Clinical value of fluorodeoxyglucose-positron emission tomography/computed tomography in differentiation of malignant mesothelioma from asbestos-related benign pleural disease: an observational pilot study

Our plain-English summary of Clinical value of fluorodeoxyglucose-positron emission tomography/computed tomography in differentiation of malignant mesothelioma from asbestos-related benign pleural disease: an observational pilot study, by H. Yildirim, M. Metintas, E. Entok, et al (Journal of Thoracic Oncology, 2009).

The study

• Authors: H. Yildirim, M. Metintas, E. Entok, G. Ak, I. Ak, E. Dundar, S. Erginel
• Journal: Journal of Thoracic Oncology
• Published: 2009;4(12):1480-4
• Cited by: 70 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Several studies have already addressed the potential role of an increased fluorine 18 fluorodeoxyglucose (18F FDG) uptake in identification of pleural malignancy. In this pilot study, we investigate the role of 18F-FDG positron emission tomography/computed tomography (PET/CT) for differentiating asbestos-related benign pleural disease from malignant mesothelioma.

Materials And Methods: The study population comprised 31 consecutive patients (17 malignant mesotheliomas, nine benign asbestos pleurisies, and five diffuse pleural fibrosis) with a mean age of 61 years between January 2006 and December 2008. Thoracoscopy or image-guided pleural needle biopsy were systematically performed to reveal pathologic diagnosis and/or clinical follow-up for at least 3 years for presence or absence of malignant pleural effusion. ROCs analyses for standardized uptake value (SUV) adjusted to body weight were calculated between benign and malignant pleural diseases.

Results: 18F-FDG PET/CT imaging correctly detected the presence of malignancies in 15 of 17 patients with malignant mesothelioma for sensitivity, specificity, and overall accuracy of 88.2%, 92.9%, and 90.3%, respectively. 18F-FDG PET/CT imaging correctly identified 13 of 14 cases of benign pleural disease. The mean SUV values were 6.5 +/- 3.4 for malignant mesothelioma cases and 0.8 +/- 0.6 for benign pleural diseases (p < 0.001). When we compared the two groups of pleural disease, a cut-off value of 2.2 for SUV gave the best accuracy with 94.1%, 100%, 100%, and 93.3% for sensitivity, specificity, positive predictive value, and negative predictive value, respectively.

Conclusion: Preliminary results of this trial provide evidence that 18F-FDG PET/CT imaging is a highly accurate and reliable noninvasive test to decide for further investigation of differentiating malignant mesothelioma from benign pleural disease.

In plain English

This observational pilot study in Turkey tested whether 18F-FDG PET/CT scanning could tell malignant pleural mesothelioma apart from benign asbestos-related pleural disease. It included 31 patients seen between January 2006 and December 2008: 17 with mesothelioma, 9 with benign asbestos-related pleural effusion and 5 with diffuse pleural thickening. Reading the scans by eye, the nuclear medicine department correctly identified 15 of the 17 mesotheliomas and 13 of the 14 benign cases. This gave a sensitivity of 88.2%, a specificity of 92.9% and an overall accuracy of 90.3%. The one false positive was in a patient with diffuse pleural thickening. The average maximum uptake value (SUVmax) was 6.5 in the mesothelioma patients and 0.8 in the benign patients. Using a cut-off of 2.2, sensitivity was 94.1%, specificity 100%, positive predictive value 100% and negative predictive value 93.3%. The authors concluded that PET/CT can be useful in deciding on further investigation for patients with asbestos-related pleural disease. They noted that the sample was small, that the test is relatively expensive, and that predictive values depend on how common the disease is among those tested.

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: observational pilot study of a diagnostic test (18F-FDG PET/CT) in consecutively admitted patients
• Who was studied: 31 patients with pleural effusions or pleural thickening at the Department of Chest Disease, Eskisehir Osmangazi University, Turkey, January 2006 to December 2008. 40 were enrolled and 9 were excluded. The 31 were 20 men and 11 women, mean age 61 years (range 40 to 82): 17 with malignant pleural mesothelioma (11 epithelioid, 3 biphasic, 2 sarcomatoid, 1 undetermined subtype), 5 with diffuse pleural thickening and 9 with benign asbestos-related pleural effusion. The benign group was identified through a chart review and invited to have the scan.
• Exposure: Asbestos exposure; fiber types and sources are not specified. The mean exposure duration was 30.9 years in the malignant group and 12.3 years in the benign group, a difference the authors reported as significant. The test studied was 18F-FDG PET/CT.
• Main results:
  • Visual reading of the scans correctly detected 15 of 17 mesothelioma cases.
  • The 2 missed mesotheliomas showed no FDG uptake; one was epithelial subtype and one sarcomatoid.
  • 13 of 14 benign cases were correctly identified. The one false positive was a patient with diffuse pleural thickening.
  • None of the patients with benign asbestos-related pleural effusion showed FDG uptake in the pleura.
  • For detecting pleural mesothelioma by visual reading, sensitivity was 88.2%, specificity 92.9% and overall accuracy 90.3%.
  • The mean SUVmax in the mesothelioma patients was 6.5. Uptake was significantly higher than in the benign patients.
  • The mean SUVmax in the benign pleural disease patients was 0.8.
  • The area under the ROC curve for SUVmax was 0.983.
  • With an SUVmax cut-off of 2.2, sensitivity was 94.1%, specificity 100%, positive predictive value 100% and negative predictive value 93.3%. One mesothelioma patient fell below the cut-off, with an SUVmax of 1.49.
• The authors' conclusion: The authors concluded that 18F-FDG PET/CT can be useful in deciding on further investigations for patients with asbestos-related pleural diseases. They also suggested it may limit unnecessary invasive procedures.
• Limitations the authors state:
  • The sample size was relatively small.
  • PET/CT is a relatively expensive imaging technique.
  • The predictive values of a test depend on how common the disease is among those tested. The authors believed close follow-up is necessary in most patients with low uptake values.

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: Malignant Mesothelioma, Fibrosis, Thoracoscopy, Needle Biopsy, Pleural Effusion.

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