Malignant mesothelioma of the pleura: relation between histological type and clinical behaviour

Our plain-English summary of Malignant mesothelioma of the pleura: relation between histological type and clinical behaviour, by M.R. Law, M.E. Hodson, B.E. Heard (Thorax, 1982).

The study

• Authors: M.R. Law, M.E. Hodson, B.E. Heard
• Journal: Thorax
• Published: 1982;37(11):810-5
• Cited by: 83 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000684).

Abstract

The differing clinical behaviour of malignant mesothelioma of different cell types was studied in 115 cases of pleural mesothelioma, classified histologically into epithelial (60), sarcomatous (25), and mixed (30). Epithelial mesotheliomas were associated with clinical features characteristic of carcinomas rather than sarcomas, including spread of tumour by direct extension, large pleural effusions, contralateral pleural effusions, ascites, metastases in regional lymph nodes, and occasional response to radiotherapy. Sarcomatous mesotheliomas were associated with clinical features more characteristic of sarcomas, with more frequent distant metastases, little or no effusion, and shorter survival. Mixed tumours had features of both, large pleural effusions occurring as frequently as with epithelial tumours, but survival being almost as poor as in sarcomatous cases. Despite these differences there is evidence from published reports that epithelial, sarcomatous, and mixed mesotheliomas have a common origin from mesothelial cells or their precursor cells.

In plain English

This study reviewed 115 cases of malignant mesothelioma of the pleura. The patients were seen at the Brompton and London Chest Hospitals in London. The authors compared how the disease behaved by cell type. One pathologist classified 60 tumours as epithelial, 30 as mixed and 25 as sarcomatous. Average age at presentation (58 or 59 years) and documented asbestos exposure (77% to 88%) did not differ significantly between types. Large pleural effusions (fluid around the lung) occurred in 76% of epithelial and 70% of mixed cases but in 16% of sarcomatous cases. Of 41 patients given radiotherapy, eight had a partial response, and none of them had sarcomatous tumours. Survival was worst with sarcomatous tumours. After 18 months, survival with mixed tumours fell considerably, and epithelial tumours had significantly better survival than both other types up to five years. Among 60 autopsies, distant spread was found in 78% of sarcomatous cases. The authors concluded that epithelial tumours behaved more like carcinomas and sarcomatous tumours more like sarcomas. They noted that diagnosis varies somewhat between pathologists.

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: Clinicopathological case series: review of tumour tissue, clinical records and autopsy findings, comparing histological types
• Who was studied: 115 patients with malignant mesothelioma of the pleura, patients of the Brompton and London Chest Hospitals, London; study years not stated
• Exposure: Not the focus of the study. Asbestos exposure was documented in 48 of 60 epithelial, 23 of 30 mixed and 22 of 25 sarcomatous cases. Fiber types and jobs were not described.
• Main results:
  • Of the 115 tumours, 60 (52%) were epithelial, 30 (26%) mixed and 25 (22%) sarcomatous
  • Mean age at presentation was 58 years for epithelial and mixed tumours and 59 for sarcomatous tumours. Age, asbestos exposure and digital clubbing did not differ significantly between types.
  • Large pleural effusions occurred in 46 (76%) of 60 epithelial, 21 (70%) of 30 mixed and 4 (16%) of 25 sarcomatous cases. 84% of sarcomatous cases had small or no effusions (p less than 0.001).
  • Clinically detected lymph node deposits were found in 13 (22%) of 60 epithelial, 2 (7%) of 30 mixed and 2 (8%) of 25 sarcomatous cases. The difference was not significant.
  • Of 41 patients given radiotherapy, 8 had a partial response: 7 epithelial and 1 mixed. No sarcomatous case responded; the epithelial-sarcomatous difference was significant (p less than 0.05).
  • For the first 18 months after symptoms began, survival with epithelial and mixed tumours was similar and significantly better than with sarcomatous tumours (p less than 0.01).
  • After 18 months, survival with mixed tumours fell considerably. Epithelial tumours had significantly better survival than mixed or sarcomatous tumours up to five years (p less than 0.05).
  • At autopsy (60 cases), direct extension to the contralateral pleura was found in 19 (70%) of 27 epithelial, 4 (27%) of 15 mixed and 7 (39%) of 18 sarcomatous cases (p less than 0.001). Direct extension was more frequent with epithelial tumours overall.
  • Distant metastases at autopsy were found in 14 (78%) of 18 sarcomatous, 10 (37%) of 27 epithelial and 5 (33%) of 15 mixed cases (p less than 0.025). Bone metastases diagnosed during life (3 patients) were all in sarcomatous cases.
  • Contralateral effusions occurred in 9 of 19 epithelial cases with contralateral pleural extension and in none of the mixed or sarcomatous cases. Ascites occurred in 7 of 13 epithelial and 2 of 8 mixed cases with peritoneal extension, and in none of 6 sarcomatous cases.
• The authors' conclusion: The authors concluded that epithelial mesotheliomas behaved more like carcinomas and sarcomatous mesotheliomas more like sarcomas. They also concluded that mixed tumours showed features of both. Citing published reports, they considered that all three types share a common origin from mesothelial cells.
• Limitations the authors state:
  • Histological diagnosis of mesothelioma is subject to some variation between observers
  • Epithelial mesothelioma cannot always be distinguished with certainty from pleural deposits of adenocarcinoma, so uncertain tumours were excluded

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Pleura, Pleural Mesothelioma, Mesothelioma, Carcinoma, Sarcoma, Pleural Effusion, Ascites.

Related studies

• A study of the histological cell types of lung cancer in workers suffering from asbestosis in the United Kingdom — F. Whitwell, M.L. Newhouse, et al. (1974)
• Occupational exposures and risk of stomach cancer by histological type — M. Santibañez, J. Alguacil, et al. (2012)
• Occupational exposures and risk of oesophageal cancer by histological type: a case-control study in eastern Spain — M. Santibañez, J. Vioque, et al. (2008)
• Metastases in diffuse pleural mesothelioma: influence of histological type — M. Huncharek, J. Muscat (1987)
• Incidence of lung cancer by histological type among asbestos cement workers in Denmark — E. Raffn, E. Lynge, et al. (1993)
• Histological types of malignant mesothelioma and asbestos exposure — W.E. Wright, R.P. Sherwin (1984)

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