Pleural fluid CEA levels in the diagnosis of malignant mesothelioma

Our plain-English summary of Pleural fluid CEA levels in the diagnosis of malignant mesothelioma, by D. Whitaker, K.B. Shilkin, M. Stuckey, et al (Pathology, 1986).

The study

• Authors: D. Whitaker, K.B. Shilkin, M. Stuckey, W.N. Nieuwhof
• Journal: Pathology
• Published: 1986;18(3):328-9
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A study was undertaken to investigate whether the levels of carcino-embryonic antigen (CEA) in serous effusions helped distinguish between primary mesothelioma and metastatic adenocarcinoma in a body cavity. The investigation was designed to assess the role of the assay only when cytological analysis of the fluid had already shown the presence of malignant cells. No case of mesothelioma studied had levels of CEA above 2.9 ng/ml, whereas 67% of the adenocarcinomas tested were above 15 ng/ml. The test is helpful, therefore, in differentiating between these two types of malignant effusions.

In plain English

This study, from Perth, Australia, asked whether measuring carcino-embryonic antigen (CEA) in fluid collected around the lungs (pleural effusion) could help tell malignant mesothelioma apart from adenocarcinoma that had spread there from elsewhere. The authors selected 20 fluid samples each from patients with mesothelioma, adenocarcinoma and benign (non-cancerous) effusions. The samples had been sent for routine testing at Sir Charles Gairdner Hospital from 1980 to 1983, and the authors measured CEA in them with a laboratory assay. In every mesothelioma sample, CEA was no higher than 2.9 ng/ml. All benign effusions were below 10 ng/ml. Adenocarcinoma samples ranged from 0 to more than 60 ng/ml. Using 15 ng/ml as a cut-off, 67% of adenocarcinomas could be classified as such, and the difference between mesothelioma and adenocarcinoma was statistically significant (p less than 0.01). The authors concluded that once cytology has shown cancer cells in the fluid, a CEA level above 15 ng/ml indicates adenocarcinoma rather than mesothelioma, and that the test is best used as a second-level step. They noted that CEA alone cannot show whether a fluid is malignant. The article did not discuss asbestos.

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: Laboratory diagnostic study comparing CEA levels in stored pleural fluid samples from selected cases of mesothelioma, adenocarcinoma and benign effusion
• Who was studied: Pleural effusion samples sent for routine cytodiagnosis from patients at Sir Charles Gairdner Hospital, a 700-bed general teaching hospital (Perth), 1980-1983: 20 mesothelioma, 20 adenocarcinoma, 20 benign effusion
• Exposure: Not an exposure study. No asbestos or fiber exposure is reported. The factor measured was the level of CEA in pleural fluid, using the Abbott CEA-EIA monoclonal assay.
• Main results:
  • Mesothelioma effusions: all had low CEA levels, none greater than 2.9 ng/ml
  • Benign effusions: all CEA levels below 10 ng/ml, the highest being 6 ng/ml
  • Adenocarcinoma effusions: CEA ranged from 0 to greater than 60 ng/ml
  • With a 15 ng/ml cut-off, 67% of adenocarcinomas could be classified as such on CEA level alone
  • At that cut-off, the difference between mesothelioma and adenocarcinoma was statistically significant (p less than 0.01)
• The authors' conclusion: The authors concluded that, where cytology has already shown the fluid to be malignant and the question is adenocarcinoma versus mesothelioma, a fluid CEA level above 15 ng/ml indicates adenocarcinoma. They said the test is best applied as a second-level discriminator within a diagnostic protocol.
• Limitations the authors state:
  • The authors stated that CEA testing alone cannot determine whether a fluid is malignant, because benign effusions have CEA levels overlapping those of some malignancies
  • The authors stated, citing other work, that the test has low predictive value when cut-off points are chosen for high specificity

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Adenocarcinoma.

Related studies

• Utility of hyaluronic acid in pleural fluid for differential diagnosis of pleural effusions: likelihood ratios for malignant mesothelioma — S. Atagi, M. Ogawara, et al. (1997)
• Evaluation of pleural CYFRA 21-1 and carcinoembryonic antigen in the diagnosis of malignant pleural effusions — G. Salama, M. Miédougé, et al. (1998)
• Vascular endothelial growth factor in pleural fluid for differential diagnosis of benign and malignant origin and its clinical applications — A. Fiorelli, G. Vicidomini, et al. (2011)
• Significance of secretory leukocyte peptidase inhibitor in pleural fluid for the diagnosis of benign asbestos pleural effusion — T. Kishimoto, Y. Kojima, et al. (2021)
• Evaluation of predictive value of pleural CEA in patients with pleural effusions and histological findings: A prospective study and literature review — R. Tozzoli, S.M. Basso, et al. (2016)
• The role of cytologic evaluation of pleural fluid in the diagnosis of malignant mesothelioma — A.A. Renshaw, B.R. Dean, et al. (1997)

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