidolite fiber counted).
  • Case 2, a chlorine plant worker for 2.5 years (1973–1976) who had lived with a family member working in insulation, had 260,514 asbestos fibers per gram wet weight (2 anthophyllite and 1 chrysotile fiber counted).
  • The two fiber-positive women were the only ones in the case group to report household asbestos exposure from family members who were insulators. Ten fiber-negative cases reported household exposure from family members in occupations considered less exposed.
  • A test comparing the proportion of asbestos-positive women in the case group with the two comparison groups merged gave a P value of 0.07.
  • In a pilot test of the method on tissue from four pleural mesothelioma patients, asbestos fibers were found in all samples.
• The authors' conclusion: The authors concluded that the findings did not allow any firm conclusion about an association between asbestos exposure and ovarian cancer risk in Norwegian pulp and paper workers. They stated that the study confirms asbestos fibers may reach the ovaries and that the method is appropriate for identifying the fibers.
• Limitations the authors state:
  • Access to normal tissue differed between groups: specimens were available for 67% of the case group, and for 89% and 98% of the two control groups.
  • For eight women in the case group, the only normal tissue available was from fallopian tubes or omentum. The authors noted they might have found fibers in more cases with tissue from all subjects.
  • Only a small number of women in the case group were possibly exposed to asbestos.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Anthophyllite, Chrysotile, Crocidolite, Ovarian cancer.

Medical terms in this study, explained in our Lexicon: Ovarian Cancer, Occupational History, Cancer Registry, Paraffin Block, Transmission Electron Microscopy (TEM), Fibers Per Gram, Insulator, Occupational Exposure.

Related studies

• Correlation of asbestos fiber burdens in fallopian tubes and ovarian tissue — D.S. Heller, R.E. Gordon, et al. (1999)
• Cohort mortality study of pulp and paper mill workers in British Columbia, Canada — P.R. Band, N.D. Le, et al. (1997)
• Exposure to asbestos and lung and pleural cancer mortality among pulp and paper industry workers — R. Carel, P. Boffetta, et al. (2002)
• Asbestos exposure and ovarian fiber burden — D.S. Heller, R.E. Gordon, et al. (1996)
• Expression of calretinin in human ovary, testis, and ovarian sex cord-stromal tumors — Q.J. Cao, J.G. Jones, et al. (2001)
• A new policy regarding ovarian resection in young women treated for peritoneal carcinomatosis — D. Elias, E. Duchalais, et al. (2013)

Browse more research in International Journal of Gynecological Cancer, or return to medical research.