Talc and mesothelioma: mineral fiber analysis of 65 cases with clinicopathological correlation

Our plain-English summary of Talc and mesothelioma: mineral fiber analysis of 65 cases with clinicopathological correlation, by V.L. Roggli, J.M. Carney, T.A. Sporn, et al (Ultrastructural Pathology, 2020).

The study

• Authors: V.L. Roggli, J.M. Carney, T.A. Sporn, E.N. Pavlisko
• Journal: Ultrastructural Pathology
• Published: 2020;44(2):211-218
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesothelioma is strongly associated with prior asbestos exposure. Recently there has been interest in the role of talc exposure in the pathogenesis of mesothelioma. We have analyzed lung tissue samples from a large series of malignant mesothelioma patients. Asbestos bodies were counted by light microscopy and mineral fiber concentrations for fibers 5 µm or greater in length were determined by scanning electron microscopy equipped with an energy dispersive spectrometer. The values were compared with 20 previously published controls. Among 609 patients with mesothelioma, talc fibers were detected in 375 (62%) and exceeded our control values in 65 (11%). Elevated talc levels were found in 48/524 men (9.2%) and 17/85 women (20%). Parietal pleural plaques were identified in 30/51 informative cases (59%) and asbestosis in 5/62 informative cases (8%). Commercial amphiboles (amosite and/or crocidolite) were elevated in 52/65 (80%) and noncommercial amphiboles (tremolite, actinolite or anthophyllite) in 41/65 (63%). Both were elevated in 34/65 (52%). Asbestos body counts by light microscopy were elevated in 53/64 informative cases (83%). A history of working in industries associated with asbestos exposure and increased mesothelioma risk was identified in 36/48 cases in men, and a history of exposure as household contacts of an occupationally exposed individual was identified in 12/17 cases in women. We conclude that among patients with mesothelioma, the vast majority have talc levels indistinguishable from background. Of the remaining 11% with elevated talc levels, the vast majority (80%) have elevated levels of commercial amphibole fibers.

In plain English

This study reviewed lung-tissue fiber analyses from 609 people with confirmed mesothelioma, drawn from one author's consultation files at Duke University. The results were compared with 20 control lungs. Fibers 5 µm or longer were counted by electron microscopy. Talc was found in 375 of the 609 cases (62%) and in 11 of the 20 controls (55%). Talc levels were above the control range in 65 cases (11%), made up of 48 men and 17 women. Among these 65, 52 (80%) also had raised levels of the commercial amphiboles amosite and/or crocidolite, and 41 (63%) had raised tremolite, actinolite or anthophyllite. Asbestos body counts were raised in 53 of 64 cases. Twelve of the 17 women had been household contacts of an asbestos worker. In six cases, talc was the only mineral fiber raised on electron microscopy. One of these six had raised asbestos body counts, and another had pleural plaques. For the other four, the authors thought idiopathic or spontaneous mesothelioma more likely than talc. The authors concluded that mesothelioma related to industrial talc exposure is quite rare in their experience. They noted that the study was retrospective and had no information on cosmetic talc 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: retrospective case series of lung-tissue mineral fiber analyses (light microscopy asbestos body counts and scanning electron microscopy with energy dispersive x-ray analysis), compared with control lungs
• Who was studied: 609 pathologically confirmed mesothelioma cases (524 men, 85 women) from the consultation files of one author at Duke University Medical Center, compared with 20 control lungs that were normal at autopsy with no evidence of asbestos-related disease. The 65 cases with talc above the control range (48 men, 17 women; 61 pleural, 4 peritoneal; median age 72) were studied in detail. Study dates were not given.
• Exposure: Lung-tissue content of talc fibers, commercial amphiboles (amosite, crocidolite), noncommercial amphiboles (tremolite, actinolite, anthophyllite) and asbestos bodies, counting fibers 5 µm or longer, together with recorded occupational and household exposure histories
• Main results:
  • Talc was detected in 375 of 609 mesothelioma cases (62%): 303 men (58%) and 72 women (85%). It was also detected in 11 of 20 control cases (55%).
  • Talc levels exceeded the range seen in controls in 65 cases (11%): 48 men (9.2%) and 17 women (20%).
  • In the 65 elevated-talc cases, the median talc concentration was 19,500 fibers per gram of wet lung (range 11,000 to 138,000). In the 11 controls with detectable talc, the median was 1130 fibers per gram.
  • Commercial amphibole fibers were increased in 52 of 65 elevated-talc cases (80%), including 11 of 17 women (65%).
  • Noncommercial amphibole fibers were increased in 41 of 65 elevated-talc cases (63%), including 11 of 17 women (65%). Both commercial and noncommercial amphiboles were increased in 34 of 65 (52%).
  • Asbestos body counts by light microscopy were increased in 53 of 64 elevated-talc cases (83%), including 12 of 17 women (71%).
  • Among the elevated-talc cases, parietal pleural plaques were present in 30 of 51 informative cases (59%) and asbestosis in 5 of 62 informative cases (8%).
  • Of the 17 women with elevated talc, 12 had been household contacts of an asbestos worker: a husband in 10, and a father or a son in 1 instance each.
  • Seven elevated-talc cases had raised noncommercial amphiboles but not commercial amphiboles.
  • In six cases (three women, three men), talc was the only mineral fiber raised on scanning electron microscopy. One of these six had a household asbestos exposure (son of a pipefitter) and raised asbestos body counts by light microscopy. Another was a painter and sandblaster with pleural plaques.
  • The remaining four of these six had jobs not usually associated with increased mesothelioma risk. For these, the authors thought idiopathic or spontaneous mesothelioma more likely than talc as the cause.
• The authors' conclusion: The authors concluded that talc is elevated in only 11% of the mesothelioma cases they studied, that 80% of those cases also had elevated commercial amphibole fibers, and that mesothelioma related to industrial talc exposure is quite rare in their experience. They called for future study of cases with cosmetic talc exposure.
• Limitations the authors state:
  • The study was retrospective.
  • The authors had no information on possible exposure to cosmetic talc.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma, Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Talc, Mesothelioma, Mineral Fiber, Asbestos Exposure, Asbestos Bodies, Scanning Electron Microscopy (SEM), Pleural Plaques, Amphibole Group.

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